how to experiment surface tension

7 Surface Tension Experiments To Try With Kids

• November 2, 2022
• Science Experiments

Here is a list of easy and fun surface tension experiments for kids. These surface tension experiments with water can help kids learn about static water and the forces within it.

Do you love the 4th of July milk fireworks?

What if you can create them using milk?

Have you noticed crazy little balls in your coffee mug while stirring it?

Well, it’s possible to recreate them! There are lots of other factors to know. So, let’s have a look at the seven science experiments that will help to understand physics in a better way while having fun at home.

1. Milk Fireworks        

This is an easy science activity that needs only a few raw materials and can prove to be a great boredom buster. 

Raw materials 

• A dish 
• Food coloring agents 
• Liquid dish soap

Required Steps 

• Take the dish and pour some milk into it.
• Now drop a few drops of coloring agents in the middle.
• Now take an earbud soaked in liquid dish soap and dip it into the middle with food coloring agents. 
• The colors get scattered in all directions like fireworks! 

Observation

Experiment Observing that adding little soap to the milk weakens its surface tension by pushing the milk molecules with its hydrophobic ends. Also, the food coloring agents are pushed along with them, and end up having a spectacular sight of  fireworks on liquids !

Note: You can conduct this experiment with milk at different temperatures such as warm and very cold to see whether this will make any difference to the behavior of the milk molecules.

2. Water BBS

This experiment demonstrates how crazy little balls notice in the coffee mug while stirring it.

• One cup of coffee
• One coffee stirrer
• Few drops of liquid soap

Required steps

• Take the coffee mug and stir it with the stirrer
• Maybe nothing will happen, and then mix a few drops of liquid soap

In this experiment, notice some little balls in the coffee mug, which are nothing but anti-bubbles. These bubbles are formed when a liquid is dropped turbulently into the same or another liquid.

These are thin films of gas enclosing a sphere of liquid that can appear and then get fully submerged in the liquid.

Unlike ordinary air bubbles, these anti-bubbles do not rise quickly on the top. Patient to see them as they are quite mesmerising.

3. Soap Boat

This science activity video on a  soap boat experiment  is all about the surface tension of water and the impact of soap on water.

• 1 dish containing water
• 1 little boat with a notch out of a card
• A few cotton buds
• Liquid soap
• Take the dish and place the little paper boat on the surface of the water
• Now, soak the cotton bud in liquid soap and touch its tip into the water to power your paper boat

In this experiment, the boat will start moving swiftly! Now, this happens when you touch the soap on the surface of the water. Soap weakens its surface tension and creates enough force to push the lightweight paper boat. Interesting to notice it!

4. Floating Card

• 1 open jar with a mesh screen on its mouth  
• 1 card 
• 1 jug of water
• Take the open jar with the mesh screen and pour water into it from the jug
• Now, take the card and place it gently in the mouth of the jar
• Invert the jar, and you will see that it will uphold the card!
• Next, gently remove your hand from the card
• Slid out the card from beneath the jar
• The jar will hold up the water mysteriously!

 Observation

Observations help to notice the  mysterious water suspension.  So, the science behind this  floating water trick  is nothing but the surface tension across the screen, which holds up the water.

There is also a role of cohesion to play in this science activity. It is the cohesion that causes surface tension. Here, water molecules remain joined together between each tiny opening of the screen mesh and form a thin invisible membrane that is strong enough to hold the water when the jar is inverted.

You can even stick some needles inside the jar! Interestingly, the surface tension will successfully prevent the water from falling in that case too! 

You can use this experiment as a magic trick before your friends and can, later on, explain to them the science behind the water suspension.

5. Suddenly sinking paper clips

This science activity video on  paper clip floating  and sinking is again about the surface tension of water.

• 1 glass containing water
• 1 paper clip
• 1 piece of tissue paper
• A small quantity of liquid soap
• Take the paper clip and place it on top of the water surface of the glass
• Try to balance it on the water surface
• If it sinks, take it out from the glass
• Now, place the piece of small tissue paper on the water surface and then put the paper clip on it
• Next, gently remove the tissue paper from beneath the paper clip as it will start floating on the water surface
• Now take the Q-tip and soak it in liquid soap and touch its tip into the water
• The paper clip will again sink at the bottom! 

Now, wondering why is the  paper clip floating on water soap?  Well, the reason is again the humble surface tension! 

In the second step, then try to make the paper clip float on the water surface, it sinks because the metal with which the clip is made is denser than the water. 

However, when placing it on a piece of floating tissue paper, it does not sink because now the surface tension of the water is supporting it.

Again, when you touch the water with soap, this surface tension gets reduced. So, the clip sinks like a brick into the glass. 

Also, let’s experiment with this interesting activity with different lightweight objects to see whether the same thing is happening again. 

6. Penny Dropper

Have you ever wondered  how many drops of water can fit on a penny ?

Well, this super fun science activity will give all the answers. 

• 1 plastic dropper 
• Take the penny and place it on a flat surface
• Now take the dropper, fill it with water, and put a drop of water at the center of your penny
• Keep on adding water drops to the penny and count
• A dome shape made up of water drops will form on the penny 

The experiment makes us observe that a penny can hold several water drops before it eventually starts spilling over the coin. Here, it is the surface tension of water that prevents the water molecules from falling apart. So, the water molecules remain together and form a dome shape. Even Experimenting with other liquids such as saltwater, milk, and soapy water to figure out whether they yield the same result or not.

7. Leidenfrost Effect        

Have you ever heard about the  Leindenfrost effect ?

Well, it is a phenomenon where liquids, instead of getting evaporated, glided on the surface of a pan. This happens when the pan is heated beyond the boiling point of that liquid. 

This effect was named after the German doctor Johann Gottlob Leidenfrost (1715-1794), who described this effect. 

However, to do this exciting science experiment, you will need adult supervision as this involves heat hazards! 

• 1 empty pan
• One dropper
• Take the empty pan and put it on a stove.
• Next, add some water droplets into the pan one by one with the help of the dropper, and the water droplets will quickly evaporate. 
• Keep on adding the water droplets but now increase your speed. 
• Water droplets will now not evaporate. They will instead make small spheres gliding on the hot surface of the pan.

The observation makes us wonder how  does water dance on a hot pan . See, when heating the pan more than the boiling point of water, which is 100-degree Celsius, water drops vaporize quickly that it forms a layer of steam that insulates the rest of the water droplets are added from the hot surface of the pan. As a result, you end up watching the dancing water droplets. 

All the above activities can be done at home to develop a better understanding of some key concepts of physics. 

Dianna Cowern, also called physics girl presented a video of seven experiments or science tricks that offer surface tension, anti-bubble, cohesion, and lienenforst effect.

Courtesy: Physics Girl

https://www.youtube.com/watch?v=WsksFbFZeeU&feature=emb_logo

https://www.antibubble.org/

https://www.stevespanglerscience.com/lab/experiments/water-screen/

https://msdlt.instructure.com/courses/108/files/2571/download?wrap=1

https://www.rookieparenting.com/how-many-drops-of-water-can-you-put-on-a-penny/

https://www.sociologygroup.com/water-drops-dance-hot-plate/

Leave a Reply Cancel Reply

Your email address will not be published. Required fields are marked *

Name  *

Email  *

Add Comment  *

Save my name, email, and website in this browser for the next time I comment.

Post Comment

• Skip to primary navigation
• Skip to main content
• Skip to primary sidebar

• FREE Experiments
• Kitchen Science
• Climate Change
• Egg Experiments
• Fairy Tale Science
• Edible Science
• Human Health
• Inspirational Women
• Forces and Motion
• Science Fair Projects
• STEM Challenges
• Science Sparks Books
• Contact Science Sparks
• Science Resources for Home and School

Surface Tension of Water Demonstration

April 17, 2019 By Emma Vanstone 3 Comments

These super simple investigations are great for demonstrating the surface tension of water .

What is surface tension?

Surface tension  is a force which causes a layer of liquid to behave like an elastic sheet or skin.

Molecules of water are more attracted to each other than other molecules, as water is a polar molecule. The positive hydrogen end of one molecule is attracted to the negative oxygen end of another water molecule. The surface water molecules only have air above them, so they are pulled down, creating surface tension.

The high surface tension of water allows insects to walk over it. Pond skaters have long, hairy legs, allowing them to spread their weight over a wide area. They press very gently on the water’s surface so as not to break through it.

In a container of water, molecules below the surface are pulled together ( or attracted to each other ) equally in all directions, but those on top are pulled together more tightly, as they don’t have water molecules above them; this draws them together to form a ‘skin’. It is this skin ( surface tension ) that stops items on the surface from sinking.

Surface Tension Holes Experiment

You’ll need.

A big bowl of water

Some ground pepper (black so you can see it) or any other ground product with colour

Washing up liquid ( dish soap )

Once the water settles, sprinkle the ground pepper over the top.

Drip some washing-up liqu id in the middle of the bowl and watch what happens.

A hole appears in the centre as the pepper moves outwards. This is your surface tension hole !

If you want to repeat the demonstration, you’ll need to wash out the bowl thoroughly to remove any traces of the dish soap ( washing up liquid ), or the effect won’t be as dramatic.

Why does this happen?

The surface tension hole is caused by the washing up liquid reducing the surface tension of the water. This allows the particles of water at the surface to spread out, starting from where the washing-up liquid was added.

More Surface Tension Experiments for Kids

Frugal Fun for Boys has an excellent surface tension investigation using a coin and different liquids !

You can use washing-up liquid to disrupt the surface tension of water to race lolly sticks .

In a magic milk experiment , the washing up liquid disrupts the surface tension of the milk, which makes food colouring spread out just like the pepper and water.

