yeast sugar water experiment

Yeast and Sugar Science Fair Project

40 Comments

In this Yeast and Sugar Science Fair Project, we’ll watch yeast feed on sugar to fill a balloon with air. A fun science project for kids that’s with household, everyday materials.

Our Inspiration

I’ve been baking bread just about every day for the past three weeks (nothing too crazy since it’s all done in the bread maker), but last week my 3.5 year old and I got into a discussion about the properties of yeast.

We like to tinker and  experiment — big surprise, I know — and decided to see what would happen if we mixed yeast with warm water.

My preschooler took this job very seriously, poured the water into a bowl, added a couple teaspoons of yeast, and waited a few patient minutes before she said, “it makes a brownish color.” True, and to make it bubble like it does in bread, we needed to activate it with sugar.

What’s so great about an experiment like this is that it’s easy to do with household materials, and it’s ripe for authentic child-generated questions and observations. When I asked what she thought would happen if we added sugar to the yeast she said, “I don’t know! Let’s mix them and find out!.”

Supplies: Yeast and Sugar Science Fair Project

• Sugar, 2 tablespoons
• Active Dry Yeast, 1 packet or 2 1/4 tablespoons
• Warm water (105-115 degrees F, 40.5-46 degrees C)
• Mixing bowl + funnel
• Bottle that you can fit a balloon over

Mix the yeast and sugar into the warm water and stir. I noticed that N was sniffing the concoction and asked her what it smelled like. She said “poop.” I could see what she was saying. Consider yourself warned.

Once it all dissolves, pour the mixture into the bottle and cover the bottle with the balloon.

After a few minutes you’ll be amazed by something like this!

Will it blow off the bottle?

N wanted to feel it as it filled with air. She noticed the balloon was getting bigger and wanted to know how big it would get, wondering out loud, “will it fill up all the way and blow off the bottle?”

Good question!

My handy-dandy ship captain sister (no joke — that’s her job!) was visiting, and put herself right to work as chief measurer.

Move it to a safe spot

Once the bottle filled up completely, we moved the whole yeast sugar experriment to the sink. The bubbles were slow-moving, and there was nothing to worry ourselves with, but N enjoyed pulling the balloon off and watching the foam slowly pour over the bottle’s top.

Ideas for Extending this Experiment

As we went through the process, I thought of a few fun extensions for older kids or those who want to take this further. You could play around with food coloring/liquid watercolors, have a few bottles going at once and compare the results of different sugar:yeast ratios, or compare the results of different water temperatures.

I found my recipe at The Exploratorium’s Science of Cooking series, where we also learned that as the yeast eats the sugar it makes carbon dioxide, which is essentially the same process that yeast goes through in our bread dough.

Mmmmm. I’m off to eat some whole wheat cranberry walnut oat bread. Toasted. With butter and Maldon salt. How do you like your bread? And have you played around with yeast concoctions?

More Science Experiments for Kids

If you enjoyed this project, you’ll love this article:  Science Fair Project Ideas .

What a great idea!!

Thanks, Deborah 🙂

thank you soooooooooooooooooooooooooooo much for this info

I used to bake a lot of bread with my boys when they were younger (pre-celiac diagnosis) and they always loved my scientific explanation of why the bread rises: the yeast eats the sugar and farts. 🙂 That’s what all the bubbles are, of course!

Yep, farts would be another not-so-pretty way to describe this process. Between that and my daughter’s description, I’m not sure if anyone will want to try this themselves 😉

we love yeast! my son thinks of yeast as little pets. here is our experiment we did a few months ago. it seems to come up ever year or so. great post!

http://mamascouts.blogspot.com/2011/09/science-experimentwake-up-yeast.html

Thanks for sharing your yeast experiments, Amy! I love them, and we have to try this with maple syrup next time (if I can convince my MS-adoring family to part with it first!).

way cool! you know I like to tinker as well with my girls – this will be something we can easily do at home.

I pinned this! 🙂 thanks for sharing!

Thanks for pinning it, Bern 🙂 And yes, I can totally imagine your two little scientists going crazy over this one!

This is the best blog for experiments! Thanks for sharing all your great ideas.  Linking up to it in a science for preschoolers post. 

Hi Kristin, Thank you soooooo much for the kind words about Tinkerlab. And thanks for sharing us with your readers….feel free to send me a link if you’d like and I’ll share it on Facebook.

This is so fun! We did this today and the kids loved it. Thank you!

awesome, lindsie! i’m thrilled to hear it was successful. thanks for taking time to give me this update.

Hmmm…sugar, yeast and water…also known as Kilju or sugar wine! https://en.wikipedia.org/wiki/Kilju

As well as CO2, yeast and sugar also produces Ethanol (alcohol). Probably best not to teach the kids that part though!

That’s funny, Chris. I’m sure that my 4-year old won’t be least bit interested in sugar wine!

Point taken. Out of interest, did you ever find out what made the “poop” smell? In theory it should just produce CO2 which doesn’t smell.

could i add flour to the mixture. would it have the same effect ?

it’s nice

moooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo

why soooooooo many o’s sara

What quantity of water did you use? I’m doing an adaptation of this for my science assignment

Miguel Cabrera

What were the measurements for each balloon

Thanks for this great post. We did this today while baking bread. My boys loved measuring the baloons often and seeing what would happen.

[…] is a safe activity for preschoolers and toddlers because you are using edible materials. Moreover, kids will see, touch, and smell while observing, […]

Thanks Nice Experiment

I don’t get it, it does not have a video!

[…] Blow Balloon With Yeast Experiment […]

Is this supposed to be 2 1/4 TEASPOONS or TABLESPOONS. Your instructions say one packet of yeast (which is 2/4 teaspoons) but you wrote 2 1/4 tablespoons. Thanks for any clarification you can provide

* my comment should read that one packet of yeast is 2 1/4 teaspoons

Comments are closed.

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The fermentation of sugars using yeast: A discovery experiment

Charles Pepin (student) and Charles Marzzacco (retired), Melbourne, FL

Introduction

Enzyme catalysis 1  is an important topic which is often neglected in introductory chemistry courses. In this paper, we present a simple experiment involving the yeast-catalyzed fermentation of sugars. The experiment is easy to carry out, does not require expensive equipment and is suitable for introductory chemistry courses.

The sugars used in this study are sucrose and lactose (disaccharides), and glucose, fructose and galactose (monosaccharides). Lactose, glucose and fructose were obtained from a health food store and the galactose from Carolina Science Supply Company. The sucrose was obtained at the grocery store as white sugar. The question that we wanted to answer was “Do all sugars undergo yeast fermentation at the same rate?”

Sugar fermentation results in the production of ethanol and carbon dioxide. In the case of sucrose, the fermentation reaction is:

\[C_{12}H_{22}O_{11}(aq)+H_2 O\overset{Yeast\:Enzymes}{\longrightarrow}4C_{2}H_{5}OH(aq) + 4CO_{2}(g)\]

Lactose is also C 12 H 22 O 11  but the atoms are arranged differently. Before the disaccharides sucrose and lactose can undergo fermentation, they have to be broken down into monosaccharides by the hydrolysis reaction shown below:

\[C_{12}H_{22}O_{11} + H_{2}O \longrightarrow 2C_{6}H_{12}O_{6}\]

The hydrolysis of sucrose results in the formation of glucose and fructose, while lactose produces glucose and galactose.

sucrose + water \(\longrightarrow\) glucose + fructose

lactose + water \(\longrightarrow\) glucose + galactose

The enzymes sucrase and lactase are capable of catalyzing the hydrolysis of sucrose and lactose, respectively.

