potato strips osmosis experiment

Make a Potato Shrink--with Saltwater

A water-moving science project from Science Buddies

By Science Buddies & Svenja Lohner

Create movement with salt! Learn how plant cells regulate water with an activity you can see--and feel.

George Retseck

Key Concepts Biology Osmosis Cells Chemistry Concentration Water transport

Introduction Have you ever wondered how plants "drink" water from the soil? Water uptake in plants is quite complicated. A process called osmosis helps the water move from the soil into the plant roots—and then into the plant's cells. In this activity you will see for yourself how you can make water move with osmosis!

Background Most water in the ground is not pure water. It usually contains dissolved mineral salts. Animals and plants need these salts (which include calcium, magnesium, potassium and the sodium you might be familiar with as table salt) to grow, develop and stay healthy. Different water sources carry different amounts of these salts. Nature wants to balance a system that is not balanced. So if you mix water with two different salt concentrations, the salts don't stay separated but spread out evenly through the solution until the salt concentration is the same throughout.

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.

You'll find a similar reaction if you separate two salt solutions with a semipermeable membrane. A semipermeable membrane is a type of barrier that only lets certain particles pass through while blocking others. This type of membrane usually lets water pass through but not the salts that are dissolved in the water. In this situation, because only water can move through this membrane, the water will start moving from the area of lower salt concentration (which has more water and less salt) to the area of higher salt concentration (which has less water and more salt). This water movement will only stop once the salt and water concentration on both sides of the membrane is the same.

The process of moving water across a semipermeable membrane is called osmosis. Plants use this process to their advantage for water uptake. They create an environment of high salt concentration in their root cells that are in contact with the soil. The cell walls act as a semipermeable membrane that only let water through. Because the water outside the root cells has a lower salt concentration, water starts moving into the root cells due to osmosis. The water entering the plant fills up the cells and can travel to the rest of the plant. Osmosis, however, works in both directions. If you put a plant into water with a salt concentration that is higher than the concentration inside its cells, water will move out of the plant to balance out the concentration difference. As a result the plant shrinks and eventually dies. You will see this effect with your own eyes in this activity using potatoes and different saltwater solutions.

Distilled water

Measuring cup with milliliters (mL)

Weight scale with gram measurements

Three plastic cups or glasses

At least three potatoes

Apple corer. (Alternatively, you can have an adult help you use a cutting board and knife.)

Knife (and an adult helper to help you use it)

Pen or pencil

Paper towels

Graphing paper (optional)

Other vegetable(s) or fruit (optional)

Preparation

Prepare three different saltwater solutions. Create labels for the three cups: "0 grams," "2 grams" and "4 grams."

To each of the cups add 100 mL of distilled water.

Weigh out 2 grams of table salt, and add it to the cup that says "2 grams." Then weigh out 4 grams of table salt, and add it to the cup labeled "4 grams." Use a spoon to mix the solutions until all the salt is dissolved.

Draw a table in which you can enter the starting measurements (length and diameter or width) and end measurements of each potato strip for every salt concentration (0, 2 and 4 grams).

Prepare at least three potato cores. Carefully push the corer all the way through the potato, and remove the core carefully so the potato piece stays intact. (Alternatively, you can have an adult help cut the potato into strips that all have the same dimensions.) The potato pieces should be at least one-half inch thick and two inches long. (Ideally you will be able to prepare nine matching cores or strips so you can test three pieces in each solution to compare the results thoroughly.)

Use a knife to carefully remove any potato skin from your cores, and rinse the cores quickly with water.

Use a ruler to ensure each potato piece is the same size (ideally to the millimeter). Carefully use a knife to trim any pieces as needed.

Measure the dimensions (length and diameter or width) of each potato strip in millimeters, and write the information in the table.

Optionally, you can also weigh each potato piece and record their weights.

Put one potato strip (or three if you made nine pieces) into each of the cups. While you do that feel the potato strips with your fingers and try to flex them a little bit. How do they feel? Are they easy to bend?

Start your timer for 30 minutes. Let the potato strips sit in the different solutions for the whole time. What do you think will happen to the strips in each of the cups?

After 30 minutes inspect the potato strips inside the solutions. Do you see any changes?

Take the potato strip(s) out of the "0 grams" cup and place on a paper towel. While doing that feel the potato pieces again and try to bend them slightly. How do they feel? Are they easier or more difficult to bend than before?