Another surface tension experiment is where you make a shape on the surface of the water with cocktail sticks and drop some washing-up liquid in the centre to force the sticks apart.

Watch how water behaves on the space station with this NASA video.

Try filling a bowl half full with water and carefully placing a paperclip on the top, so it floats. Mix a little washing-up liquid in a cup with water and gently pour it into the bowl; the paper clip will sink as the water can no longer support the weight of the paper clip after the washing-up liquid disrupts the surface tension of the water.

Science concepts

Surface tension

Last Updated on July 8, 2023 by Emma Vanstone

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

October 16, 2011 at 3:00 pm

Great activity, I am going to try it with my daughter! I love how you call it “washing up liquid” – I call it that too. 🙂

October 16, 2011 at 9:26 pm

Thanks, glad you like it!

October 21, 2011 at 6:01 pm

So many great ideas come form this blog! Thank you for linking up to the The Sunday Showcase

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Surface Tension - Definition and Experiments

Understand Surface Tension in Physics

• Physics Laws, Concepts, and Principles
• Quantum Physics
• Important Physicists
• Thermodynamics
• Cosmology & Astrophysics
• Weather & Climate

Surface Tension Experiments

Science can be absolutely hands-on and engaging for kids. Learn about the surface tension of water with our simple definition below. Plus, check out these fun surface tension experiments to try at home or in the classroom. As always, you’ll find fantastic and easy to do science experiments at the tip of your fingers.

What Is Surface Tension Of Water?

Surface tension exists on the surface of water because water molecules like to stick to each other. This force is so strong that it can help things sit on top of the water instead of sinking into it. Like our pepper and soap experiment below.

It is the high surface tension of water that allows a paper clip, with much higher density, to float on water. It also causes drops of rain to stick to your windows, and is why bubbles are round. Surface tension of water also helps propels water-striding insects on the surface of ponds.

Also learn about capillary action !

Scientist, Agnes Pockels discovered the science of surface tension of fluids simply doing the dishes in her own kitchen.

Despite her lack of formal training, Pockels was able to measure the surface tension of water by designing an apparatus known as the Pockels trough. This was a key instrument in the new discipline of surface science. In 1891, Pockels published her first paper, “Surface Tension,” on her measurements in the journal Nature.

Easy Surface Tension Experiments

Here are some fun ways to demonstrate the surface tension of water. Plus, all you need is a handful of common household supplies. Let’s play with science today!

Bubble Snakes

Find out how you can blow up a gigantic bubble snake all with the help of surface tension.

Drops Of Water On A Penny

A fun science activity with pennies and water. How many drops of water do you think you can get on a penny? The results might surprise you and all because of surface tension!

Floating Paperclip Experiment

How do you make a paperclip float on water? Learn about surface tension of water, with a few simple supplies.

Magic Pepper and Soap Experiment

Sprinkle some pepper in water and make it dance across the surface. Learn about the surface tension of water when you try this fun pepper and soap experiment with kids.

Magic Milk Experiment

Try this color-changing milk and soap experiment. Similar to water, the dish soap breaks the surface tension of the milk, allowing the food coloring to spread out.

Geometric Bubbles

Explore surface tension while you blow bubbles! Make your own homemade bubble solution too!

Paper Clips In A Glass

How many paper clips fit in a glass of water? It’s all to do with surface tension!

Skittles Experiment

Why don’t the skittles colors mix in water? Explore how surface tension of water makes effects the process. Also set this up with M&Ms.

Soap Powered Boat Experiment

Explore surface tension up close as kids observe firsthand how soap influences the movement of a small boat on the water’s surface.

Bonus Activity: Water Drop Painting

Not an experiment as such but still a fun activity that combines science and art. Paint with water drops using the principle of surface tension of water.

Free Printable Science Project Worksheets!

What is the scientific method?

The scientific method is a process or method of research. A problem is identified, information about the problem is gathered, a hypothesis or question is formulated from the information, and the hypothesis is put to test with an experiment to prove or disprove its validity. Sounds heavy…

What in the world does that mean?!? The scientific method should simply be used as a guide to help lead the process.

You don’t need to try and solve the world’s biggest science questions! The scientific method is all about studying and learning things right around you.

As kids develop practices that involve creating, gathering data evaluating, analyzing, and communicating, they can apply these critical thinking skills to any situation. To learn more about the scientific method and how to use it, click here.

Even though the scientific method feels like it is just for big kids…

This method can be used with kids of all ages! Have a casual conversation with younger kiddos or do a more formal notebook entry with older kiddos! Learn more about using the scientific method with kids.

Helpful Science Resources To Get You Started

Here are a few resources that will help you introduce science more effectively to your kiddos or students and feel confident yourself when presenting materials. You’ll find helpful free printables throughout.

• Best Science Practices (as it relates to the scientific method)
• Science Vocabulary
• All About Scientists
• Free Science Worksheets
• DIY Science Kits
• Science Tools for Kids
• Scientific Method for Kids
• Citizen Science Guide
• Join us in the Club

More Physical Science Activities

• Gravity Experiments
• Magnet Activities
• Simple Machine Projects
• Potential & Kinetic Energy
• Static Electricity
• Light Experiments

Printable Science Projects For Kids

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

• 90+ classic science activities  with journal pages, supply lists, set up and process, and science information.  NEW! Activity-specific observation pages!
• Best science practices posters  and our original science method process folders for extra alternatives!
• Be a Collector activities pack  introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?
• Know the Words Science vocabulary pack  includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!
• My science journal writing prompts  explore what it means to be a scientist!!
• Bonus STEAM Project Pack:  Art meets science with doable projects!
• Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics

Subscribe to receive a free 5-Day STEM Challenge Guide

~ projects to try now ~.

• About The Kid Should See This
• The TKSST Gift Guide
• Become a Member

Seven surface tension experiments – Physics Girl

This Physics Girl video highlights seven different surface tension experiments that you can easily try at home or in the classroom. Have any of these around? A plate, a glass, a penny, an index card, a paperclip, an eye dropper, a cup of coffee, dish soap, or some food coloring… and if you’re teaming up with an adult, get a pan and stove, too.

Surface tension is the energy, or work, required to increase the surface area of a liquid due to intermolecular forces. Since these intermolecular forces vary depending on the nature of the liquid (e.g. water vs. gasoline) or solutes in the liquid (e.g. surfactants like detergent), each solution exhibits differing surface tension properties.

Test those properties with a few experiments we’ve enjoyed before — milk fireworks and soap boat — and lots of experiments that we’ve never tried: Surface spheres, floating card, suddenly sinking paperclip, penny dropper, and the Leidenfrost Effect .

Next: Check out more of our favorite Physics Girl vids: The Stacked Ball Drop , How to make a Crazy Pool Vortex , and The Physics Behind a Curveball .

This Webby award-winning video collection exists to help teachers, librarians, and families spark kid wonder and curiosity. TKSST features smarter, more meaningful content than what's usually served up by YouTube's algorithms, and amplifies the creators who make that content.

Curated, kid-friendly, independently-published. Support this mission by becoming a sustaining member today .

🌈 Watch these videos next...

Wringing out water on the iss and ‘space oddity’, which is better: soap or hand sanitizer, what’s the right way to wash your hands.

June 25, 2015

Measure Surface Tension with a Penny

A soapy science activity from Science Buddies

By Science Buddies

Learn about the secrets of soap in this surprising surface tension-testing activity!

George Retseck

Key concepts Chemistry Molecules Surface tension

Introduction Have you ever noticed on a rainy day how water forms droplets on a window? Why does it do that instead of spreading out evenly over the whole surface? You might not guess it but this property of water is also related to washing dishes and doing the laundry. How? It all has to do with something called surface tension. Try this activity to learn more!

Background You have probably noticed that if you look at a surface outside on a rainy day or spill some water inside, the liquid tends to form droplets that stick up from a surface instead of spreading out into an even sheet. This occurs because water is made up of many tiny molecules that are all attracted to one another. Molecules in the middle of a drop of water are pulled evenly in all directions by all the nearby molecules. Those near the droplet’s surface, however, are pulled mostly inward by the water molecules below them. This creates "surface tension." The surface of the water droplet is held together by the attraction between molecules.

On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing . By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.

Now, think about washing dirty dishes or clothing. There will be lots of tiny little holes and cracks that water needs to get into to wash away dirt and grime, such as the spaces between the fibers of a shirt or between a plate and bits of dried food. In order for water to flow more easily into these small spaces, you need to decrease its surface tension. You can do this by adding soap, which is a surfactant (a material that decreases the surface tension of a liquid). In this activity you will see how soap decreases the surface tension of water by putting water droplets on top of a penny.

Medicine dropper or eyedropper

Glass, cup or small bowl

Dish towel or paper towel

Flat, level surface that can get wet, such as a kitchen counter

Paper and pencil or pen (optional)

Preparation

Place your penny on a flat, level surface that can get a little wet, such as a kitchen counter.

Fill a glass, cup or small bowl with tap water.

Fill the medicine dropper with water.

Now carefully add one drop of water at a time to the top of the penny. Hold the medicine dropper just above the top of the penny (not touching it) so each new drop has to fall a short distance before it merges with the drop on the penny. You can write down the number of drops you add if you like. How many drops of water do you think will fit on top of the penny? Watch the drop on top of the penny carefully as it grows. It should keep getting bigger and bigger until it touches the edges of the penny.

Keep adding drops (refill your medicine dropper as necessary) one at a time. How big does the drop on the penny get before it finally spills over the edges?

Once the drop spills over the penny’s edge, use a towel to completely dry off the penny and surrounding surface. How many drops of water were you able to add before the water ran over the penny’s sides?