The monosaccharides glucose, fructose and galactose all have the molecular formula C 6 H 12 O 6  and ferment as follows:

\[C_{6}H_{12}O_{6}(aq)\overset{Yeast Enzymes}{\longrightarrow}2C_{2}H_{5}OH(aq) + 2CO_{2}(g)\]

In our experiments 20.0 g of the sugar was dissolved in 100 mL of tap water. Next 7.0 g of Red Star ®  Quick-Rise Yeast was added to the solution and the mixture was microwaved for 15 seconds at full power in order to fully activate the yeast. (The microwave power is 1.65 kW.) This resulted in a temperature of about 110  o F (43  o C) which is in the recommended temperature range for activation. The cap was loosened to allow the carbon dioxide to escape. The mass of the reaction mixture was measured as a function of time. The reaction mixture was kept at ambient temperature, and no attempt at temperature control was used. Each package of Red Star Quick-Rise Yeast has a mass of 7.0 g so this amount was selected for convenience. Other brands of baker’s yeast could have been used.

This method of studying chemical reactions has been reported by Lugemwa and Duffy et al. 2,3  We used a balance good to 0.1 g to do the measurements. Although fermentation is an anaerobic process, it is not necessary to exclude oxygen to do these experiments. Lactose and galactose dissolve slowly. Mild heat using a microwave greatly speeds up the process. When using these sugars, allow the sugar solutions to cool to room temperature before adding the yeast and microwaving for an additional 15 seconds.

Fermentation rate of sucrose, lactose alone, and lactose with lactase

Fig. 1 shows plots of mass loss vs time for sucrose, lactose alone and lactose with a dietary supplement lactase tablet added 1.5 hours before starting the experiment. All samples had 20.0 g of the respective sugar and 7.0 g of Red Star Quick-Rise Yeast. Initially the mass loss was recorded every 30 minutes. We continued taking readings until the mass leveled off which was about 600 minutes. If one wanted to speed up the reaction, a larger amount of yeast could be used. The results show that while sucrose readily undergoes mass loss and thus fermentation, lactose does not. Clearly the enzymes in the yeast are unable to cause the lactose to ferment. However, when lactase is present significant fermentation occurs. Lactase causes lactose to split into glucose and galactose. A comparison of the sucrose fermentation curve with the lactose containing lactase curve shows that initially they both ferment at the same rate.

Fig. 1. Comparison of the mass of CO 2 released vs time for the fermentation of sucrose, lactose alone, and lactose with a lactase tablet. Each 20.0 g sample was dissolved in 100 mL of tap water and then 7.0 g of Red Star Quick-Rise Yeast was added.

However, when the reactions go to completion, the lactose, lactase and yeast mixture gives off only about half as much CO 2  as the sucrose and yeast mixture. This suggests that one of the two sugars that result when lactose undergoes hydrolysis does not undergo yeast fermentation. In order to verify this, we compared the rates of fermentation of glucose and galactose using yeast and found that in the presence of yeast glucose readily undergoes fermentation while no fermentation occurs in galactose.

Fig. 2. Comparison of the mass of CO 2 released vs time for the fermentation of sucrose, glucose and fructose. Each 20 g sugar sample was dissolved in 100 mL of water and then 7.0 g of yeast was added.

Fermentation rate of sucrose, glucose and fructose

Next we decided to compare the rate of fermentation of sucrose with that glucose and fructose, the two compounds that make up sucrose. We hypothesized that the disaccharide would ferment more slowly because it would first have to undergo hydrolysis. In fact, though, Fig. 2 shows that the three sugars give off CO 2  at about the same rate. Our hypothesis was wrong. Although there is some divergence of the three curves at longer times, the sucrose curve is always as high as or higher than the glucose and fructose curves. The observation that the total amount of CO 2  released at the end is not the same for the three sugars may be due to the purity of the fructose and glucose samples not being as high as that of the sucrose.

Fermentation rate and sugar concentration

Next, we decided to investigate how the rate of fermentation depends on the concentration of the sugar. Fig. 3 shows the yeast fermentation curves for 10.0 g and 20.0 g of glucose. It can be seen that the initial rate of CO 2  mass loss is the same for the 10.0 and 20.0 g samples. Of course the total amount of CO 2  given off by the 20.0 g sample is twice as much as that for the 10.0 g sample as is expected. Later, we repeated this experiment using sucrose in place of glucose and obtained the same result.

Fig. 3. Comparison of the mass of CO 2  released vs time for the fermentation of 20.0 g of glucose and 10.0 g of glucose. Each sugar sample was dissolved in 100 mL of water and then 7.0 g of yeast was added.

Fermentation rate and yeast concentration

After seeing that the rate of yeast fermentation does not depend on the concentration of sugar under the conditions of our experiments, we decided to see if it depends on the concentration of the yeast. We took two 20.0 g samples of glucose and added 7.0 g of yeast to one and 3.5 g to the other. The results are shown in Fig. 4. It can clearly be seen that the rate of CO 2  release does depend on the concentration of the yeast. The slope of the sample with 7.0 g of yeast is about twice as large as that with 3.5 g of yeast. We repeated the experiment with sucrose and fructose in place of glucose and obtained similar results.

Fig. 4. Comparison of the mass of CO 2 released vs time for the fermentation of two 20.0 g samples of glucose dissolved in 100 mL of water. One had 7.0 g of yeast and the other had 3.5 g of yeast.

In hindsight, the observation that the rate of fermentation is dependent on the concentration of yeast but independent of the concentration of sugar is not surprising. Enzyme saturation can be explained to students in very simple terms. A molecule such as glucose is rather small compared to a typical enzyme. Enzymes are proteins with large molar masses that are typically greater than 100,000 g/mol. 1  Clearly, there are many more glucose molecules in the reaction mixture than enzyme molecules. The large molecular ratio of sugar to enzyme clearly means that every enzyme site is occupied by a sugar molecule. Thus, doubling or halving the sugar concentration cannot make a significant difference in the initial rate of the reaction. On the other hand, doubling the concentration of the enzyme should double the rate of reaction since you are doubling the number of enzyme sites.

The experiments described here are easy to perform and require only a balance good to 0.1 g and a timer. The results of these experiments can be discussed at various levels of sophistication and are consistent with enzyme kinetics as described by the Michaelis-Menten model. 1  The experiments can be extended to look at the effect of temperature on the rate of reaction. For enzyme reactions such as this, the reaction does not take place if the temperature is too high because the enzymes get denatured. The effect of pH and salt concentration can also be investigated.

• Jeremy M. Berg, John L. Tymoczko and Lubert Stryer,  Biochemistry , 6th edition, W.H. Freeman and Company, 2007, pages 205-237.
• Fugentius Lugemwa, Decomposition of Hydrogen Peroxide,  Chemical Educator , April 2013, pages 85-87.
• Daniel Q. Duffy, Stephanie A. Shaw, William D. Bare, Kenneth A. Goldsby, More Chemistry in a Soda Bottle, A Conservation of Mass Activity,  Journal of Chemical Education , August 1995, pages 734-736.
• Jessica L Epstein, Matthew Vieira, Binod Aryal, Nicolas Vera and Melissa Solis, Developing Biofuel in the Teaching Laboratory: Ethanol from Various Sources,  Journal of Chemical Education , April 2010, pages 708–710.

More about April 2015

Department of Chemistry 200 University Ave. W Waterloo, Ontario, Canada N2L 3G1

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Fermentation of glucose using yeast

• Four out of five

Carry out this practical and use the follow-up questions to explore an important fermentation reaction

Add some fresh context to this classic experiment with  Is fermented food and drink good for us?  in  Education in Chemistry . The article tucks into the science of fermentation and its everyday applications, from kombucha to kefir, and puts the supposed health benefits under the microscope. 

Beer and wine are produced by fermenting glucose with yeast. Yeast contains enzymes that catalyse the breakdown of glucose to ethanol and carbon dioxide. In this experiment, learners will set up a glucose solution to ferment and then test the products. You may also demonstrate distilling the fermentation mixture to separate the ethanol formed or set this as a learner activity. 