Use the ruler to measure the exact length and diameter or width (in millimeters) of each of the potato strips, and write the results in your table. What do you notice about the potato strip measurements? Optionally you can weigh these pieces and record their weights.

Next take the potato strips from the "2 grams" cup, and place them on a paper towel; as you do this feel them. Measure their lengths and diameters or widths. Write your results in the table. Optionally you can weigh these pieces and record their weights. What changed about these potato strips?

Repeat the same steps with the potato strips in the "4 grams" cup. Write your results in the table. Are your results for these similar or different compared with the other ones?

How did the feeling of the strips compare based on what solution they were in? Why do you think this is?

Compare the results in your table. How did the length and diameter or width of the potato strips change in each cup? What about the weights if you took them? Can you explain your results?

Extra: If you weighed each of your strips before and after soaking them, compare the weights. How does the mass of the potato strips change in each solution?

Extra: Leave the potato strips in the solutions for a longer time period. How do they look if you let them soak in the saltwater for one hour or overnight?

Extra : If you have graphing paper, make a graph of your results with the salt concentration on the horizontal axis and the potato strip length or diameter after soaking on the vertical axis. Draw two lines to make your graph. For the first, connect each of the data points you found. For the second, draw a horizontal line starting at the point on the vertical axis that shows the original length of your potato strip. Based on your graph can you find a salt concentration at which the potato strip length should not change at all?

Extra: How does the activity work with other vegetables or fruit? Try it to find out!

Observations and Results Did your potato strips shrink and expand? At the beginning all the potato strips should have had the same length and should have all felt the same. When you put them into the different solutions, however, this starts to change. Whereas the potato strips in the "0 gram" cup probably got larger in size, the other potato strips probably got shorter after leaving them in the saltwater for 30 minutes. (If you didn't see any significant changes after 30 minutes, leave the potato strips in the saltwater solutions longer.)

The shrinking and expanding of the potato strips is due to osmosis. Potatoes are made of cells, and their cell walls act as semipermeable membranes. The 0 grams solution contains less salts and more water than the potato cells (which have more salts and less water). To balance out these concentration differences, the water from the cup moves into the potato cells. The incoming water in the potato cells pushes on the cell walls and makes the cells bigger. As a result the whole potato strip gets bigger. The opposite is the case in the higher concentration salt solutions. If the salt concentration in the cup is higher than inside the potato cells, water moves out of the potato into the cup. This leads to shrinkage of the potato cells, which explains why the potato strips get smaller in length and diameter. Due to the shrinking of the potato cells the potato strip also becomes less rigid. If you bent the potato strips, you should have noticed that those that had been in the solution with the highest amount of salt were much easier to bend than the potato strips in the water without salt.

If you made the graph you probably noticed that there is a salt concentration at which the potato strip neither expands nor shrinks. This should be where your data curve and your start length line intersect. At this point the salt concentration inside the potato cells and inside the cup are the same. Because the concentrations are already balanced no water moves.

Cleanup Discard the saltwater solutions in the sink. Throw the potato strips into the compost, and clean up your workspace. You can cook with the other pieces of unused potato.

More to Explore Osmosis , from Biology Dictionary Do Fish Drink? from McGill University's Office for Science and Society Cucumber Chemistry: Moisture Capture with Desiccants , from Scientific American Suck It Up! How Water Moves Through Plants , from Science Buddies STEM Activities for Kids , from Science Buddies

• Biology Article
• Study Of Osmosis By Potato Osmometer

Understanding Osmosis Using Potato Osmometer

To study by demonstrating the osmosis process by potato osmometer.

What is Osmosis?

Osmosis is the phenomena in which solvent molecules pass through a semi-permeable membrane from an area of higher concentration to an area of lower concentration. The process continues until the quantity of fluid is balanced or equalized in both regions, the region of higher concentration and the region of lower concentration of the semipermeable membrane. In other words, osmosis is the diffusion or movement of water from a region of higher water potential to a region of lower water potential.

In osmosis, what are solvent and solute?

The fluid that permeates through the semipermeable membrane is called the solvent, whereas the solute is the dissolved particles in the fluid.

What is the solution?

The mixture of solute and solvent form the solution.

List the different types of solutions.