Mix a small amount of dish soap with your tap water.

Now, repeat the experiment using soapy water. Do you think you will be able to add more drops or less before the liquid spills over the sides of the penny? Again, slowly add one drop at a time. How big does the drop of water on top of the penny get before it breaks and flows over the edges?

Extra : Try the experiment with different liquids or other things you can find in your kitchen. (Make sure you have an adult's approval to use any liquids before you handle them.) How do different soaps and detergents like hand soap or laundry detergent compare with one another? What about other liquids like milk or juice? Which ones make the biggest (or smallest) drops? With the most or least number of drops?

Extra : Try using something other than a penny to collect the droplets. What happens if you use different materials, such as the flat top of a small plastic bottle cap or a button?

[break] Observations and results You should find that plain tap water produces a much larger, stable drop of water on top of the penny than the soapy water does. This is because plain tap water has higher surface tension, so the surface is "stronger" and can hold together a larger drop. Adding soap lowers the water’s surface tension so the drop becomes weaker and breaks apart sooner. Making water molecules stick together less is what helps soaps clean dishes and clothes more easily.

More to explore Sticky Water , from Exploratorium Soap , from Exploratorium Measuring Surface Tension of Water with a Penny , from Science Buddies Surface Tension Science: Build a Raft Powered by Soap , from Scientific American Science Activities for All Ages! , from Science Buddies

This activity brought to you in partnership with Science Buddies

• Earth Science
• Physics & Engineering
• Science Kits
• Microscopes
• Science Curriculum and Kits
• About Home Science Tools

Science Projects > Physics & Engineering Projects > Water Experiments  

Water Experiments

Surface tension experiments.

Surface tension is one of the most important properties of water .

It is the reason that water collects in drops, but it’s also why plant stems can “ drink water ,” and cells can receive water through the smallest blood vessels.

You can test multiple surface tension experiments using just a few household items.

What You Do:

1. Start with a cup of water and some paperclips. Do you think a paperclip will float in the water? Drop one in the cup to find out. Since the paperclip is denser than the water, it will sink to the bottom of the cup.

Now find out if you can use surface tension to float the paperclip. Instead of dropping the paperclip into the cup, gently lay it flat on the surface of the water.

(This is tricky — it may help to place a piece of paper towel slightly bigger than the paperclip in the water. Then lay the paperclip on top of it. In a minute or so, the paper towel will sink, leaving the paperclip floating on top of the water.)

2. Even though the paperclip is still denser than the water, the strong attraction between the water molecules on the surface forms a type of ‘skin’ that supports the clip.

3. Now put a drop of dish soap in the water. This will bind with the water molecules, interfering with the surface tension .

The paper clip will sink. You can try floating other things on top of the water also – pepper floats well until you add dish soap. Can you find any other light items that will float?

Surface tension creates the ‘skin’ on top of the water, but it is also what causes water to stick together in drops.

Observe how these drops stick together by experimenting with water and a penny. All you need is a cup of water, a penny, and a medicine dropper .

First make a prediction: how many drops of water do you think you can fit on the top surface of the penny? Add one drop. After seeing how much room it takes, do you want to rethink your first prediction?

Now continue carefully adding drops until the water spills off the penny. Try this three times, recording the number of drops each time, and then find the average number of drops that can fit.

Surface tension is the reason you can fit so much water on the penny. The water molecules attract each other, pulling together so the water doesn’t spill.

Try this experiment with different-sized coins. Predict how many drops you can fit on a quarter compared with the penny.

For one final surface tension experiment, start with a full glass of water. Predict how many pennies you can add to the water without the glass overflowing. Gently add pennies one by one. Because of surface tension, the water will rise above the rim of the glass before it spills! Compare your original prediction with the number of pennies you were able to add.

Freezing Point

Have you ever wondered why rivers and lakes freeze in the winter, but oceans do not? In this experiment we will see that it is the presence of salt in the ocean that makes it less likely to freeze.

What You Need:

• 1-gallon freezer bag
• 1-quart freezer bag
• crushed ice
• thermometer

1. Fill the gallon freezer bag half full with crushed ice. Add one cup of salt and seal the bag. Put on some gloves and knead the ice and salt until the ice has completely melted.

2. Use the thermometer to record the temperature of the saltwater mixture. Even though the ice has melted, the temperature should be less than 32°F (0°C).

3. Now put about an ounce of water in the quart freezer bag. Seal the quart bag and then put it in the saltwater mixture in the larger bag. Seal the larger bag also and leave it until the water inside the quart bag freezes.

How did the water freeze when surrounded only by saltwater?

The salt broke apart the bonds between the water molecules in the ice, causing it to melt, but the temperature remained below the freezing point for pure water.

Salt (and other substances dissolved in water) will always lower the freezing point .

This is why water in the ocean rarely freezes.

• Find out more about salt water by making a Solar Purifier

More Water Projects:

•   Liquid Density
•   Hot Water: Convection Science
•  Water Wheel

Physics & Engineering

Welcome! Read other Physics & Engineering related articles or explore our Resource Center, which consists of hundreds of free science articles!

Shop for Physics Supplies!

Home Science Tools offers a wide variety of Physics products and kits. Find physics & engineering tools, equipment, STEM kits & more for kids and adults.

Related Articles

Homopolar Motor – Make a Spinning Wire Sculpture

In this experiment, we will make a homopolar motor! To make a simple motor (homopolar motor) that doubles as a work of art you will need three things – a battery, magnet, and wire. Use one of our neodymium magnets to power the spinning wire motor. What You Will Need:...

Solar Energy Matching Game

Print out this page on a sheet of heavy paper or cardstock. Kids can color the pictures and cut out the squares to make a matching game. Half of the squares show a way to use solar energy as an alternative to the picture shown on the other squares. Place all the...

Simple Spring Break Science Projects

Spring break is here! What will you do with your time off? Perhaps you're looking forward to a family vacation, or a few days of down time at home. Either way, find a quick and easy project that's sure to put a sparkle in the eye of any science lover, or win over a...

Sink or Float Worksheet

Use the Sink or Float Worksheet with the "Sink or Float?" science project to encourage kids to make predictions, perform tests, and record their results. This project is perfect for indoor discovery - especially in colder months! Put a towel under a large container of...

Physics Science Fair Projects

Find physics science fair project ideas about magnetism, electricity, energy and solar power, and more.

JOIN OUR COMMUNITY

Get project ideas and special offers delivered to your inbox.

• Physics Article
• To Find The Surface Tension Of Water By Capillary Rise Method

To Determine the Surface Tension of Water by Capillary Rise Method

Surface tension is the tendency of a liquid surface to shrink into the minimum surface area possible. The capillary rise method is one of the techniques to determine the surface tension of a liquid such as water. While experimenting with a capillary tube, it is observed that when a liquid rises in the tube, the weight of the liquid column is supported by the upward force of surface tension acting along the circumference of the points of contact. Let us learn about the experiment and the observations in detail.

To find the surface tension of water by capillary rise method.

Apparatus/ Materials Required

• Three capillary tubes of different radii
• A tipped pointer clamped in a metallic plate with a handle
• Travelling microscope
• Adjustable height stand
• A flat bottom open dish
• Thermometer
• Clean water in a beaker
• Clamp and a stand

The surface tension of water is given by the formula

where, r is the radius of cross-section, g is the acceleration due to gravity, ρ is the density of the liquid, h is the capillary rise, θ is the contact angle.

(a) Arranging the apparatus

• Place the adjustable height stand on the table and make its base horizontal by levelling the screws.
• Take dirt and grease-free water in an open dish with a flat bottom and put it on top of the stand.
• Take three capillary tubes of different radii.
• Clean the tubes and dry them and then clamp them to a metallic plate to increase the radius. Clamp a pointer after the third capillary tube.
• Clamp the horizontal handle of the metallic plate in a vertical stand so that the capillary tube and the pointer become vertical.
• Adjust the height of the metallic plate that the capillary tubes dip in the water in the open dish.
• Adjust the position of the pointer such that the tip touches the water surface.

(b) Measurement of capillary rise

• Calculate the least count of the travelling microscope for vertical and horizontal scales.
• Raise the microscope to a suitable height pointed towards the capillary tube with a horizontal axis.
• Focus the microscope on the first capillary tube.
• Make the horizontal crosswire touch the central part of the concave meniscus seen convex through the microscope
• Note the reading of the microscope on the vertical scale.
• Move the microscope horizontally and bring it in front of the second capillary tube.
• Lower the microscope and repeat steps 4 and 5
• Likewise, repeat steps 4 and 4 for the third capillary tube
• Lower the stand for the pointer tip to be visible.
• Move the microscope horizontally and bring it in front of the pointer.
• Lower the microscope and make the horizontal crosswire touch the tip of the pointer.

(c) Measurement of the internal diameter of the capillary tube

• Place the first capillary tube horizontally on the adjustable stand.
• Focus the microscope on the end dipped in water. A white circle with a green strip will be visible.
• Make the horizontal cross-wire touch the inner circle at point A.

Observation

The least count of the travelling microscope (L.C) = ….. cm.

Height of liquid rise

The internal diameter of the capillary

Calculation

Put the value h and r for each capillary tube separately and find the values of T using the following formula:

Find the mean value of the obtained T values as follows:

The surface tension of water at t °C is _____ dynes cm –1 .

1. Explain the relationship between surface tension and surface energy.

Answer: The relationship between surface tension and surface energy is given as follows:

Surface Energy = Surface tension × Change in area

2. Which side of the liquid surface has more pressure?

Answer: The pressure is more on the concave side of the free liquid surface.

3. What is capillary?

Answer : An open-ended tube with a fine bore is known as capillary.