Download this

Carry out the fermentation of glucose using yeast with 14–16 learners. Observe and test the products, follow up with questions to consolidate learning and/or the distillation of ethanol.

The experiment is part of the  Nuffield practical collection , developed by the Nuffield Foundation and the Royal Society of Chemistry. Delve into a wide range of chemical concepts and processes with this collection of over 200 step-by-step practicals.

Learning objectives

• Carry out and observe a fermentation reaction.
• Test the products of a fermentation reaction.
• Explain the conditions needed for a fermentation reaction.

The experiment allows learners to cover the first two learning objectives. Use the questions to test their results and observations. Questions 4–6 cover the third learning objective and ask learners to explain the conditions required. Use question 7 to see if learners can connect this experiment to rates of reaction. To stretch learners, expand this question and ask them to write a full plan. Find the answers in the Teacher notes . 

How to use this resource

Set learners the first part of the experiment. It usually yields results within a lesson if the water is at the correct temperature and the reaction mixture is well mixed to begin with. It also depends on the freshness of the yeast. Dried yeast does work. If fermentation is not rapid because of the yeast used, then carry the whole experiment over to the next lesson.

For an alternative practical arrangement to part 1, use a bung and delivery tube to bubble the carbon dioxide through limewater. Or watch the Identifying ions practical video from 08:20 to see how to use a pipette to collect the gas when testing for carbonate ions. 

In the second part of the experiment, you can demonstrate distilling the reaction mixture. Watch the Fractional distillation  and Simple distillation videos and download the accompanying resources for setup, method and more learner-facing activities on simple distillation.

If you demonstrate distillation, pool the class results and filter the groups’ solutions into your distillation flask. Significant quantities of yeast will produce foaming and you can carry this over into the product if you do not filter the reaction mixture. Collect the fraction between 77–82°C. Ethanol boils at 78°C. This fraction should burn easily compared with the non-flammable original solution. Pour the ethanol away immediately and do not keep or reuse it.

Alternatively, set the distillation practical as a learner activity. Individuals or pairs may not produce enough ethanol to complete the distillation so learners may need to combine their solutions and work in groups.

More resources

• Use our  organic chemistry worksheet on alcohols  with 14–16 learners for practice in applying knowledge in context, including burning alcohols in cooking and as fuels.
• Link your lessons on fermentation and bioethanol to UN sustainable development goal 8 while developing learners’ literacy skills with this resource on  E10 petrol and climate change .
• Learn how a circular approach to manufacturing at British Sugar means there is virtually zero waste, including how they create coproducts such as bioethanol, by watching Paul’s  video job profile .
• Download the classroom activity and display the  fractional distillation  poster in your classroom to help 14–16 learners understand this important separating technique.

Technician notes

Read our  Standard health and safety guidance  and carry out a risk assessment before running any live practical.

Ensure learners wear safety glasses.

Be aware that if the fermentation is fast, the mixture may overflow from the flask.

Equipment (per group)

• 100 cm 3  conical flask
• 50 cm 3  measuring cylinder
• Boiling tube
• Boiling tube rack
• Access to a mass balance, correct to 1 decimal place
• Cotton wool – enough to plug the conical flask
• Safety glasses

Chemicals (per group)

• Glucose, 5 g – not currently classed as hazardous. See CLEAPSS Hazcard HC040c for more information.
• Yeast (as fast acting as possible), 1 g

Wear eye protection and measure 5 g of calcium hydroxide.

Add, while stirring, to 300 cm 3 of water in a large beaker.

Continue to stir the suspension, then pour it into a clean, labelled 2.5 dm 3 screw-top bottle using a funnel.

Fill the bottle with distilled water and tightly close the lid. Invert it to mix.

Leave the bottle overnight to allow the suspension to settle.

When required, slowly pour the limewater into small, labelled bottles.

Add more distilled water and/or calcium hydroxide to the stock bottle as required.

• 50 cm 3  of warm water 30–40°C
• Put 5 g of glucose in the conical flask and add 50 cm 3 of warm water. Swirl the flask to dissolve the glucose.
• Add 1 g of yeast to the solution and loosely plug the top of the flask with cotton wool.
• Wait while fermentation takes place. The time it takes will depend on the temperature, how well you mixed the reactants and the yeast’s freshness.
• Add 5 cm 3 of limewater to the boiling tube. Avoid contact with your skin as limewater is an irritant.
• Remove the cotton wool and pour the invisible gas into the boiling tube containing limewater. Take care not to pour in any liquid as well.
• Gently swirl the limewater in the boiling tube and note what happens.
• Replace the cotton wool in the top of the flask.

Source: © Royal Society of Chemistry

Set up the equipment as shown or use a pipette or bung and delivery tube instead of cotton wool to bubble the carbon dioxide through limewater

• Remove the cotton wool and note the smell of the solution.

If you are going to observe the distillation then you, or your teacher, will:

• Filter all the groups’ solutions into a distillation flask.
• Distil the mixture and collect the distillation fraction between 77–82°C.

The distillation fraction should easily burn.

Fermentation of glucose using yeast student sheet

Fermentation of glucose using yeast teacher notes, 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 . Updated in 2024 with additional student questions by Neil Goalby.

© Nuffield Foundation and the Royal Society of Chemistry

More Neil Goalby

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• 14-16 years
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• Biological chemistry
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Specification

• Ethanol is produced industrially by fermentation of glucose. The conditions for this process.
• Ethanol produced industrially by fermentation is separated by fractional distillation and can then be used as a biofuel.
• AT.3 Use of appropriate apparatus and techniques for conducting and monitoring chemical reactions, including appropriate reagents and/or techniques for the measurement of pH in different situations.
• Aqueous solutions of ethanol are produced when sugar solutions are fermented using yeast. Students should know the conditions used for fermentation of sugar using yeast.
• AT4 Safe use of a range of equipment to purify and/or separate chemical mixtures including evaporation, filtration, crystallisation, chromatography and distillation.
• 9.33C Describe the production of ethanol by fermentation of carbohydrates in aqueous solution, using yeast to provide enzymes
• 9.34C Explain how to obtain a concentrated solution of ethanol by fractional distillation of the fermentation mixture
• 3 Use of appropriate apparatus and techniques for conducting and monitoring chemical reactions, including appropriate reagents and/or techniques for the measurement of pH in different situations
• Use of appropriate apparatus and techniques for conducting and monitoring chemical reactions, including appropriate reagents and/or techniques for the measurement of pH in different situations
• (s) how ethanol (an alcohol) is made from sugars by fermentation using yeast

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Inflate a Balloon with Yeast Experiment

Did you know that you can inflate a balloon WITHOUT blowing air into it? It’s true.

In this simple experiment , young scientists use yeast to magically inflate a balloon. How cool is that?!

Check out the simple step-by-step below and then snag our 30 Science Experiments that are kid-approved!

Getting Ready

We headed into the kitchen to grab all of our supplies for this science experiment:

• Clear plastic or glass bottle with a narrow neck (a water bottle or soda bottle work great)
• 2 Tablespoons dry yeast
• 1 Tablespoon sugar
• 2-3 Tablespoons lukewarm water
• Party balloon
• Bowl or mug full of lukewarm water

Inflating a balloon with yeast is a wonderful experiment to do with preschool and kindergarten aged children because all of the materials are nontoxic. It’s nice when the kids can help measure out ingredients without worrying about what they are touching.

My kids helped me measure the yeast, sugar, and warm water into a cup.

They stirred the ingredients and then used a funnel to pour the brown mixture into the bottle. We added a little bit more water to help the yeast mixture get through the neck of the funnel.

We quickly stretched a balloon over the mouth of the bottle.