The following are the types of solutions:

• Hypertonic solution – It is a solution with a high solute level. If living cells are placed in a hypertonic solution, because of lower concentration water moves out of the cell causing it to shrink and becomes plasmolyzed.
• Hypotonic solution – It is a solution with low concentration levels of solute. If living cells are placed in this solution, water passes into the cells because of higher water concentration in comparison to the cell causing the cells to swell and turn turgid.
• Isotonic solution – A solution is said to be isotonic if both solutions have an equal concentration of solute. If living cells are placed in an isotonic solution, no change is shown as there is the equal concentration on both the regions hence the cell retains its original shape.

Material Required

• A fresh large-sized potato tuber
• 20% sucrose solution
• Scalpel/blade
• A Bell pin needle that is labelled with a waterproof ink

• Slice the potato tuber into two equal halves with the help of a scalpel or a blade. The outer skin is to be peeled off. Since the tuber shape is irregular, slice the halves into squares
• From the mid-region of the tuber, scoop from the soft parenchyma, so as to form a tiny cavity of a square or a circular shape. At the base, the cavity prepared should have a minimum thickness.
• Fill up half the cavity with the freshly prepared 20% sugar solution. Into the cavity, fix a pin in a way that the mark is in the same line with the layer of the sucrose solution.
• Set up the osmometer in a Petri dish/beaker that is filled with water in a way such that 75% of the potato osmometer is immersed in water
• The set up should remain uninterrupted for close to 1 hour.
• Notice the sugar solution in the osmometer towards the end of the experiment
• Carry out the experiment with the help of water in the cavity and the sucrose solution in the petri dish/beaker.

Observation

After a period of time, within the osmoscope, the sugar solution rises and is seen coloured.

• An increase in the level of sucrose solution is observed in the osmometer. It is because of the entrance of water due to endosmosis from the beaker.
• Also, a water potential gradient is built between the sucrose solution in the external water and the osmometer.
• Though both the liquids are divided by living cells of the potato tuber, they allow the entrance of water into the sugar solution.
• This demonstrates the entrance of water into the sugar solution through the tissues of potato serving as a selectively permeable membrane.

Viva Questions

Q.1. What is plasmolysis?

A.1. It is a process, wherein the protoplasm of the plant cell turns round as a result of contraction when placed in a hypertonic solution due to exosmosis resulting in the decline in the tension of the cell wall.

Q.2. What is the significance of osmosis?

A.2. Osmosis maintains cell turgidity. It causes the transportation of nutrients and discharge of metabolic waste products. It preserves the interior environment of a living entity to maintain an equilibrium between the intracellular fluid levels and water.

Q.3. What is diffusion?

A.3. The movement of molecules from a region of higher concentration to a region of lower concentration. Osmosis is a type of diffusion.

For more information on related biological concepts and experiments, please register at BYJU’S.

Related Links:

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 Biology 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

Good Thank you BYJU’S!!

Register with BYJU'S & Download Free PDFs

Register with byju's & watch live videos.

Search for:

Your cart is currently empty!

Potato Osmosis Experiment

Osmosis is the movement of water from an area of its lower concentration to its higher concentration across a semi-permeable cell membrane. The addition of salt can change the concentration of water and the osmotic gradient. Salt can help us cook. In this osmosis experiment you will see how salt affects potato sticks.

WHAT YOU NEED

What you will do.

Ask an adult to help you cut the potato into even, rectangular sticks.

Do not consume any of the materials used in the experiment!

RECORD YOUR OBSERVATIONS AFTER 6-8 HOURS

CONCLUSIONS

What happened to the potato in the salt water? Why? Which way was the water moving?

What happened to the potato in the regular water? Why? Which way was the water moving?

Copyright @smorescience . All rights reserved. Do not copy, cite, publish, or distribute this content without permission.

SUBSCRIBE TO OUR NEWSLETTER

Subscribe to our mailing list to get updates to your email inbox..

Monthly Newsletter

Related Posts

Gay penguin “power couple” raised two chicks. now, one of them has died.

First Private Trip To Space, And Now The First Private Spacewalk— What’s Next For Billionaire Jared Isaacman And Polaris Program

A New Way to Learn Math

South American Lungfish Sets New Record In Animal Genome Size: Here’s Why They Are Odd

• Privacy Policy
• Science Kits
• Affiliate Login

Osmosis Potato Experiment: DIY Science Project Ideas for Kids

Finished with your lesson on Osmosis but still confused? Then you need to perform this simple Osmosis experiment. All you need are some potato slices and water. Learn about osmosis with potato slices in this simple osmosis potato experiment. Performing science experiments for kids will enable them to understand challenging scientific concept they are learning in a much better way.