4. Why should the liquid be free from grease?

Answer: Grease reduces the surface tension of the liquid.

5. What is the surface tension of water?

Answer: The surface tension of water is 7.275 × 10 –2 N-m –1 at 20 °C.

6. Why do you measure the internal diameter of the capillary tube in two mutually perpendicular directions?

Answer: It is done to take the mean to eliminate the error if the bore is not circular.

Stay tuned with BYJU’S to get the latest notification on CBSE along with CBSE syllabus, sample papers, marking scheme and more.

Put your understanding of this concept to test by answering a few MCQs. Click ‘Start Quiz’ to begin!

Select the correct answer and click on the “Finish” button Check your score and answers at the end of the quiz

Visit BYJU’S for all Physics related queries and study materials

Your result is as below

Request OTP on Voice Call

Leave a Comment Cancel reply

Your Mobile number and Email id will not be published. Required fields are marked *

Post My Comment

Thanks you for this practical

Register with BYJU'S & Download Free PDFs

Register with byju's & watch live videos.

• Skip to main content
• Skip to primary sidebar

Fun with Mama

Toddler and preschool activities

Written by Brenda • Mar 30, 2022 • Leave a Comment

5-Minute Paper Clip Surface Tension Experiment

Science experiments for kids are one of my favorite things to do at home with my kids. This surface tension experiment is a great way to explore and learn at the same time!

I love watching the wonder in their eyes as they do different science demonstrations and experiments.

However, sometimes I don’t have time to do a long experiment with them. That is why we recently did this paper clip surface tension science experiment while I was making dinner one night.

The kids were fascinated by the results, and I loved that they were learning science right there in my kitchen.

If you’re ready for even more science fun, check out my How To Grow Beans In A Bag – Bean in a Bag Science Experiment for Kids as well!

Easy Paper Clip Surface Tension Experiment

If you want a quick science lesson, it doesn’t get easier than this paperclip surface tension experiment! In less than five minutes, you can demonstrate how surface tension works to kids without getting into any complicated chemistry explanations.

Kids love repeating this simple experiment over and over. This surface tension experiment with paper clip is sure to be a hit.

Surface Tension Science for Kids

Surface tension is a surprising science fact. Water, even though many things sink in it, it has a strong bond between molecules The surface can hold some things on the water, and surface tension is why water beads into drops, instead of always spreading out flat and absorbing into every surface. Objects with a lower density than the surface tension bond of the water can float on top! Many insects can walk on the surface of the water.

While most metals are too dense to float on water, some are not! In this experiment kids will find out what small metal objects will float on the surface of water, and which will sink!

What You Need for this Experiment on Surface Tension

• Small metal objects (paperclip, coin, soda tab, nail, safety pin, etc.)
• Plastic cup (1 per group of kids doing the experiment)

How to Do the Paper Clip Surface Tension Science Experiment

This water surface tension experiment is easy to do and just takes 5 minutes of time. All ages are able to join in on the learning fun.

Fill the cup about halfway with water.

Discuss the properties of water molecules and the basics of surface tension.

Ask the kids which of the object they think will sink and if they think any might float. This is the hypothesis of the experiment.

Let the children gently place each object onto the surface of the water one at a time. Watch what happens to the objects.

In our experiment, everything sank except the metal paper clip and the soda tab. But, you might get different results!

Repeat the test for each object and then have the children discuss whether their original thoughts were proven right or disproven.

The children may want to take this experiment further by testing other objects to see if they can float on the surface of the water. Encourage this as that is scientific discovery at work!

If you want to test out if different liquids will have different results, let the kids try this experiment with milk, soda, and anything else that would be safe for little hands to touch and use!

Anytime that you can take a science experiment and combine it with analytics and critical thinking, it’s a win in terms of a scientific approach.

More Science Activities for Kids

• Fizzing Christmas Science Baking Soda Experiments
• Homemade Thermometer Science Experiment – Making a DIY STEM Thermometer
• Exploding Ziploc Bag Science Experiment for Kids

Brenda MacArthur is a STEM curriculum writer, STEM author, and STEM accessibility advocate. She founded the site STEAMsational.com in 2012 which offers hands-on STEM activities for kids and STEM lesson plans for teachers.

View all posts from this author

You May Also Enjoy These Posts:

Get easy and instant access to ALL of our printable activities and resources by joining the Fun With Mama printables club.

Get all the details and join here.

Reader Interactions

Leave a Comment Cancel reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed .

Have you grabbed the latest FREE printables?

Collection of Physics Experiments

Measurement of surface tension of liquid, experiment number : 2125, goal of experiment.

The goal of this experiment is to show how to determine a surface tension of a liquid by dripping.

Surface tension

Surface of a liquid behaves like a thin flexible membrane that tries to achieve an equilibrium state (state with minimum energy). With increasing surface, the energy of the surface layer increases. The surface of the liquid hence tries to take the smallest and smoothest area.

The value of surface tension decreases with increasing temperature.

Surface tension measurement

One of the methods to measure surface tension of a liquid is to let the liquid drip.

Liquid in a capillary tube forms drops at the bottom of the tube. The drops will gradually grow and, when they reach a sufficient size, they will separate from the liquid.

The gravitational force acts upon a drop with mass m :

The drop is held at the end of the capillary tube by surface forces. The net force of these forces acts upwards and its magnitude is calculated from relationship

where σ is the surface tension of the liquid, l is the circumference of the drop dripping from the capillary and d its diameter.

The drop will separate from the tube when the gravitational force is greater than the net force of the surface forces. Therefore:

After substituting from the equations above:

The surface tension is then calculated from the relationship

Using this formula, it would be possible to determine the surface tension. The accuracy of this measurement is negatively affected by the fact that only a part of the drop is separated from the tube when the drop drips; part of it stays on the end of the capillary. Before separating, the drop is narrowed and its diameter is smaller than d . Therefore, the dripping method is used mainly as a reference method. If we work with the same capillary, the diameter of the narrowed drop is approximately the same with all wetting liquids.

We use two different liquids in this experiment. We measure the surface tension σ 1 of one liquid; we must know the surface tension σ 2 of the second liquid (which can be looked up). We then determine the ratio of the surface tensions of these liquids

First we determine the mass of one drop of each liquid (weigh more drops and divide the result by the number of drops). We substitute these masses m 1 and m 2 into the relationship

You can find the solved task here:   Oil Pipetting .

liquid with unknown surface tension we want to measure

liquid with surface tension we know (e.g. water)

laboratory stand

cork with a hole (of a size to fit the capillary and the funnel firmly into it)

container into which we drop the measured liquid

laboratory scales

thermometer

Note: If you do not have these tools, you can use a capillary or pipette to drip the liquid (see Technical notes).

Fig 1: Tools for dripping

Insert the funnel in one side of the hole in the cork and the capillary in the other. Fasten the cork in the laboratory stand.

Weigh the empty container which you later use to catch the drops.

Measure the temperature of both liquids.

Pour the liquid in the funnel.

Drip 100 drops (if we want to measure more accurately, we can drip more drops).

Weigh the container with 100 drops.

Determine the mass of 100 drops and then the mass of one drop.

Use the same procedure to determine the mass of one drop of water (second liquid).

Calculate the surface tension of the liquid from the relationship

Sample result

We made the measurements with water, alcohol and kerosene. We weighed the container and let all the liquids drip into it.

The temperature of both liquids was 20 °C.

We used water as the reference liquid with known surface tension ( σ 1  = 72.75·10 −3  N/m at temperature 20 °C).

Table 1 summarizes the mass of 100 drops of each liquid m 100 , the mass of one drop of each liquid m 1 and the surface tension σ .

For comparison, the table values for alcohol and kerosene at 20 °C (Czech source: Converter ):

Technical notes

We can use a pipette or a capillary to perform this experiment. Draw the measured liquid into the pipette or the capillary, block the upper end with your finger and let the liquid drip. We can influence the drip rate by pushing the top of the pipette.

Buggy and Buddy

Meaningful Activities for Learning & Creating

November 4, 2013 By Chelsey

Science Experiments for Kids: Exploring Surface Tension

We always enjoy all types of  science experiments for kids ! Our latest science experiment is all about exploring the surface tension of water and other liquids. This simple experiment for kids really intrigued my 5 year old and inspired her to come up with all kinds of ideas!

Follow our Science for Kids Pinterest board!

Whenever I  present my kids with  science experiments, my main goal   is to inspire them to make predictions and critically think about the world around them.  Exploring the surface tension of water and other liquids really motivated Lucy to come up with her own predictions and ideas!  (This post contains affiliate links.)

Materials for Exploring Surface Tension

• Cooking oil (We used canola oil.)

1. Use the eye dropper to place a few drops of water on some wax paper. Observe the drops closely. What do you notice?

2. Use another eye dropper to place some drops of cooking oil near the water drops. Compare the cooking oil to the water. How are they the same? How are they different?

3. Look closely at other liquids like rubbing alcohol on the wax paper. Compare and contrast all the liquids.

4. Try poking the water drop with a clean toothpick. What happens?

5. Now poke the water drop with a  toothpick that has been dipped in dish soap. What happens? Why do you think this happened?

After completing the previous steps, Lucy enjoyed trying out her own ideas. She tried placing drops of oil on top of water drops and tried mixing them together. Then she tried poking the different liquid drops with clean and soapy toothpicks. She was so intrigued!

What’s Going On?

The water drop on the wax paper looks kind of like there’s a skin around it. When you poke it with a clean toothpick, nothing happens, but, when you poke it with a soapy toothpick, the water spreads out.

Drops of water stick to each other. That’s why the surface of the water drops appear to have a skin-like layer on them.  This is called surface tension. Soap decreases the water’s surface tension causing it to spread out.