After placing the bottle into a mug full of warm water, we sat back to observe.

Inflate a Balloon with Yeast

Almost immediately, we observed bubbles in the yeast mixture.

I explained to the kids that yeast is a microscopic fungus that converts sugar into carbon dioxide.

The bubbles they saw were tiny bubbles of carbon dioxide gas that the yeast was producing as it “ate” the sugar.

For yeast to be active, it needs to be warm and moist. That’s why we added lukewarm water and placed the bottle in more warm water.

We set our bottle of yeast on the table and watched it while we ate lunch and read books.

We checked in with our science experiment every 10 minutes or so to observe any changes. Every time we looked, we noticed that the balloon was getting bigger and bigger on top of the bottle! Why?

As the yeast continued to react, it converted more and more sugar into carbon dioxide gas.

This gas was trapped in the balloon, making it inflate as if by magic!

It took about an hour for our balloon to reach its maximum size.

The yeast bubbled up into the bottle quite a bit before it stopped reacting and shrank down again. Simple science at its best.

More Fun for Little Scientists

Grab our 30 Science Experiments in our shop – complete with a no prep journal to record results!

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Science project, growing yeast: sugar fermentation.

Yeast is most commonly used in the kitchen to make dough rise. Have you ever watched pizza crust or a loaf of bread swell in the oven? Yeast makes the dough expand. But what is yeast exactly and how does it work? Yeast strains are actually made up of living eukaryotic microbes, meaning that they contain cells with nuclei. Being classified as fungi (the same kingdom as mushrooms), yeast is more closely related to you than plants! In this experiment we will be watching yeast come to life as it breaks down sugar, also known as sucrose , through a process called fermentation . Let’s explore how this happens and why!

What is sugar’s effect on yeast?

• 3 Clear glass cups
• 2 Teaspoons sugar
• Water (warm and cold)
• 3 Small dishes
• Permanent marker

• Fill all three dishes with about 2 inches of cold water
• Place your clear glasses in each dish and label them 1, 2, and 3.
• In glass 1, mix one teaspoon of yeast, ¼ cup of warm water, and 2 teaspoons of sugar.
• In glass 2, mix one teaspoon of yeast with ¼ cup of warm water.
• In glass 3, place one teaspoon of yeast in the glass.
• Observe each cups reaction. Why do you think the reactions in each glass differed from one another? Try using more of your senses to evaluate your three glasses; sight, touch, hearing and smell especially!

The warm water and sugar in glass 1 caused foaming due to fermentation. 

Fermentation is a chemical process of breaking down a particular substance by bacteria, microorganisms, or in this case, yeast. The yeast in glass 1 was activated by adding warm water and sugar. The foaming results from the yeast eating the sucrose. Did glass 1 smell different? Typically, the sugar fermentation process gives off heat and/or gas as a waste product. In this experiment glass 1 gave off carbon dioxide as its waste.

Yeast microbes react different in varying environments. Had you tried to mix yeast with sugar and cold water, you would not have had the same results. The environment matters, and if the water were too hot, it would kill the yeast microorganisms. The yeast alone does not react until sugar and warm water are added and mixed to create the fermentation process. To further investigate how carbon dioxide works in this process, you can mix yeast, warm water and sugar in a bottle while attaching a balloon to the open mouth. The balloon will expand as the gas from the yeast fermentation rises.

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Yeast-Air Balloons

The purpose of any leavener is to produce the gas that makes bread rise. Yeast does this by feeding on the sugars in flour, and expelling carbon dioxide in the process.

While there are about 160 known species of yeast, Saccharomyces cerevisiae, commonly known as baker's yeast, is the one most often used in the kitchen. Yeast is tiny: Just one gram holds about 25 billion cells. That amount of fungi can churn out a significant amount of carbon dioxide, provided it has the simple sugars it uses as food. Fortunately, yeast can use its own enzymes to break down more complex sugars—like the granulated sugar in the activity below—into a form that it can consume.

Make a yeast-air balloon to get a better idea of what yeast can do.

Did You Know?

What do i need.

1 packet of active dry yeast

1 cup very warm water (105° F-115° F)

2 tablespoons sugar

a large rubber balloon

a small (1-pint to 1-liter) empty water bottle

Kids, please don t try this at home without the help of an adult.

What do I do

Stretch out the balloon by blowing it up repeatedly, and then lay it aside.

Add the packet of yeast and the sugar to the cup of warm water and stir.

Once the yeast and sugar have dissolved, pour the mixture into the bottle. You ll notice the water bubbling as the yeast produces carbon dioxide.

Attach the balloon to the mouth of the bottle, and set both aside.

Step 5: After several minutes, you ll notice the balloon standing upright. If you don t see anything happen, keep waiting. Eventually, the balloon will inflate.

What's going on.

As the yeast feeds on the sugar, it produces carbon dioxide. With no place to go but up, this gas slowly fills the balloon.

A very similar process happens as bread rises. Carbon dioxide from yeast fills thousands of balloonlike bubbles in the dough. Once the bread has baked, this is what gives the loaf its airy texture.

What Else Can I Try?

Try the same experiment, but this time use about a tablespoon of baking powder instead of yeast, and leave out the sugar. What differences do you notice? Which leavener takes longer to fill up the balloon?

Also, try the same experiment using hotter and colder water. Use a thermometer to measure the temperature of the water. At what temperature is the yeast most active? At what temperatures is it unable to blow up the balloon?

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Blow up a balloon with yeast, you will need.

A packet of yeast (available in the grocery store) A small, clean, clear, plastic soda bottle (16 oz. or smaller) 1 teaspoon of sugar Some warm water A small balloon

1. Fill the bottle up with about one inch of warm water. ( When yeast is cold or dry the micro organisms are resting.) 2. Add all of the yeast packet and gently swirl the bottle a few seconds. (As the yeast dissolves, it becomes active – it comes to life! Don’t bother looking for movement, yeast is a microscopic fungus organism.) 3. Add the sugar and swirl it around some more. Like people, yeast needs energy (food) to be active, so we will give it sugar. Now the yeast is “eating!”

4. Blow up the balloon a few times to stretch it out then place the neck of the balloon over the neck of the bottle. 5. Let the bottle sit in a warm place for about 20 minutes If all goes well the balloon will begin to inflate!

How does it work?

As the yeast eats the sugar, it releases a gas called carbon dioxide. The gas fills the bottle and then fills the balloon as more gas is created. We all know that there are “holes” in bread, but how are they made? The answer sounds a little like the plot of a horror movie. Most breads are made using YEAST. Believe it or not, yeast is actually living microorganisms! When bread is made, the yeast becomes spread out in flour. Each bit of yeast makes tiny gas bubbles and that puts millions of bubbles (holes) in our bread before it gets baked. Naturalist’s note – The yeast used in this experiment are the related species and strains of Saccharomyces cervisiae. (I’m sure you were wondering about that.) Anyway, when the bread gets baked in the oven, the yeast dies and leaves all those bubbles (holes) in the bread. Yum.

MAKE IT AN EXPERIMENT

The project above is a DEMONSTRATION. To make it a true experiment, you can try to answer these questions:

1. Does room temperature affect how much gas is created by the yeast? 2. Does the size of the container affect how much gas is created? 3. What water/room temperature helps the yeast create the most gas? 4. What “yeast food” helps the yeast create the most gas? (try sugar, syrup, honey, etc.)

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• Fermentation, or how to blow up a balloon with yeast!

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If you have ever baked bread, you probably have encountered yeast and used it to make the dough rise. But how does it work? The yeast you can buy in a shop is called Saccharomyces cerevisiae , or just baker’s yeast. Yeasts break down sugars and produce alcohol, which is used in alcoholic beverages, and carbon dioxide, which is a gas that makes bread dough rise.