Step-by-Step Instructions on How to Perform Osmosis Potato Experiment

Osmosis is the process by which water or any other solvent moves towards a solution with a higher concentration through a semipermeable membrane. The molecules in the solution with a lower concentration move towards the solution with a higher concentration to equalize the concentration on both sides. Osmosis is how plants absorb water and nutrients from the soil.

A simple science experiment for kids like the Osmosis Potato Experiment helps kids understand the concept easily.

What You’ll Need?

If you leave cut slices of potatoes or apples or pears outside for a while, you’ll notice that they turn brown. Why do you think this discoloration occurs? When you cut these fruits or vegetables, it leaves the cells open. An enzyme present in the cells, polyphenol oxidase, reacts with the oxygen in the air and turns the fruit brown. But can you prevent the slices from turning brown and keep them fresher for longer? Let’s learn through this osmosis potato experiment.

Here is a list of things you’ll need to perform the experiment:

• 1 medium sized potato
• 2 – 4 tablespoons of salt
• Distilled water
• 2 medium sized mason jars or drinking glasses

How to Perform Osmosis Potato Experiment?

Follow these instructions to perform the experiment:

• Step 1: Peel and cut the potatoes so you have wedges that are neither too thick nor too thin. Ensure that the potato wedges are roughly the same size. Note down the color of the freshly cut potato wedges and how they feel when you touch them.
• Step 2: Pour 200ml of distilled water into one glass or jar. 
• Step 3: Into the second glass, pour 200ml of distilled water and add 2-4 tablespoons of salt. Stir it well until the salt is completely dissolved.
• Step 4: Add two potato wedges into each of the glasses and let them sit overnight.
• Step 5: The next day, you’ll notice a difference in both the glasses. The potato wedges in the glass with the unsalted water have become bigger, while the wedges in the salted water have shrunk slightly.
• Step 6: Take the potato wedges out of the unsalted water and try bending them. You’ll notice that it is firm and breaks but doesn’t bend. Additionally, it still has a white color like a freshly cut piece of potato.
• Step 7: Now take the potato wedges out of the salted solution and try to bend them. You’ll notice the wedges have turned brown and bend easily without breaking.

What You’ll See?

Once you’ve performed the experiment, help your child understand the science behind the osmosis experiment. Here are a few questions and answers that will help children understand the behavior of the potato wedges in the two different solutions.

• Why did the potato wedges in the glass with plain distilled water become bigger?

The potato wedges expand and become bigger because of osmosis. Potatoes are made of millions of cells and the cell walls act as a semipermeable membrane. The water molecules move into the potato through this membrane to balance the concentration levels. The water moving inside the potato cells causes it to expand and become bigger. 

• Why did the potato wedges in the glass with salt water shrink?

Again it’s because of osmosis. The salt solution has a higher concentration and the water inside the potato moves through the cell walls to balance the concentration in the saltwater. Since the water moves out of the potato wedge, it shrinks and becomes smaller. This is also the reason why the potato wedge in the salt solution becomes less rigid and bends easily.

• Why did the potato wedges in the salt solution change color?

The water moving out of the potato damages it’s cells, which causes them to release an enzyme called catechol oxidase. The enzyme in the potato cells reacts with the oxygen in the air and turns the wedges brown.

Other Way to Perform Osmosis Potato Experiment for Kids

Another cool way to see osmosis in action is to perform this experiment using grapes and raisins.

• 2 – 3 raisins
• 2 – 3 fresh grapes
• 3 – 4 tablespoons of sugar

Step-by-Step Guide on How to Perform Osmosis Potato Experiment

Follow these instructions to perform this experiment:

• Step 1: Add the 3 – 4 tablespoons of sugar into one glass of water and stir it until all the sugar is dissolved. Then add 2 -3 fresh grapes into the sugar solution.
• Step 2: Add 2 – 3 raisins to the second glass of water. Allow both glasses to sit for a few hours.
• Step 3: After a few hours, you’ll notice that the raisins in the plain water have plumped up almost as if they are grapes. The raisins have a higher concentration of sugar, so the water moves into the raisins to balance the amount of sugar. This causes the raisins to expand and plump up.
• Step 4: Meanwhile the grapes in the sugar solution have shrunk and almost look like raisins. The water surrounding the grapes has a higher concentration of sugar than water in the grape cells. So the water in the grape cells moves out to balance the level of sugar. This causes the grapes to shrink in size.