Want to Go Even Further?

Related activities to extend the learning for various ages.

• Here’s another experiment having to do with the surface tension of water~ Paperclips in Water .
• Try a similar experiment. See how many drops of water can sit on the surface of a penny using a dropper. Was it what you expected?
• Observe how the drops of other liquids look on the wax paper.

Be sure to check out STEAM Kids book and ebook for even more creative STEM and STEAM ideas!

• PRO Courses Guides New Tech Help Pro Expert Videos About wikiHow Pro Upgrade Sign In
• EDIT Edit this Article
• EXPLORE Tech Help Pro About Us Random Article Quizzes Request a New Article Community Dashboard This Or That Game Happiness Hub Popular Categories Arts and Entertainment Artwork Books Movies Computers and Electronics Computers Phone Skills Technology Hacks Health Men's Health Mental Health Women's Health Relationships Dating Love Relationship Issues Hobbies and Crafts Crafts Drawing Games Education & Communication Communication Skills Personal Development Studying Personal Care and Style Fashion Hair Care Personal Hygiene Youth Personal Care School Stuff Dating All Categories Arts and Entertainment Finance and Business Home and Garden Relationship Quizzes Cars & Other Vehicles Food and Entertaining Personal Care and Style Sports and Fitness Computers and Electronics Health Pets and Animals Travel Education & Communication Hobbies and Crafts Philosophy and Religion Work World Family Life Holidays and Traditions Relationships Youth
• Browse Articles
• Learn Something New
• Quizzes Hot
• Happiness Hub
• This Or That Game
• Train Your Brain
• Explore More
• Support wikiHow
• About wikiHow
• Log in / Sign up
• Education and Communications

How to Measure Surface Tension

Last Updated: November 4, 2022 Fact Checked

This article was co-authored by Bess Ruff, MA . Bess Ruff is a Geography PhD student at Florida State University. She received her MA in Environmental Science and Management from the University of California, Santa Barbara in 2016. She has conducted survey work for marine spatial planning projects in the Caribbean and provided research support as a graduate fellow for the Sustainable Fisheries Group. There are 11 references cited in this article, which can be found at the bottom of the page. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 161,146 times.

Surface tension refers to the ability of a liquid to resist the force of gravity. For example, water forms droplets on a table because the water molecules at the surface group together against the force of gravity. [1] X Trustworthy Source Science Buddies Expert-sourced database of science projects, explanations, and educational material Go to source Surface tension is what allows a denser object, such as an insect, to be able to float on the water's surface. Surface tension is measured by the amount of force (N) exerted on a unit such as length (m) or the amount of energy of a measured area. These are measured as Newton per meter (or N/meter). [2] X Trustworthy Source Science Buddies Expert-sourced database of science projects, explanations, and educational material Go to source The forces that water molecules exert on each other, or cohesive forces, cause the tension and are responsible for the shape of water (or other liquid) drops. You can measure surface tension with a few household items and a calculator.

Measuring Surface Tension with a Balance Beam

• The force will be calculated at the end of the experiment.
• Measure the length of the needle in meters using a ruler before starting the experiment.

• Mark the center of the material to be used for your beam (straw, plastic ruler) and drill or poke a hole through it; this will be the fulcrum point (the point that allows the beam to rotate freely). If you are using a plastic straw you can just poke a pin or nail right through it.
• Drill or poke a hole at each end of the beam ensuring that they are the same distance from the middle. Thread a string through each hole to serve as holders for the balance dishes. Make sure that there is 1 string for each hole at either end.
• Rest the nail horizontally between two stacks of books so that the center beam can rotate freely.

• Hang the box or dish from one end of the beam. Poke small holes in the sides of the dish and thread the string through to hold up the dish.

• This is called counterbalancing. The clay does not affect the calculations because it is balancing out the beam.

• Make sure the string holding the needle in place remains taut once the needle is on top of the water.

• Count out a number of pins or drops of water and weigh them.
• Determine the individual weight of each drop or pin by dividing the total weight by the number of pins or water drops.
• For example, let’s say 30 pins weigh 15 grams: 15/30 = 0.5. Each pin weighs 0.5 grams.

• Count the number of pins or drops of water needed to remove the counterweight from the water's surface.
• Record each reading.
• Repeat the exercise several times (5 or 6) for more accurate readings.
• Calculate an average of the results by adding the total number of pins needed in each trial and dividing that by the total number of trials.

• Multiply the number of pins added to the dish by the weight of each pin. For example, 5 pins at 0.5 g/pin = 5 x 0.5 = 2.5 g.
• Multiply the amount of grams by the conversion factor 0.00981 N/g: 2.5 x 0.00981 = 0.025 N.

• Continuing our example, let’s say the needle was 0.025 m long. Plugging the variables into the equation yields: S = F/2d = 0.025 N/(2 x 0.025) = 0.05 N/m. The surface tension of the liquid is 0.05 N/m.

Measuring Surface Tension with Capillary Action

• The height the liquid rises can be used to calculate the surface tension of that liquid.
• Cohesion causes water to form bubbles or droplets on a surface. When a liquid is in contact with air, the molecules feel attractive forces towards each other and make a bubble on the surface.
• Adhesion causes the meniscus that is seen in liquids when they cling to the sides of a glass. It is the concave shape at the top of the liquid seen at eye level. [7] X Research source
• An example of capillary action is watching water rise in a straw placed in a cup of water.

• When working through this equation, make sure all of your units are in the proper metric form: density in kg/m 3 , height and radius in meters, and gravity in m/s 2 .
• If the density of the liquid is not given, you can look it up in a reference book or calculate it using the equation density = mass/volume.
• The unit for surface tension is one newton per meter (N/m). A Newton is equal to 1 kg-m/s 2 . To work out the units on your own, simply solve the equation with just units. S = kg/m 3 * m * m/s 2 * m. Two of the meter units cancel out two of the per meter units and you are left with 1 kg-m/s 2 /m or 1 N/m.

• If you repeat this with different liquids, make sure the dish is thoroughly cleaned and dried before adding the next liquid. Alternatively, just use separate dishes for each liquid.

• To measure the radius, simply place a ruler across the top of the tube and determine the diameter. Divide the diameter by 2 and you have the radius.
• You can buy these tubes online or from a hardware store.
• It can be difficult to accurately measure small changes in the height the liquid will rise in a straw or wide tube. As the height to which the water will rise is inversely proportional to the diameter of the tube (narrower tube = higher rise) this experiment is much easier to do with a narrow transparent capillary tube. These can be purchased at low cost online, but confirm the inside diameter is provided (typically around 1mm-1.2mm) and both ends are open. As these are fragile and made of glass, ensure care when handling them.

• For example, let’s say we are measuring the surface tension of water. Water has a density around 1000 kg/m 3 (we will use approximate values in this example). [12] X Research source The variable g is always 9.8 m/s 2 . The radius of the tube is .029 m and the water rises 0.0005 m. What is the surface tension of the water?
• Plugging the variables into the equation yields: S = (ρhga/2) = (1000 x 9.8 x 0.029 x 0.0005)/2 = 0.1421/2 = 0.071 J/m 2 .

Measuring Relative Surface Tension with a Penny

• Make sure the penny is completely clean and dry before beginning the experiment. If there are other liquids on the penny, the experiment will not be accurate.
• This experiment does not allow you to calculate surface tension, but just determine surface tensions of different liquids relative to each other.

• Write down how many drops it takes for the liquid to flow over the side of the penny.

• Try mixing a little bit of dish soap to the water and dropping again to see if the surface tension changes.

• Substances with a higher surface tension will have more drops on the penny than substances with a lower surface tension.
• The dish soap lowers the surface tension of the water, using fewer drops to fill the penny.

Community Q&A

Things You'll Need

• Straw, plastic ruler or other stiff rod
• Aluminum foil
• Modeling clay or other similar material
• Long needle or nail for fulcrum
• Paper clip or needle to submerge into water
• Books or other material of equal weight to support the balance beam
• Small container
• Eye dropper, pipette or pins
• Postal scale or other small weighing device
• Shallow dish

You Might Also Like

• ↑ http://www.sciencebuddies.org/science-fair-projects/project_ideas/Chem_p021.shtml#background
• ↑ http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p012.shtml#background
• ↑ https://csef.usc.edu/History/2015/Projects/J1710.pdf
• ↑ http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p012.shtml#procedure
• ↑ https://www.teachengineering.org/view_lesson.php?url=collection/duk_/lessons/duk_surfacetensionunit_lessons/duk_surfacetensionunit_less2.xml
• ↑ https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Physical_Properties_of_Matter/States_of_Matter/Properties_of_Liquids/Capillary_Action
• ↑ https://pressbooks.uiowa.edu/clonedbook/chapter/cohesion-and-adhesion-in-liquids-surface-tension-and-capillary-action/
• ↑ https://chem.libretexts.org/Courses/Oregon_Institute_of_Technology/OIT%3A_CHE_202_-_General_Chemistry_II/Unit_7%3A_Intermolecular_and_Intramolecular_Forces_in_Action/7.1%3A_Surface_Tension%2C_Viscosity%2C_and_Capillary_Action
• ↑ http://www.engineeringtoolbox.com/water-density-specific-weight-d_595.html
• ↑ https://www.scientificamerican.com/article/measure-surface-tension-with-a-penny/
• ↑ https://www.sciencebuddies.org/science-fair-projects/project-ideas/Chem_p021/chemistry/measuring-surface-tension-of-water-with-a-penny

About This Article

To measure surface tension using the capillary method, fill a shallow dish with 1 inch of water. Measure the radius of a clear tube, then place the tube in the water and measure how high the water in the tube rises above the water in the container. Plug the measured value into your equation to calculate the surface tension. For more information on measuring surface tension from our Environmental Science reviewer, including how to calculate relative tension with a penny, keep reading. Did this summary help you? Yes No

• Send fan mail to authors

Reader Success Stories

Mar 16, 2017

Did this article help you?