You can see the fermentation process in a very easy way at home, by mixing some active dry yeast, sugar and warm water in an empty bottle and fit a balloon over the bottle top. Watch the balloon blow up magically!

Here is how you can do it: 

• Packet of yeast
• Empty Water Bottle
• Funnel 

Use the funnel  to put a couple of spoonfuls of sugar in an empty water bottle. 

Fill half of the bottle with warm water.

Add a package of yeast. Yeast is activated when it gets wet. So, put the top on and shake the bottle. Open the bottle again and place the ballon over the bottle opening. 

Finally you wait for the magic to happen. It will take more than an hour to get the balloon really good and inflated.

But how does this work? Yeast  is a microscopic fungus. As the yeast eats the sugar, it releases a gas called carbon dioxide. The gas fills the bottle and then fills the balloon as more gas is created.

Tips for the experiment and food for thought:

• Try to use clear bottles, so you can see the liquid bubbling!
• Try repeating the experiment with cold water. Or, putting the bottles in a warm place like a sunny window sill. Does the temperature influence the activity of the yeast?
• Try adding different amounts of sugar (or no sugar!) to the mixture. Which bottles grow the balloon most?
• Can yeast use other sugars than sucrose (which is the sugar in household sugar)? How about using some fruit juice (with a lot of fructose) or milk (with lactose)?
• When the balloons are all blown up, don’t forget to take a whiff before throwing it away! What does the smell remind you of? How do different bottles differ in their smell?

If you want to see a video with the experiment click here . 

The same process happens when we are making bread. Check this video to find out more.

By Daniel Sachs

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Yeast Balloon Experiment

Updated: Sep 29, 2022 · This post may contain affiliate links.

Can you inflate a balloon with yeast? You sure can! Let's learn how with this simple and fun science experiment for kids.

Yeast Balloon Experiment - Step by Step

What did we learn, expand the experiment, more stem activities for kids.

When you think of yeast, you probably think of baking. But this little ingredient makes for some great science experiments as well!

This yeast balloon experiment is:

• A fun STEM activity for kids of all ages.
• Simple to do with ingredients you probably already have!
• Quick, easy and fun.

Start by filling a large mixing bowl with warm water. It only needs to be lukewarm - not very hot.

Next mix instant yeast, sugar, and warm water together in a glass bottle or flask with a narrow neck (like this Erlenmeyer Flask) . If you don't have one, you can use any bottle or container with a narrow neck. Even a disposable water bottle will work in a pinch. You need to be able to stretch the balloon over the opening!

Place the glass bottle into the bowl of warm water to keep it warm. Stretch the balloon over the opening of the bottle.

Sit back and watch what happens! You should see the balloon slowly begin to inflate. How long does it take for the balloon to inflate?

Yeast is a living organism! And it loves to eat sugar. As the yeast consumes the sugar in your mixture, it converts the sugar into alcohol and carbon dioxide gas. The balloon inflates from the carbon dioxide gas!

This is the same process that is at work when you bake bread or other baked goods with yeast. The yeast consumes sugar, and releases carbon dioxide, which causes your dough to rise. Cool, huh?

Try the experiment a few more times, with varying amounts of sugar and yeast. What combination inflates the balloon to the largest size? Why do you think that happens?

Try again using cold water instead of warm water. Does the balloon still inflate? Why or why not?

If you love this yeast balloon experiment, check out these other fun activities for kids:

• Microwave Ivory Soap - An Easy Experiment!
• STEM Activities for Elementary Kids
• Best Science Experiments for Kids

• 2 tbsp instant dried yeast
• 1 tbsp sugar
• 2 tbsp warm water
• additional warm water
• large mixing bowl
• glass flask or bottle with a narrow neck

Instructions

Fill a large mixing bowl with warm water. Mix the instant yeast, sugar, and 2 tbsp warm water together in the glass bottle or flask. Place the glass bottle into the bowl of warm water to keep it warm. Stretch the balloon over the opening of the bottle. Wait and watch the balloon inflate!

The water should be warm enough to activate the yeast, but does not need to be very hot.

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Yeast Balloon Experiment

Share with your friends!

Check out this super cool experiment that uses the expanding power of yeast to inflate a balloon! You and your kids will love doing this Yeast Balloon Experiment together.

Get more amazing Balloon Science Experiments here!

This is a mind-blowing (and balloon blowing) way to learn about the common reaction of yeast, sugar, and water!

Table of Contents

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Supplies Needed:

• A Plastic Bottle

How to Inflate a Balloon With Yeast

• Fill a plastic bottle with about 1 inch of warm water.
• Pour in about 1 tablespoon of yeast and gently shake the bottle up a little bit.
• Add a teaspoon of sugar and swirl the bottle around a little more.
• Slide the neck of the balloon over the opening of the bottle.
• Let the yeast work its magic for about 15-20 minutes. The balloon should slowly start to inflate!

Step 1: Pour Warm Water Into a Plastic Bottle

I prefer to use a clear plastic bottle for this so that you can see the reaction of the rising yeast inside, but you really can use any type of small empty water bottle for this.

The important part is to pour enough warm water into the bottle so that that the water is about an inch deep inside the bottle.

If you bake with yeast often, then you will already know that the water needs to be warm, but not too warm or it will kill the yeast (I had to learn this from my wife who does the baking in our family).

Step 2: Add Some Yeast Into The Bottle

If you have the small little packets of yeast, you can dump one of those into the bottle, or you can measure and pour about 1 tablespoon of yeast from a large packet of yeast.

Using a funnel will make this a little easier and a little less messy to get the yeast inside the bottle.

Step 3: Add Some Sugar

Measure and pour about 1 teaspoon of sugar into your bottle of yeast and warm water. Again, using a funnel will help you get less sugar on the counter and more sugar into the bottle.

Step 4: Attach The Balloon to The Bottle

Quickly, but carefully connect a large balloon to the opening of the bottle. It may help to inflate and then deflate the balloon first just to stretch it out a little bit.

Then slide the mouth of the balloon over the opening of the bottle. Make sure the balloon is snug and sealed onto the bottle to prevent any air from escaping between the bottle and the balloon.

Give the bottle a little swirl or shake to mix the warm water, yeast, and sugar together. This should start the classic yeast reaction that we need for this experiment!

Step 5: Wait Patiently For The Reaction to Inflate The Balloon

The hardest part of this experiment is waiting 15-20 minutes for the reaction to happen and inflate the balloon…but I promise it will be worth it!

So set the balloon and bottle in a safe and secure place, go grab a snack and come back in a few minutes to check on it.

You can also try doing what I did and setting up your phone or camera for a time-lapse video of the reaction. It’s super fun to go back and watch the reaction inflate the balloon with the time-lapse.

After a good 15 or 20 minutes, the yeast, water and sugar should have reacted and expanded inside the bottle, and the balloon will inflated too!

Yeast Balloon Experiment Conclusion

The science behind this yeast balloon experiment is related to the same reason yeast is used in many bread, dough, and baking recipes!

Yeast is a single-celled organism described as a “sugar-eating fungus”. Yeast needs food, warmth, and moisture to thrive and grow.

As the yeast grows and converts the sugar into energy, it releases Carbon Dioxide gas in a process called fermentation .

The tiny little carbon dioxide (CO2) gas bubbles get trapped in bread dough as it bakes and is what makes bread so soft and spongy!

Now in our experiment, the warm water in the bottle provides warmth and moisture for the yeast, while the sugar provides the food for the yeast to grow and expand.

The addition of carbon dioxide in the bottle increases the air pressure in the bottle, which pushes air into the balloon and inflates it!

This Baking Soda and Vinegar Balloon Experiment is also another fun way to inflate a balloon if can’t find any yeast in your kitchen cabinets!