Can you use other vegetables or fruits to perform this experiment? Will sliced bananas or pineapples work the same way? The only way to know is to try. Looking for more cool science experiments to try with your kids? Check our kids learning section for more fun and informative science experiments.

Frequently Asked Questions on Osmosis Potato Experiment

What is osmosis.

Osmosis is the process by which a solution with a lower concentration moves towards a solution with a higher concentration through a semipermeable membrane to balance the levels of concentration.

Why does the potato in the salt solution shrink?

Potato cells also have water in them. The water in the potato tries to equalize the concentration by moving towards the saltwater. The loss of water causes the potato to shrink and also makes it bendy and less firm.

Subscribe to Osmo & get

your first purchase

You’ve been subscribed with

Check the welcome mail to download the printables and avail your discount.

Explore our award-winning products for kids learning.

* Offer valid only for 7 days.

Study of Osmosis by Potato Osmometer

A study of osmosis can be done using a potato osmometer. Osmosis is a phenomenon in which water moves from high solvent to low solvent concentration. The movement of water occurs between two compartments, separated by a semipermeable membrane .

The cell membrane of living organisms behaves as a semipermeable or selective membrane. The permeability of a selective membrane differs based on the size, charge and mass of different molecules.

Biological membranes are impermeable to large biomolecules and polar molecules like ions. But, non-polar molecules (lipids) and small molecules (oxygen, carbon dioxide etc.) can cross the selective barrier.

Water is the solvent that travels down or up the cell concentration gradient through osmosis. We can study water diffusion by creating two compartments and a semipermeable membrane in between.

The difference in the concentration of solutes or solvents between two compartments is the driving force responsible for water movement. Here, we need to note that only solvents can pass the selective barrier, not solutes.

Thus, the diffusion or distribution of water is related to osmosis . This post describes the meaning, requirements, procedure and results of the potato osmometer experiment.

Content: Study of Osmosis by Potato Osmometer

Potato osmometer, materials required, precautions.

It is a common experiment to demonstrate both endosmosis and exosmosis using a potato. Using a potato Osmoscope, we can study osmosis in a living system.

Here, a potato is used because the porous outer surface of the potato acts as a selective membrane .

• The contents within the cell form one compartment.
• The solution surrounding the cell forms another compartment.

Thus, a selective membrane separates two compartments and allows the process of osmosis .

• High solvent concentration in the cell surrounding.
• Low solvent concentration in the cavity of potato tuber.

Following the rule of osmosis, water in the cell surrounding enters the tuber cavity via the cell membrane.

• High solvent concentration in the cavity of potato tuber.
• Low solvent concentration in the cell surrounding.

Following the rule of osmosis, water in the potato cavity enters the surrounding solution via the cell membrane.

• Peeled off potato
• Concentrated sugar solution
• Petri plate

Video: Study of Osmosis

To perform the potato osmometer experiment, we need to follow the given procedure:

• First, peel off the large-sized potato using a peeler or knife.
• Then cut the upper and lower portions of the peeled potato using a knife. Through this step, we can easily place the potato on the Petri plate.
• Using a knife, make a cavity from the centre of the potato deep into the bottom, leaving some space. Here, the bottom of the potato will function as a selective membrane.
• Then, keep the potato on the Petri plate.
• To study endosmosis , pour water into half of the Petri plate. Next, pour the concentrated sugar solution into half of the cavity created in the potato.
• To study exosmosis , add concentrated sugar solution on the Petri plate and water into the cavity of the potato tuber.
• Then, fix a pin into the potato tuber-A and B to mark the level of sugar solution and water added into the cavity.
• Leave the plate undisturbed for some time until you notice any change.

Observation

• Observe the level of sugar solution in the cavity of potato tuber-A.
• Notice the level of water in the cavity of the potato tuber-B.

Potato Osmosis Experiment Results

• The level of sugar solution in the cavity of potato tuber-A increases . It occurs because the water in the Petri plate will move towards the cell with a high solute or low solvent concentration. This experiment shows endosmosis , as water goes into the cell or potato tuber.
• In contrast, the level of water in the cavity of potato tuber-B decreases . Here, water in the cavity moves toward the solution in the Petri plate due to the high solute concentration in the surrounding. This experiment shows exosmosis as water leaves the cell or potato tuber.
• The cavity should be deep enough by leaving a minimum thickness at the bottom.
• The sugar solution should have a high osmotic concentration.

