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Science Rocks!



your results

Sent in by:
JJ of CA

It's alive!

Materials Needed

  • 1 package of yeast
  • warm water
  • 1 teaspoon sugar
  • spoons
  • large bowl



  1. Check with a grown-up before you begin.
  2. Does yeast seem alive to you? Well, it is. It just needs warmth and sugar to become active. Yeast are living things that are so small they only have one cell. They can't make their own food. So, if you don't give them food, they don't become active. It's almost like they are asleep. This is called being dormant. But when you make it warm for them and give them some food (yeast like sugar) they become active.
  3. Check it out:
  4. Pour one package of yeast in a large bowl.
  5. Add 1/4 cup of warm water and 1 teaspoon sugar.
  6. Now wait about 10 minutes. When you check it, you should see bubbles.
  7. The bubbles you see are carbon dioxide. The yeast eats the sugar and then makes carbon dioxide. The yeast also makes more yeast, which makes even more carbon dioxide. This is why yeast is used to make bread. The carbon dioxide produced by the yeast makes bubbles in the bread dough making it bigger and fluffier. But don't take our word for it, check out the recipe for Homemade Bread in the CafeZOOM section of the site.

Don't forget to try this out and tell us what you observe!

Some of your Results

Courtney, age 12 of Waterford, MI wrote:
It was really cool we did this experiment in science about yeast. Did you know yeast is a living thing? We tested to see if it actually can breath. And it can. AWSOME

Hadley, age 10 of New Underwood, SD wrote:
We put hot water and a little extra sugar and it over flowed at 8 minutes. IT WAS SSSSSSOOOOOOOOOO cool!!!

Greg of Killeen, TX wrote:
not much visible things happened but if you put the yeast in hydrogen peroxide (with an adult) is realy realy fizzes

Mike, age 10 of Atlanta, GA wrote:
well it did not do enything ant ferst but it greouw 5'in in 30 mi and it is stinky

Genessi of Virginia Beach, VA wrote:
Woah!!! Yo this is was a weird experiment I added more sugar than I was supposed too and YO it overflowed all over my kitchen table! LOL!

Talia, age 9 wrote:
it took 10 minutes just like you said!

Alexandra, age 12 of Vancouver wrote:
I put a lot of sugar in with the yeast and it over flowed, then when all over the counter top! It was sssssoooo cool!

Damani, age 11 of Washington, DC wrote:
When we added water sugar and yeast. It fizzled an rows from the water and stood byitself.

Ronnita, age 10 of Washington, DC wrote:
when we did it the yeast and the water and sugar it didn't do nothing. Then it started to foam up and started smell like bread.

Daysjar, age 10 of Washington, DC wrote:
When I did the experiment the yeast, and water started to rise because the C02 was starting to push theyeast up to the top of the cup.

Amari, age 10 of Washington, DC wrote:
The thing that happened was that the yeast started to rise. Then it started to get foamy. Then the foam had a huge air bubble that continiously popped and rose.

Marshay, age 10 of Washington, DC wrote:
When I created the expirement we set it on the table and watched it bubble. It was foamy and looked like coffee. It STINKS!

Geraldine, age 10 of Washington, DC wrote:
When I did the expirment I saw bubbles exploding and it was lumpy. It would rise adn then come back down.

Maia, age 10 of Washington, DC wrote:
When I did the expirment the yeasted puffed up, and stinks!

Destinee, age 10 of Washington, DC wrote:
The yeast was brown and stinky. The yeast was blowing up CO2. It was giving out gas bubbles.

Guy, age 11 of Washington, DC wrote:
The yeast smelled like spoiled milk. I heard popping. I saw popping bubbles and teh bubbles had holes in them. It was rising and popping. It gave out gas bubbles that stink! It was bumppiest.

Paul, age 11 of Washington, DC wrote:
When the CO2 from the yeast caused the yeast to form a bigger bubbles and CO2 inside of the bubbles.

Ty'Ji, age 11 of Washington, DC wrote:
It started to bubble and foam. It was a nasty color and it looked nasty. It was crackling and it smelled like spoiled milk. The yeast was going up and down.

Zachary, age 11 of Lebanon, OH wrote:
When I did this experiment I put a rubber balloon over top of it and the balloon actually blew up because of the carbon dioxide. It was rad!!! I suggest you try this to.

Rachel, age 12 of Sweden, KY wrote:
that was amazing!!! this project is so cool! just like a volcano

Amanda, age 12 of Los Angeles, CA wrote:
that was awesome. I won the science fair. I looks cool with food coloring

Dionne, age 10 of New York, NY wrote:
when I did all te ingredients it started fulling up I got scared because I thought it was it was going to explode byt it didint

Miley, age 11 of NY wrote:
It blew up like a volcano. But cooler. Now I know what caused it to blow up.

Erik, age 8 of Minneapolis, MN wrote:
We tried honey instead of sugar and it did bubble but it didn't overflow.

Andelica, age 13 of Co. Springs, CO wrote:
the yeast filled outthe cup and that all I know

Jessica, age 11 of Silver Spring, MD wrote:
I really liked this expreiment!! But I kinda did this at school and it was more fun. We put it in a bottle and covered the hole with a balloon. In like 5 min, the balloon was all filled up!!

Dilly, age 12 of Jackson, MS wrote:
It was just like you said it would be, of corse!.

Jeremy, age 10 of Honolulu, HI wrote:
I got a really cool idea to do it for a vocano project. put the yeast than put a bunch of water, food coloring and for quick results, put in vert hot water, or lots of sugar, or both. That worked for me

Abbey, age 11 of Ogden, UT wrote:
Its ALIVE!!! It was just way cool to see... how it like bubbles and grows and shrinks!!!

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