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More Fun Experiments For Kids:

• Dancing Grapes Experiment
• How to Make a Bottle Gun
• Cloud in a Bottle Experiment With Rubbing Alcohol

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Inflate a Balloon with Yeast Fermentation Experiment: Lab Explained

• Inflate a Balloon with Yeast…

INTRODUCTION

Yeasts are eukaryotic, single-celled microorganisms that belong to the fungal kingdom. When yeasts consume sugar and convert it to energy, they emit carbon dioxide, this is referred to as fermentation. The yeast will be more active and develop faster if there is more sugar present. While sugar and other sweets provide “food” for yeast, too much sugar can harm it by draining moisture from it and preventing it from growing. Too much sugar also delays the development of gluten. Increase the amount of yeast in the recipe or find a comparable recipe with less sugar.

Sweet yeast doughs will rise more slowly. Fermentation is sped up by a small amount of sugar, up to 3%. Warm water makes yeast grow, cold water has the reverse effect, and hot water kills yeast. Temperatures ranging from 0 to 47 degrees Celsius are suitable for yeast growth. Yeasts flourish in acidic settings with pH levels between 4.0 and 4.5. They can grow in lower pH environments than other bacteria, but not in alkaline environments. Yeasts are common in nature and can be found on grapes and other fruits. All yeast need food, moisture, and a controlled temperature environment in order to ferment. Its byproducts from food consumption include carbon dioxide, alcohol, and other organic molecules.

comparing yeast growth at various sugar concentrations.

• 50ml of water
• Two balloons

(funnel may be needed to safely transfer the ingredients into the water bottles)

• A kettle was used to boil the water, then cold water was added to the boiling water to get lukewarm water.
• 50ml of lukewarm water was added to each bottle.
• ¼ teaspoon of table sugar was then added to the first water bottle, then ½ teaspoon of table sugar was added to the other water bottle.
• ½ teaspoon of rapid-rise yeast was then added to each solution and mixed.
• After mixing, a balloon was placed on each water bottle/ tube and sealed securely.
• The contents were mixed periodically.

(N.B- A string may be used to seal the balloon placed on water bottles).

OBSERVATIONS

During the experiment, 500ml water bottles were used. Then 50ml of lukewarm water was added to each bottle, after that, ½ teaspoon of sugar was added to the 1 st bottle then ¼ teaspoon of sugar was added to the 2 nd bottle. Finally, ½ teaspoon of rapid-rise yeast was added to both bottles, then the balloons were placed on each tube and securely sealed. The balloons were checked at the time interval of 15min to observe any changes, when glancing at the balloons, it was noticed that the balloons were getting bigger and bigger every time on top of the water bottles. Warmth and moisture are necessary for yeast to function, that is why lukewarm water was added. Sugar was converted to carbon dioxide by yeast.

Some bubbles were also observed in the yeast mixture during the experiment, it was the small carbon dioxide gas bubbles produced by the yeast as it “ate” the sugar.

As the yeast continued to react, additional sugar was transformed into carbon dioxide gas. The balloons were filled with this gas, which caused them to inflate. It was also observed that the balloon on the water bottle that had ½ teaspoon of sugar was growing bigger at a faster rate than the one that had ¼ teaspoon of sugar.

This can show that glucose concentration increases fermentation production in yeast. The more sugar present, the more active the yeast becomes, and the faster it grows. The balloon on the bottle that had less sugar was growing at a slow rate compared to the other one, even had fewer bubbles visible. It was seen that the concentration of sugar plays a vital role in the rate of fermentation, the more sugar present, the more active the yeast becomes, and the faster it grows. This also showed why the fermentation rates of the sugars differ over time. Both balloons grew until they reached a point where they grew no more.

During the experiment, when the balloons were growing bigger and bigger, using the time interval of 15 minutes, the circumferences of the balloons were measured. From the measurements, it can be safely concluded that the balloon on the water bottle with ½ teaspoon of sugar grew bigger and faster than the one on the water bottle with ¼ teaspoon of sugar. Another thing observed is that as time went by the fermentation rate of both the balloons started to decrease.

From what was observed during the practice of the experiment, it can be concluded that the more sugar there is, the more active the yeast will be and the faster its growth. THIS CAN BE APPLIED IN REAL LIFE: fermentation can be used to preserve food, preventing rotting or harmful microorganisms from growing in the food. Can also apply when baking bread.

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Grow yeast experiment

Follow FizzicsEd 150 Science Experiments:

You Will Need:

• 4 packets of dry yeast
• 4 water bottles, chilled in the fridge (we use Thank You Water, a social enterprise that works to get clean water & sanitation to people in need)
• 1 large jug.
• 4 measuring cups.
• 4 thermometers (one will do if you don’t have a class set).
• Access to boiling water plus adult supervision.
• 1 stopwatch.
• A pen to mark the water temperature on each water bottle during the experiment.
• A shelf to leave the science experiment to run.
• A notebook for your observations.

• Instruction

Pour out the 4 chilled water bottles into the large jug and discard the rest of the water (maybe water your  school garden !)

Carefully measure out the water into the four measuring cups as per the measurements below;

Cup 1 – 200mL of chilled water

Cup 2 – 150mL of chilled water

Cup 3 – 100mL of chilled water

Cup 4 – 50mL of chilled water

Use the thermometers to take a measurement of the water temperature in each cup (write this in your notebook).

With an adult, boil a jug of water and then top up cups 2, 3 and 4 so that they too have 200mL of water as per cup 1. You will be testing the effect of temperature on the growth of yeast by measuring how much gas is released by the yeast under 4 different temperature conditions ( variable testing ).

Using a funnel, carefully pour each cup of water into the four separate water bottles. Use the pen to mark the starting temperature of each water bottle.

Add a spoonful of sugar per water bottle and then swirl the bottle to dissolve the sugar.

Add a yeast packet into each bottle and quickly stretch a balloon of the opening of each bottle.

4 yeast growth experiments started, showing a distinct change already!

Start the stopwatch and take notes of when each balloon rises!

OPTIONAL: you could also keep each bottle in the yeast experiment at the same temperature and vary the amount of sugar added instead.

Go further – buy 4 x student activity sheets as extension worksheets.

This student science booklet has been created by experienced science educators from the Fizzics Education team.

Use these student worksheets as blackline masters for your science class!

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What is going on?

Your experiment was testing the effect of water temperature on the growth of yeast. Yeast are egg-shaped microscopic cells of fungi that are dormant whilst kept in dry and cool conditions. However, yeast will rapidly divide once exposed to water and sugar in ideal temperatures. In the right temperature, yeast cells will change the sugar into glucose by using the water plus as an enzyme catalyst (invertase). Once the yeast has converted the sugar to glucose fermentation can then occur to produce carbon dioxide and ethanol as per the equation below;

Glucose ⟶ Ethanol + Carbon dioxide

which can be written as…

C 6 H 12 O 6(aq)   ⟶ 2C 2 H 5 OH (aq)  + 2CO 2(g)

In your experiment, you were trapping the carbon dioxide released during the fermentation process. The more active the yeast, the more carbon dioxide the yeast produced! In your experiment, the different water temperatures will have produced different results as bottles may have been too hot for the yeast to survive whereas the other bottles may have been too cold.   By introducing a variable to test in your experiment, you’re doing real science!  The following list of temperatures is worth keeping in mind when assessing your results:

• 55° C – 60° C Yeast cells die (also known as the thermal death point).
• 41° C – 46° C Ideal temperature of water for dry yeast being reconstituted with water and sugar.
• 4° C The temperature of a fridge – yeast will be too cold to work properly.

Yeast is used to make bread rise and to ferment beer. There are many different species of yeast, but the one most commonly used in cooking and baking is called  Saccharomyces cerevisiae , which is also known as brewer’s yeast.