Nov 19, 2016

Ian Nachamba

Jul 1, 2016

Mar 19, 2019

Krish Chodhari

Jul 28, 2017

Featured Articles

Trending Articles

Watch Articles

• Terms of Use
• Privacy Policy
• Do Not Sell or Share My Info
• Not Selling Info

wikiHow Tech Help Pro:

Level up your tech skills and stay ahead of the curve

Your browser is not supported

Sorry but it looks as if your browser is out of date. To get the best experience using our site we recommend that you upgrade or switch browsers.

Find a solution

• Skip to main content
• Skip to navigation

• Back to parent navigation item
• Primary teacher
• Secondary/FE teacher
• Early career or student teacher
• Higher education
• Curriculum support
• Literacy in science teaching
• Periodic table
• Interactive periodic table
• Climate change and sustainability
• Resources shop
• Collections
• Remote teaching support
• Starters for ten
• Screen experiments
• Assessment for learning
• Microscale chemistry
• Faces of chemistry
• Classic chemistry experiments
• Nuffield practical collection
• Anecdotes for chemistry teachers
• On this day in chemistry
• Global experiments
• PhET interactive simulations
• Chemistry vignettes
• Context and problem based learning
• Journal of the month
• Chemistry and art
• Art analysis
• Pigments and colours
• Ancient art: today's technology
• Psychology and art theory
• Art and archaeology
• Artists as chemists
• The physics of restoration and conservation
• Ancient Egyptian art
• Ancient Greek art
• Ancient Roman art
• Classic chemistry demonstrations
• In search of solutions
• In search of more solutions
• Creative problem-solving in chemistry
• Solar spark
• Chemistry for non-specialists
• Health and safety in higher education
• Analytical chemistry introductions
• Exhibition chemistry
• Introductory maths for higher education
• Commercial skills for chemists
• Kitchen chemistry
• Journals how to guides
• Chemistry in health
• Chemistry in sport
• Chemistry in your cupboard
• Chocolate chemistry
• Adnoddau addysgu cemeg Cymraeg
• The chemistry of fireworks
• Festive chemistry
• Education in Chemistry
• Teach Chemistry
• On-demand online
• Live online
• Selected PD articles
• PD for primary teachers
• PD for secondary teachers
• What we offer
• Chartered Science Teacher (CSciTeach)
• Teacher mentoring
• UK Chemistry Olympiad
• Who can enter?
• How does it work?
• Resources and past papers
• Top of the Bench
• Schools' Analyst
• Regional support
• Education coordinators
• RSC Yusuf Hamied Inspirational Science Programme
• RSC Education News
• Supporting teacher training
• Interest groups

• More navigation items

Detergents, soaps and surface tension

In association with Nuffield Foundation

• No comments

Various experiments to observe the effects of detergents and soaps on the surface tension of purified and hard water

A fine insoluble powder, such as talcum powder, is sprinkled on a clean water surface in a beaker, a drop of detergent or soap solution added to the centre, and the effect observed as the surface tension of the water is changed. This can be repeated with other powders after cleaning the beaker and using fresh water samples. A needle can be carefully floated on a clean water surface and the effect of adding detergent or soap observed. Finally the same experiments can be repeated using samples of hard water to compare the effects.

This is a series of quick, simple, class experiments which can be extended or shortened as desired. Each experiment should take no more than two minutes, though the cleaning of the beaker between experiments may take up more time than expected. If a full range of experiments is desired, the time taken could amount to 30 minutes, but this may not be justified in terms of the learning objectives concerned.

• Beaker (250 cm 3 )
• Glass stirring rod
• Clean sewing needle (note 1)

Apparatus notes

• The sewing needle should be a fine needle, and for safety issued to students with the pointed end inserted into a piece of card bearing a safety warning about handling the needle.
• Talcum powder, in pepper pot or similar dispenser
• Other powders (see technical notes)
• Liquid detergent in a dropping bottle
• Liquid soap in a dropping bottle
• Access to a supply of purified water (distilled or deionised), about 1 dm 3  per working group
• Access to a supply of hard water

Health, safety and technical notes

• Read our standard health and safety guidance
• Other powders – Any powders used other than talcum powder, such as lycopodium powder or carbon powder, should be subject to a risk assessment. Lycopodium powder is a potential allergen.
• Liquid detergent – Any washing-up liquid or multipurpose detergent will suffice.
• Liquid soap - Genuine liquid soap or soap flakes from which the liquid can be made, is increasingly difficult to obtain. Wanklyn’s and Clarke’s soap solutions should still be available from chemical suppliers. Lux soap flakes are ideal for making liquid soap if you can source them. Granny’s Original and other non-branded soap flakes work fine but need to be used in solution as soon as they are made. They do not form a stable emulsion and precipitate out overnight. Note that most liquid hand washes are based on the same detergents as washing-up liquids and do not contain soap. To obtain soap solution from soap flakes – dissolve soap flakes (or shavings from a bar of soap) in ethanol – use IDA (Industrial Denatured Alcohol) (HIGHTLY FLAMMABLE, HARMFUL) – see CLEAPSS Hazcard HC040a and CLEAPSS Recipe Book RB000. Do not dilute with water.
• Hard water – A supply of hard water can be made by stirring solid calcium sulfate into a large volume of tap water, allowing to stand for some time then, after the undissolved solid has settled out, decanting the clear solution into a container suitable for students to collect their samples as required. Label as ‘Hard Water’. Allow about 1 dm 3  for each working group in the class.
• Half fill the beaker with purified water.
• Sprinkle the water surface carefully with a fine layer of powder.
• Add one drop only of detergent in the middle of the water surface. Observe what happens. Does the talcum powder stay on the surface, or does it sink?
• Clean the beaker thoroughly, half-fill again with purified water, and repeat steps two and three using a drop of liquid soap instead of detergent. Compare what happens to what happened in the previous experiment.
• Repeat steps three   and four, only this time use hard water instead of purified water. Are the results different from those obtained with purified water? If so, in what ways?
• Other powders may be available to test instead of talcum powder, to see whether the type of powder makes any difference. If you do test any of these, what differences do you find?
• Again using a clean beaker with purified water, try to float a fine sewing needle on the surface by carefully lowering it into the beaker, avoiding breaking the surface with your fingers, and dropping it from as close above the surface as possible. Once you have a needle floating, add a small drop of detergent to the water, but away from the needle. What happens?

Teaching notes

This series of brief experiments on the surface tension of water, and the effects of detergents and soaps on this, can serve as an introduction to the phenomenon of surface tension, with a discussion of results leading into simple theory. Alternatively, it could be used to illustrate prior teaching of the topic, leading to discussion of what is happening when detergents and soaps are added, including the differences found with hard water.

A diagram of the forces between water molecules at the surface and centre of a liquid.

There is a net force of attraction between the molecules of water (or any other liquid) holding the molecules together. For a molecule in the middle of the liquid, these forces, acting equally in all directions, more or less balancing out. For a molecule in the surface layer of the liquid, the forces do not balance out, and all the molecules in the surface layer are pulled towards each other and towards the bulk of the liquid. This brings these molecules closer to their neighbours until increasing forces of repulsion create a new balance, and gives rise to the phenomenon of surface tension.

When an object falls onto the surface, it has to push the water molecules apart. If the effect of the weight of the object is insufficient to match the attractive forces between molecules in the surface layer, the object will not enter the surface. Careful observation of the floating needle will show that the water surface is bent down under the weight of the needle, the surface tension causing it to behave as if the needle was supported by a flexible skin.

A diagram of the forces enabling a needle to float on water

Molecules of most detergents and soaps are long chain hydrocarbon molecules with an ionic group at one end, usually carrying a negative charge, thus making it an anion. This charge is balanced by the opposite charge of a soluble cation, for example Na + . The long hydrocarbon chains do not interact well with water molecules, and many of them are effectively ‘squeezed out’ to the interfaces between the water and the air or the glass sides of the beaker. The effect of these molecules on the water surface is to considerably weaken the forces between water molecules there, thus lowering the surface tension.

A diagram of a detergent or soap molecule, which is responsible for breaking down surface tension

When the drop of detergent is added to the powdered surface, the initial effect is to draw the powder back to the edges very rapidly as the detergent molecules form their own surface layer with a lower surface tension than the water. As the detergent gradually mixes with the water, the powder begins to sink, and a needle will now pass through the surface with ease under its own weight. However, if lycopodium powder is used, which is less dense than water, it remains at the edges. Other powders may clump into nodules if they are not wetted by the detergent solution.

A diagram showing detergent molecules in a beaker of water, some lining the surfaces and other forming clumps

In hard water there is a significant concentration of calcium, Ca 2+ , and/or magnesium, Mg 2+ , cations. These cations form an insoluble compound with soap anions, so instead of forming a surface layer, they are precipitated out, leaving the surface tension largely unchanged.

2COO − (aq) + Ca 2+ (aq) → (COO) 2 Ca(s)

However, the calcium and magnesium salts of many detergent molecules are soluble, so detergents lower the surface tension of hard water.

Additional information

This is a resource from the  Practical Chemistry project , developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany  Practical Physics  and  Practical Biology . 

© Nuffield Foundation and the Royal Society of Chemistry

• 14-16 years
• Practical experiments
• Practical skills and safety
• Investigation
• Properties of matter
• Applications of chemistry

Related articles

What’s the world’s strongest glue?