The water movement from the Petri plate to the potato cavity or vice versa is due to the difference in the solvent or solute concentration between the two compartments.

Related Topics:

• Germination of Plant
• Difference Between Root and Stem
• Nerve Impulse
• Ozone Formation
• Examples of Adsorption in Daily Life

Leave a Comment Cancel Reply

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

Start typing and press enter to search

Potato Osmosis

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 ⋅

Science Experiments on the Osmosis of a Potato

Osmosis Experiments With Potatoes for Kids

Osmosis, the process in which solvent molecules move from an area of lower solute concentration to an area of higher solute concentration, can easily be demonstrated with potato experiments. Potatoes are full of both water and starch, and will gain water when immersed in watery solutions. Conversely, they will lose water when in concentrated solutions, such as those containing a great deal of starch. You can use potatoes to set up osmosis experiments for students of all ages and levels.

Potatoes in Saltwater

Cut a potato in two, and immerse one of the halves in a very salty solution of water — one containing a quarter cup of salt in a cup of water. Immerse the other piece in tap water containing no added salt. Leave both in their respective solutions for half an hour, then remove the potato halves from their solutions and observe their differences. The one in the salty solution will have shrunk, indicating that water is diffusing from a less concentrated solution to a more concentrated solution. The one in the tap water solution, in contrast, will actually swell slightly, indicating that it is taking in water.

Salt, Sugar and Pure Water

This experiment helps students to differentiate between different degrees of concentration gradients. Make one salt water solution, one sugar water solution, and for the third solution, simply use tap water. Make three thin potato slices — 1/2 cm thick. Place each potato slice into each of the solutions, and leave the slices in the solutions for a half hour.

Observe that the slice placed in salt is very flexible, while the slice placed in sugar is flexible, but less so. Since potatoes already contain sugar, less water will diffuse out of the potato placed in sugar water. The slice placed in water will be rigid, since it will absorb water.

Potato Lengths in Saline Solutions

Give your students potato "cylinders" that are uniform in length and size: for instance, you could cut them to be 70 mm in length and 7 mm in diameter. Make solutions of saline in three different concentrations, 20 percent, 0.9 percent and 0.1 percent. Have the students measure the lengths and diameters of the potato cylinders before and after soaking them in the saline solutions for half an hour. Then, have them calculate the changes in the lengths and diameters of the cylinders, and plot the saline concentrations versus the changes.

Potato Cube Weights

Cut potatoes into four groups of small, uniform cubes measuring 1/2 cm by 1/2 cm. Make four different solutions of sucrose: 10 percent, 5 percent, 1 percent and 0.01 percent. Weigh each group, on a mass balance, before immersing it in the appropriate sucrose solution for half an hour. After immersion, weigh each group again and have your students calculate the changes in the potato masses. Ask them to comment on why a group gained mass, lost mass or retained the same mass.

Related Articles

Osmosis science activities for kids, ib group 4 project ideas, fun science experiments with potatoes, science projects for cut flowers, high school science experiments with plants, sugar & salt crystal science projects, how to grow a potato in water for a science project, ideas for a science fair project using kool-aid, science fair on how vitamin c & ibuprofen affect plant..., how to measure solubility for a science project, activities on conductivity, water evaporation science fair projects, how to make a five percent solution with salt, how to make crystals out of salt, science projects and research with salt, sugar, water..., polarity projects using a potato, how to make polymer crystals, osmosis egg experiments, how to make a saltwater battery for a science project.

• The Teachers Corner: Science Experiment--Osmosis

About the Author

Tricia Lobo has been writing since 2006. Her biomedical engineering research, "Biocompatible and pH sensitive PLGA encapsulated MnO nanocrystals for molecular and cellular MRI," was accepted in 2010 for publication in the journal "Nanoletters." Lobo earned her Bachelor of Science in biomedical engineering, with distinction, from Yale in 2010.

Find Your Next Great Science Fair Project! GO

• No category

Biology – Potatoes Osmosis Lab Report

Related documents.

Study collections

• education if my future

Add this document to collection(s)

You can add this document to your study collection(s)

Add this document to saved

You can add this document to your saved list

Suggest us how to improve StudyLib

(For complaints, use another form )

Input it if you want to receive answer