Yeast can break down many types of simple carbohydrates (monosaccharides) however they cannot break down complex carbohydrates such as starch. This means that extra enzymes are needed to break down starch into sugars that the yeast can use, for example during beer production we use enzymes from germinating barley to do this.

Variables to test

More on variables here

• Try different concentrations of vinegar as the growth medium. Can the yeast handle some acidity?
• Vary the amount of sugar used.
• Does the volume of water make a difference?

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4 thoughts on “ Grow yeast experiment ”

What is the amount of water you would like me to put?

Hi! Here’s the detail’s that you need;

> Cup 1 – 200mL of chilled water > Cup 2 – 150mL of chilled water > Cup 3 – 100mL of chilled water > Cup 4 – 50mL of chilled water

With an adult, boil a jug of water and then top up cups 2, 3 and 4 so that they too have 200mL of water as per cup 1. You will be testing the effect of temperature on the growth of yeast by measuring how much gas is released by the yeast under 4 different temperature conditions.

Would this experiment still work if instead i tested how different types of sugars affect the amount of fermentation by yeast. Would i still get different sized balloons in my result.

We’d love it if you try this and let us know! With any experiment you just have to change one thing and then measure the result. So, changing the types of sugars is a completely valid investigation. Good luck!

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Shop Experiment Sugar Fermentation by Yeast Experiments​

Sugar fermentation by yeast.

Experiment #24 from Investigating Chemistry through Inquiry

Introduction

Yeast can metabolize sugar in two ways, aerobically , with the aid of oxygen, or anaerobically , without oxygen. When yeast metabolizes a sugar under anaerobic conditions, ethanol (CH 3 CH 2 OH) and carbon dioxide (CO 2 ) gas are produced. An equation for the fermentation of the simple sugar glucose (C 6 H 12 O 6 ) is:

The metabolic activity of yeast can be determined by the measurement of gas pressure inside the fermentation vessel.

In the Preliminary Activity, you will use a Gas Pressure Sensor to monitor the pressure inside a test tube as yeast metabolizes glucose anaerobically. When data collection is complete, you will perform a linear fit on the resultant graph to determine the fermentation rate.

After completing the Preliminary Activity, you will first use reference sources to find out more about sugar fermentation by yeast before you choose and investigate a researchable question dealing with fermentation.

Sensors and Equipment

This experiment features the following sensors and equipment. Additional equipment may be required.

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This experiment is #24 of Investigating Chemistry through Inquiry . The experiment in the book includes student instructions as well as instructor information for set up, helpful hints, and sample graphs and data.

Kids Kitchen: Yeast Science Experiment for Kids

Welcome to Sugar, Spice & Glitter! Please note, this post may contain affiliate links. For more details, see our Full Disclosure .

Welcome back to Sugar, Spice & Glitter! Please note, this post may contain affiliate links. For more details, see our Full Disclosure .

We’re interrupting our usual schedule of kids’ activities , parenting inspiration , and family-friendly food to bring you 31 days of Kids Kitchen Recipes and Activities.

Usually, we activate yeast in a mixture of warm water, sugar, and salt, but I wanted to see what would happen if we tried to activate yeast with only one or two of those other components. This teaches kids the importance of temperature and environment in producing chemical reactions.

Kitchen Science Experiment Materials:

I presented Ella with this tray consisting of:

• 5 baby food jars (would have been better with 6 but I could only find 5!)
• 2 teaspoons of sugar
• 2 teaspoons of salt
• 4 teaspoons of dry yeast

And I also had measuring cups with cold and warm water on the side.

We discussed what we knew about yeast and what we thought would happen if we combined the yeast in different ways, and designed our experiment together.

This very simple discussion lays a foundation of understanding the scientific method.

We decided to create the following conditions to attempt to activate the yeast within:

• 2 oz cold water and 1 teaspoon sugar
• 2 oz cold water and 1 teaspoon salt
• 2 oz warm water
• 2 oz warm water and 1 teaspoon sugar
• 2 oz warm water and 1 teaspoon salt

We stirred one teaspoon of yeast vigorously into each jar until the yeast was mostly dissolved and then waited five minutes – the length of time we usually have to wait when using yeast in recipes.

Kids Kitchen Science Experiment Results:

After waiting five minutes, we observed and compared the contents of the jars using lots of descriptive language like frothy, flat, cloudy, opaque, clear, etc.

We discovered that the warm water with a bit of salt was the best environment for activating the yeast, but that just warm water alone was not enough to activate the yeast very much, and that warm water and sugar was better than cold water and salt.

This was great for showing Ella – my little chef – how it is sometimes the combination of factors that can produce best results, and will hopefully encourage her to explore further why recipes sometimes encourage ingredients to be at room temperature.

The very basis of baking is chemistry, so sometimes looking at a simple reaction like yeast activation can encourage children to explore the science of baking and can encourage children who love baking to take an interest in science.

I hope you have a chance to give this kitchen science experiment a try — make sure to pin it for later!  Check out the rest of our 31 Days of Kids Kitchen Series here.

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3.1.3 Yeast experiment explained

You’ve seen the results of the yeast experiment, but what do these results mean?

Yeasts are microscopic, single-celled organisms, and are a type of fungus that is found all around us, in water, soil, on plants, on animals and in the air. Like all organisms, when yeasts are put in the right type of environment they will thrive; growing and reproducing.

Your experiments were designed to help you identify which environment promotes the most yeast growth. The first three glasses in your experiment contained different temperature environments (cold water, hot water and body temperature water). At very low temperatures the yeast simply does not grow but it is still alive – if the environment were to warm up a bit, it would gradually begin to grow. At very high temperatures the cells within the yeast become damaged beyond repair and even if the temperature of that environment cooled, the yeast would still be unable to grow. At optimum temperatures the yeast thrives.

Your third and fourth glasses both contained environments at optimum temperature (body temperature) for yeast growth, the difference being, the fourth glass was sealed. The variable between these two experiments was the amount of available oxygen. You may have been surprised by your results here, thinking that a living organism in an environment without oxygen cannot survive? However, you should have found that yeast grew pretty well in both experiments.

To understand why yeast was able to thrive in both conditions we need to understand the chemical process occurring in each glass during the experiment. In the three open glasses, oxygen is readily available, and from the moment you added the yeast to the sugar solution it began to chemically convert the sugar in the water and the oxygen in the air into energy, water, and carbon dioxide in a process called aerobic respiration.

Yeast is a slightly unusual organism – it is a ‘facultative anaerobe’. This means that in oxygen-free environments they can still survive. The yeast simply switches from aerobic respiration (requiring oxygen) to anaerobic respiration (not requiring oxygen) and converts its food without oxygen in a process known as fermentation. Due to the absence of oxygen, the waste products of this chemical reaction are different and this fermentation process results in carbon dioxide and ethanol.

Depending on how long you monitored your experiment for and how much space your yeast had to grow you may have noticed that, with time, the experiment sealed with cling film slowed down. This is for two reasons; firstly because less energy is produced by anaerobic respiration than by aerobic respiration and, secondly, because the ethanol produced is actually toxic to the yeast. As the ethanol concentration in the environment increases, the yeast cells begin to get damaged, slowing their growth.

The ethanol produced is a type of alcohol, so it is this process that allows us to use it to make beer and wine. When used in bread making, the yeast begins by respiring aerobically, the carbon dioxide from which makes the bread rise. Eventually the available oxygen is used up, and the yeast switches to anaerobic respiration producing alcohol and carbon dioxide instead. Do not worry though; this alcohol evaporates during the baking process, so you won’t get drunk at lunchtime from eating your sandwiches.

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18 Easy Science Experiments for Kids

By Med Kharbach, PhD | Last Update: June 30, 2024

Effective learning is driven by a sense of motivation, engagement, and challenge. Each of these aspects is interconnected and works symbiotically to create optimal learning experiences. When it comes to science, engagement isn’t always straightforward, and many science teachers still rely on the “storehouse model” (Karen, Roberts & Malcolm, 1991 ), where students are encouraged to store facts for future use.