2024-07-19T05:32:00Z By Kit Chapman

Find out about the world’s stickiest glue and how adhesives bond things together

How to teach titration post-16

2024-07-08T05:32:00Z By Jo Haywood

Tips for teaching practical titration techniques and the underlying theory

Help learners master equilibrium and reversible reactions

2024-06-24T06:59:00Z By Emma Owens

Use this poster, fact sheet and storyboard activity to ensure your 14–16 students understand dynamic equilibrium

No comments yet

Only registered users can comment on this article., more experiments.

‘Gold’ coins on a microscale | 14–16 years

By Dorothy Warren and Sandrine Bouchelkia

Practical experiment where learners produce ‘gold’ coins by electroplating a copper coin with zinc, includes follow-up worksheet

Practical potions microscale | 11–14 years

By Kirsty Patterson

Observe chemical changes in this microscale experiment with a spooky twist.

Antibacterial properties of the halogens | 14–18 years

By Kristy Turner

Use this practical to investigate how solutions of the halogens inhibit the growth of bacteria and which is most effective

• Contributors
• Email alerts

Site powered by Webvision Cloud

Sciencing_Icons_Science SCIENCE

Sciencing_icons_biology biology, sciencing_icons_cells cells, sciencing_icons_molecular molecular, sciencing_icons_microorganisms microorganisms, sciencing_icons_genetics genetics, sciencing_icons_human body human body, sciencing_icons_ecology ecology, sciencing_icons_chemistry chemistry, sciencing_icons_atomic & molecular structure atomic & molecular structure, sciencing_icons_bonds bonds, sciencing_icons_reactions reactions, sciencing_icons_stoichiometry stoichiometry, sciencing_icons_solutions solutions, sciencing_icons_acids & bases acids & bases, sciencing_icons_thermodynamics thermodynamics, sciencing_icons_organic chemistry organic chemistry, sciencing_icons_physics physics, sciencing_icons_fundamentals-physics fundamentals, sciencing_icons_electronics electronics, sciencing_icons_waves waves, sciencing_icons_energy energy, sciencing_icons_fluid fluid, sciencing_icons_astronomy astronomy, sciencing_icons_geology geology, sciencing_icons_fundamentals-geology fundamentals, sciencing_icons_minerals & rocks minerals & rocks, sciencing_icons_earth scructure earth structure, sciencing_icons_fossils fossils, sciencing_icons_natural disasters natural disasters, sciencing_icons_nature nature, sciencing_icons_ecosystems ecosystems, sciencing_icons_environment environment, sciencing_icons_insects insects, sciencing_icons_plants & mushrooms plants & mushrooms, sciencing_icons_animals animals, sciencing_icons_math math, sciencing_icons_arithmetic arithmetic, sciencing_icons_addition & subtraction addition & subtraction, sciencing_icons_multiplication & division multiplication & division, sciencing_icons_decimals decimals, sciencing_icons_fractions fractions, sciencing_icons_conversions conversions, sciencing_icons_algebra algebra, sciencing_icons_working with units working with units, sciencing_icons_equations & expressions equations & expressions, sciencing_icons_ratios & proportions ratios & proportions, sciencing_icons_inequalities inequalities, sciencing_icons_exponents & logarithms exponents & logarithms, sciencing_icons_factorization factorization, sciencing_icons_functions functions, sciencing_icons_linear equations linear equations, sciencing_icons_graphs graphs, sciencing_icons_quadratics quadratics, sciencing_icons_polynomials polynomials, sciencing_icons_geometry geometry, sciencing_icons_fundamentals-geometry fundamentals, sciencing_icons_cartesian cartesian, sciencing_icons_circles circles, sciencing_icons_solids solids, sciencing_icons_trigonometry trigonometry, sciencing_icons_probability-statistics probability & statistics, sciencing_icons_mean-median-mode mean/median/mode, sciencing_icons_independent-dependent variables independent/dependent variables, sciencing_icons_deviation deviation, sciencing_icons_correlation correlation, sciencing_icons_sampling sampling, sciencing_icons_distributions distributions, sciencing_icons_probability probability, sciencing_icons_calculus calculus, sciencing_icons_differentiation-integration differentiation/integration, sciencing_icons_application application, sciencing_icons_projects projects, sciencing_icons_news news.

• Share Tweet Email Print
• Home ⋅
• Science Fair Project Ideas for Kids, Middle & High School Students ⋅

How to Demonstrate Surface Tension with a Paperclip and Water for a Science Experiment

Three Ways That Polarity of Water Molecules Affect the Behavior of ...

The surface tension of water describes how molecules on the surface of the liquid attract each other. The surface tension of water allows objects of greater density to be supported on the surface of the water. The attraction of a molecule to itself is called cohesion, and attraction between two different molecules is called adhesion. The paperclip floating on the surface of water demonstrates to your children how the surface tension of water works. Indeed, surface tension is what allows small insects to walk on the surface of water -- or what allows dust and leaves to float on the surface of water. This property, in conjunction with cohesion, is what allows the surface portion of a liquid to form drops, such as water drops.

Fill a bowl, glass or beaker with water.

Float a small piece of paper towel on the surface of the water.

Place the paperclip on top of the paper towel.

Push the sides of the paper towel carefully down into the water until the paper towel is no longer touching the paperclip.

Remove the paper towel carefully from the water. The paperclip should easily remain floating on the surface of the water unless it is disturbed or bumped.

Mix some soap with water in a container.

Add a couple drops of soapy water to the surface of the water using a dropper. Do this where the paperclip is floating. But be careful to add it to the water away from the paperclip. The soapy water should break the surface tension of the water, causing the paperclip to fall to the bottom of the container. If it doesn't work immediately, give it a few seconds or add a few more drops of soapy water.

Ask your child or student to explain why the paperclip floats on water (since it is denser than water). This is also a way to help your young children become or stay interested in science.

Ask your children or students why they think soapy water caused the paperclip to fall to the bottom. (Hint: It is because soap is a surfactant, and that reduces the surface tension of water.)

Things You'll Need

• Water beading on a freshly waxed car forms a sphere because of the water's surface tension.

The separation of oil and water is caused by several different properties of the liquids, including the differences in the surface tension of the liquids -- called "interface tension."

Related Articles

Three ways that polarity of water molecules affect..., which lipids are water soluble, what is the difference between permeable & impermeable, magic science tricks for kids, how to prepare supersaturated salt water solutions, how does detergent break surface tension, what is in corn syrup that makes a bubble, how to float an egg in water, how to calculate buoy floatation in the water, how are river rocks formed, are ions hydrophobic or hydrophilic, density experiments for elementary, test your knowledge on middle school science, list of plants that live in the water, how to separate oil & water layers, water bottle science experiments, water polarity experiments, what color would a tester ph paper turn if is dipped..., molecular activity of water vs. oil.

• Elmhurst College: Floating Objects
• The separation of oil and water is caused by several different properties of the liquids, including the differences in the surface tension of the liquids -- called "interface tension."

About the Author

This article was written by the CareerTrend team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more about CareerTrend, contact us [here](http://careertrend.com/about-us).

Photo Credits

Hemera Technologies/PhotoObjects.net/Getty Images

Find Your Next Great Science Fair Project! GO

How to Explain Surface Tension to Kids?

Did your child ever fill a glass of lemonade so full, you thought it would spill? But then it didn’t? That’s what we call surface tension. But how to explain surface tension to kids ? A question not so easily answered.

Experts say, kids are like a sponge, they absorb every information that you throw at them. Studies suggest that a child’s brain is twice as active as an adult by age three. This is because their brain is more flexible and has more connections per brain cell than an average adult.

Children learn by playing , through fun activities, and experimentation. If you put in a bit of effort and try to explain things through activities and experiments, your kids will more easily retain the lesson.

A few years ago, all of this was just something that I had heard. Reality struck when my son turned six and started asking all sorts of questions about things happening around him.

I had to answer him, and drab science books weren’t cutting it. That’s when I remembered about DIY experiments. I started using this method for teaching everything.

Pepper and Soap

Recently, he saw a video on the internet where pepper sprinkled on the surface of the water in a bowl dispersed when someone dipped a soapy finger in it.

Hee did the same at home and was amazed by the result. As usual, the barrage of questions aimed at me was relentless, and I was unprepared.

After searching around on the internet, I had my answer: surface tension. But the concept seemed challenging to explain with mere words. Read below, and let me know if you understand.

Surface Tension: The Theory

Before we go ahead, let’s first understand the “concept” behind surface tension ourselves. Water molecules (or any liquid for that matter) attract each other. That is why liquids don’t just fly off like gases.

But the poor surface molecules don’t have others to cling to, like the rest of them on the inside. So, they are attracted even more strongly to the ones nearest to them (directly below them).

Because they are trying so hard to stick with the rest of the liquid, the surface molecules create a “barrier” that doesn’t allow things to penetrate and fall inside the liquid. This phenomenon is what scientists call “surface tension.”

Well, now that you know the theory, you might understand why I decided to use the experimentation route with my boy to explain the concept.

Below are the experiments that I tried. I hope they will help you too!

Experiment 1: The Ultimate Pepper And Soapy Finger

This experiment was the simplest one for him. You only need simple ingredients, which you will probably have in your kitchen pantry.

Ingredients you will need:

• A glass of water
• Pepper powder
• Liquid soap

Steps to follow:

• Fill the bowl with water. The water should be at least one finger deep.
• Sprinkle some pepper powder on top of the water. For a spectacular view, add a little extra powder.
• Dip the tip of your child’s finger in the liquid soap.
• Now ask your child to touch the surface of the water with a soapy finger.
• See the magic happening!

What did you observe?

You must have observed that pepper moved away from the finger and gathered near the edge of the bowl. All this happened because of the surface tension.