While the storehouse model might work in certain areas, it doesn’t enhance understanding and critical analysis. Embrace constructionist approaches and hands-on learning to help kids develop inquiry skills and explore the world beyond their textbooks.

Easy Science Experiments for Kids

Science experiments are a fantastic way to embody inquiry skills such as questioning, observing, and reflecting. These hands-on activities encourage kids to become active participants in their learning journey. By engaging in experiments, children learn to ask questions about the world around them, make observations, and reflect on their findings. This process helps them develop critical thinking and problem-solving skills, fostering a deeper understanding of scientific concepts. Needless to mention that these experiments transform the act of learning from passive absorption of information to an active construction of knowledge, making science both fun and educational.

Below is a collection of practical science experiments for kids that foster essential inquiry skills like questioning, observing, and reflecting, transforming learning into an active and engaging process.

1. Rainbow Density Jar

Create a colorful density experiment by layering sugar-water solutions of different colors and concentrations. Kids will learn about density and buoyancy as they see the layers stack without mixing.

• Age Group : 6-8 years
• Materials : Sugar, food coloring, water, clear jars, spoons
• Educational Insight : Demonstrates liquid density
• Safety Tips : Handle sugar solutions carefully to avoid spills

2. Balloon Rocket

Showcase Newton’s Third Law by attaching a balloon to a straw on a string. When the balloon is released, it propels along the string, illustrating action and reaction forces.

• Age Group : 9-12 years
• Materials : Balloons, string, straws, tape
• Educational Insight : Explains Newton’s Third Law
• Safety Tips : Supervise balloon use to prevent popping near faces

3. Homemade Lava Lamp

Explore immiscibility and chemical reactions with a lava lamp made from water, oil, food coloring, and Alka-Seltzer tablets, creating mesmerizing movements.

• Age Group : 3-5 years
• Materials : Water, vegetable oil, food coloring, Alka-Seltzer, clear bottle
• Educational Insight : Shows oil and water immiscibility
• Safety Tips : Ensure materials are not ingested

4. Solar Oven S’mores

Teach solar energy principles by making s’mores in a homemade solar oven. Kids learn about heat absorption and renewable energy through this delicious experiment.

• Materials : Cardboard box, aluminum foil, plastic wrap, black paper, s’mores ingredients
• Educational Insight : Explains solar energy
• Safety Tips : Monitor to prevent overheating

5. Static Electricity Dancing Ghosts

Use static electricity to make tissue paper ghosts “dance” by rubbing a balloon on hair and bringing it close to the ghosts, illustrating static electric forces.

• Materials : Tissue paper, balloon, scissors
• Educational Insight : Demonstrates static electricity
• Safety Tips : Supervise balloon use to avoid accidental popping

6. Egg Drop Challenge

This experiment involves designing a contraption to protect an egg from breaking when dropped from a height. It encourages creativity and understanding of impact force and material properties.

• Materials : Eggs, straws, tape, cardboard, cotton, etc.
• Educational Insight : Teaches about impact force and engineering design
• Safety Tips : Ensure eggs are handled carefully to avoid mess

7. Invisible Ink

Use lemon juice to write secret messages that become visible when heated. This classic experiment introduces children to the concept of acid-base reactions and oxidation.

• Materials : Lemon juice, paper, cotton swab, heat source
• Educational Insight : Demonstrates acid-base reactions
• Safety Tips : Supervise the use of heat sources

8. Baking Soda Volcano

Create a volcanic eruption using baking soda and vinegar, providing a hands-on demonstration of chemical reactions and gas production.

• Materials : Baking soda, vinegar, dish soap, food coloring, container
• Educational Insight : Teaches chemical reactions
• Safety Tips : Conduct in a well-ventilated area

9. Magic Milk

Add drops of food coloring to milk and watch the colors move when soap is added. This experiment illustrates surface tension and the properties of different liquids.

• Materials : Milk, food coloring, dish soap, cotton swabs
• Educational Insight : Explains surface tension

10. Crystal Growing

Grow beautiful crystals using a salt or sugar solution. This experiment helps kids understand the process of crystallization and the properties of solutions.

• Materials : Salt/sugar, water, jar, string, pencil
• Educational Insight : Demonstrates crystallization
• Safety Tips : Handle boiling water with care

11. Oobleck

Make a non-Newtonian fluid called oobleck using cornstarch and water. It behaves like a solid when you apply force and like a liquid when at rest, demonstrating unique fluid properties.

• Materials : Cornstarch, water, bowl
• Educational Insight : Explores non-Newtonian fluids
• Safety Tips : Supervise to prevent ingestion and spills

12. Simple Circuit

Create a simple electrical circuit using a battery, wire, and a small bulb. This experiment introduces basic principles of electricity and circuitry.

• Materials : Battery, wires, small light bulb
• Educational Insight : Teaches basic electrical concepts
• Safety Tips : Supervise handling of electrical components

13. Balloon-Powered Car

Construct a small car powered by the air released from a balloon. This fun project demonstrates the principles of air propulsion and Newton’s Third Law of Motion.

• Materials : Balloons, straws, bottle caps, cardboard
• Educational Insight : Explains air propulsion
• Safety Tips : Ensure parts are securely attached to avoid choking hazards

14. Leaf Chromatography

Explore the pigments in leaves by separating them using chromatography. This experiment shows the different pigments that make up the color of leaves.

• Materials : Leaves, rubbing alcohol, coffee filters, jars
• Educational Insight : Demonstrates chromatography
• Safety Tips : Use rubbing alcohol with supervision

15. Elephant Toothpaste

Create a foamy eruption using hydrogen peroxide, yeast, and dish soap. This exciting experiment demonstrates rapid decomposition and gas production.

• Materials : Hydrogen peroxide, yeast, dish soap, food coloring, bottle
• Educational Insight : Explains chemical reactions and catalysts
• Safety Tips : Handle hydrogen peroxide with care and use gloves

16. Bouncy Egg

Soak an egg in vinegar for a few days to remove the shell, leaving a bouncy, rubber-like egg. This experiment demonstrates chemical reactions between acids and calcium carbonate.

• Materials : Eggs, vinegar, jar
• Educational Insight : Shows acid-base reactions
• Safety Tips : Handle the egg gently to avoid mess

17. Bottle Rocket

Create a simple rocket using a plastic bottle, baking soda, and vinegar. This experiment illustrates chemical reactions and Newton’s Third Law of Motion.

• Materials : Plastic bottle, baking soda, vinegar, cork, paper towels
• Educational Insight : Demonstrates propulsion and chemical reactions
• Safety Tips : Conduct outdoors and supervise closely

18. Static Electricity Butterfly

Create a paper butterfly that moves using static electricity from a balloon. This experiment helps kids understand static charges and attraction.

• Materials : Tissue paper, balloon, string
• Educational Insight : Explains static electricity
• Safety Tips : Supervise balloon use

For more science resources, check out:

• 20 Amazing Science Facts for Kids
• 15 Great Science Websites for Middle School
• 7 Great Science Posters for Classroom
• 10 Best Science Games for Kids

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Meet Med Kharbach, PhD

Dr. Med Kharbach is an influential voice in the global educational technology landscape, with an extensive background in educational studies and a decade-long experience as a K-12 teacher. Holding a Ph.D. from Mount Saint Vincent University in Halifax, Canada, he brings a unique perspective to the educational world by integrating his profound academic knowledge with his hands-on teaching experience. Dr. Kharbach's academic pursuits encompass curriculum studies, discourse analysis, language learning/teaching, language and identity, emerging literacies, educational technology, and research methodologies. His work has been presented at numerous national and international conferences and published in various esteemed academic journals.

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