When your child inserts the soapy finger in the bowl, it breaks the surface tension near the finger. However, the surface tension remains the same near the edges. Hence, as the molecules near the finger start moving towards the edges, they carry along with the pepper powder.

While all this was happening in the bowl, you will also observe that some pepper has sunk at the bottom.

This is because the tension in the middle broke, and since the density of pepper is more than water, it sunk.

Experiment 2: Water on Penny

If you want to convey to your kids how water molecules hold each other, this is the perfect experiment.

• Squirt bottle filled with water.
• Put the penny on a flat surface or a tabletop.
• Use a squirt bottle to drop water droplets on a penny one by one.
• Now ask your kids to stop when you see that the penny cannot hold any more water.
• Observe the water dome on top of the penny (from the side and not from the top).

You observed that a small dome of water formed on top of the penny. This is because the water molecules hold each other so tightly that they don’t want to separate.

They cling to each other because there is no other water molecule to hold. They hold each other so tightly that skin seems to form on the surface.

If you sprinkle some pepper powder on top, you will observe that it did not sink because of their skin layer. This is the surface tension that prevents pepper from sinking or water from penny from spilling all over.

Of course, if your child keeps adding water droplets, a time will come when the water molecules will no longer be able to hold each other tightly, and some water will spill on the table.

Experiment 3: Wooden Skewer Experiment With Soap

This one is almost the same as the pepper powder experiment. There is just one difference that instead of pepper powder, we will use wooden skewers.

• Wooden or bamboo skewers
• A large bowl
• Fill the bowl with water.
• Place three skewers in the shape of a triangle.
• Now ask your kid to add one or two drops of soap in the middle of the triangle.
• Observe the skewers’ movement.

You will observe that as soon as your child adds a few drops of soap to water, the triangle collapses. This is because the soap molecules broke the surface tension near the sticks, and the water molecules carried them towards the edges of the bowl.

The surface tension kept the sticks in their position but as soon as the surface tension was disturbed, water molecules started moving towards the edges carrying the cocktail sticks with them.

Final Words

Weren’t all these experiments exciting yet straightforward? I learned a lot about surface tension myself through these activities. I hope you will try them too and don’t forget to let me know how it went!

As a parent of a five-year-old inquisitive boy, I have gained a lot of experience finding fun activities and toys to help him understand science and understanding our world in general. On this blog, you’ll find an extensive amount of tutorials, guides, and toys about Science, Technology, Engineering, and Math based on my personal experience to help your child develop critical STEM skills.

Sharing is caring!

You May Also Like

Leave a Comment Cancel Reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

Day 7: Surface Tension

In kayak and canoe sprints, every movement must be precise.

Applying and releasing pressure at the right moments, timing the strokes just right, and perfectly maintaining your balance could be the difference between a gold-winning finish and not making the podium at all.

"The more you splash, the more you drag, the slower you're going to be," said Nevin Harrison , who won gold in the women's 200m canoe sprint in Tokyo, the first U.S. canoe sprint gold in 33 years and first-ever by a woman.

In kayak sprint races, riders sit front-facing in a narrow shell similar to that of a standard kayak. In canoe sprint, riders compete on one knee.

In the latest daily episode of The Podium: An NBC Olympic and Paralympic podcast, titled "Day 7: Surface Tension," Harrison, fellow U.S. teammates Aaron Small and Jonas Ecker , and Team USA coach Shelley Oates-Wilding describe all of the extreme technical elements of kayak and canoe sprints and just how critical it is to balance each piece.

"I feel like a lot of people ... think that because it's a pulling motion with your arm, it should [use] bicep," Harrison said. "But in reality, you want to keep your arm straight as long as you can and use your, back, your legs, your abs, all of those muscles to kind of get yourself going."

Hear all of that and more on the seventh daily episode of The Podium.

New episodes of The Podium will be released every day during the 2024 Paris Olympic Games. 

Follow the show on on the  iHeart App , Spotify , Apple Podcasts , Amazon Music or your favorite podcast.

Note: Some components of NBCOlympics.com may not be optimized for users browsing with Internet Explorer 11, 10 or older browsers or systems.

ON–OFF Control of Marangoni Self‑propulsion via A Supra‑amphiphile Fuel and Switch

• Zhu, Guiqiang
• Peng, Benwei
• Lin, Cuiling
• Zhang, Liqun
• Zhang, Qian
• Cheng, Mengjiao

Marangoni self‑propulsion refers to motion of liquid or solid driven by a surface tension gradient, and has applications in soft robots/devices, cargo delivery, self‑assembly etc. However, two problems remain to be addressed for motion control (e.g., ON–OFF) with conventional surfactants as Marangoni fuel: (1) limited motion lifetime due to saturated interfacial adsorption of surfactants; (2) in‑ situ motion stop is difficult once Marangoni flows are triggered. Instead of covalent surfactants, supra‑amphiphiles with hydrophilic and hydrophobic parts linked noncovalently, hold promise to solve these problems owing to its dynamic and reversible surface activity responsively. Here, we propose a new concept of 'supra‑amphiphile fuel and switch' based on the facile synthesis of disodium‑4‑azobenzene‑amino‑1,3‑benzenedisulfonate (DABS) linked by a Schiff base, which has amphiphilicity for self‑propulsion, hydrolyzes timely to avoid saturated adsorption, and provides pH‑responsive control over ON‑OFF motion. The self‑propulsion lifetime is extended by 50‑fold with DABS and motion control is achieved. The mechanism is revealed with coupled interface chemistry involving two competitive processes of interfacial adsorption and hydrolysis of DABS based on both experiments and simulation. The concept of 'supra‑amphiphile fuel and switch' provides an active solution to prolong and control Marangoni self‑propulsive devices for the advance of intelligent material systems.

Invest, Experiment, And Scale Back: Budget Priorities For CISOs In 2025

Jeff Pollard , VP, Principal Analyst

Security and risk (S&R) leaders today are under increasing pressure to prove the value of security investments due to increased budgets in recent years. Unlike other tech leaders, chief information security officers (CISOs) have largely avoided budget cuts, driven by a mix of regulatory pressures, customer expectations, and cyber insurance requirements. This has led to investment strategies aimed at bolstering security postures in the face of an evolving threat landscape but that has resulted in an increasingly complex computing environment due to technology sprawl.

The Current State Of Cybersecurity Spending Benchmarks

Over a third of security budgets are now allocated to software, surpassing both hardware and personnel expenses, which offers solid evidence of one of the CISO’s top challenges: technology bloat. The cybersecurity vendor ecosystem is characterized by a plethora of tools and technologies but a scarcity of skilled personnel to manage them effectively. Looking ahead, the majority of security technology decision-makers anticipate further budget increases in 2025, ranging from modest to significant, first to overcome the relentless pace of inflation and secondarily to deal with emerging security challenges. For security leaders, this will result in new tools, technologies, and vendors being introduced to an already crowded ecosystem of technologies. Our research serves as a guide to help leaders understand where others plan to spend, where they might take advantage of consolidation and innovation to make cuts, and where they should start experimenting to find new solutions that they plan to invest in for the future.

There are three key areas for CISOs to focus on in the year ahead as they plan for a future reshaped by technology disruption, adversary innovation, and economic tension:

• Making strategic investments to enhance security. For 2025, CISOs are encouraged to increase budgets in areas that impact revenue generation and help mitigate threats from ever-improving attackers. These areas include API security and software supply chain to protect revenue-generating applications, human risk management to protect the people that operate businesses, skills and training platforms to improve practitioners, and expanding the detection surface to include OT and IoT devices to establish complete visibility across an enterprise’s technology estate.
• Exploring emerging technologies. The dynamic nature of cyberthreats necessitates deploying emerging cybersecurity technologies, in some cases before enterprises thought they would need them. Areas ripe for experimentation in 2025 include exposure management and cyber risk quantification (which are slowly converging) to maximize visibility and contextual awareness, post-quantum security to protect their transactions and sensitive data, security data lakes to house the enormous amount of data that technologies generate, and AI and ML security to gain — and retain — competitive advantages in the marketplace.
• Divesting from outdated solutions. As cybersecurity evolves, certain once-critical solutions are failing to adapt well to the evolving threat landscape. Our Budget Planning Guide includes recommendations for divesting from these technologies and provides strategic and tactical guidance on which solutions will work as replacements. For late adopters, eliminating these technologies already may seem surprising, but it’s necessary when they no longer counter adversary tactics, techniques, and procedures.

Technologies included in the invest and experiment categories will keep CISOs aligned with broader business objectives in 2025 so that they don’t have to scramble and play catch-up as in years past. Those in the divest category no longer satisfy security use cases as they once did. Our 2025 Budget Planning Guide for S&R leaders will help you navigate through capacity constraints, budget challenges, and the need to build a robust and resilient security posture that satisfies the major constituencies CISOs must satisfy: customers and partners, cyber insurers, regulators, and shareholders.

To get more detail about these recommendations, download the full Budget Planning Guide 2025: Security And Risk report, and register for our upcoming webinar on September 24 to have your questions answered.

• Budget Planning Guides
• Cybersecurity Trends
• data security
• Endpoint Security
• IoT security
• network security
• security architecture
• Security management
• security risk management
• Security Services

Thanks for signing up.

Stay tuned for updates from the Forrester blogs.

Focus 2025 Security Budgets On Risk Mitigation And Tech Sprawl

Security leaders, explore our 2025 planning guide for benchmarks on where to invest, divest, and experiment with your budget., leverage synergy to stretch your 2025 b2b marketing budget, make the right tech budget decisions now to succeed with ai in 2025, get the insights at work newsletter, help us improve.