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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

Ethan, age 10 of West Warwick, RI wrote:
I saw that it was all bubbly and foamy It was really cool!

Katherine, age 16 of Orlando, FL wrote:
the hot and warm water tied when I tried it the cold water didn`t do anything

Liz, age 11 of Oxford, England wrote:
We did it at school and we had 2 cups, one with sugar and one without. The cup (we did it in cups) with sugar in it bubbled up really quickly and overflowed, but the one without sugar didn't do much.

Mackenzie, age 13 of Abilene, TX wrote:
When I mixed it up in my kitchen, turned the timer for 10 minutes, and it already started bubbling. I observed it in those 10 minutes and I couldv'e sworn it started moving, but, I had it in my hand!

Nicole, age 14 of Oregon City, OR wrote:
I put the yeast in with the water and sugar and the bowl started over flowing with bubbles lol its was kinda cool to watchh

Chloe, age 9 of Raymore, MO wrote:
I set the timer for 35 mins and the bag looked like if I let it set for 5 for mins it would EXPLODE! It looks like it's bread dough. It smells like yeasty BAD!

Anna, age 10 of San Diego, CA wrote:
It got puffy and foamy also had bubbles. It went back and forth in my little plastic bag. The bag looked like it was about to explode!

Amatullah, age 11 of Elizabeth wrote:
what happend was that when sometimes when you pour peroxide it rises so much that it can overflow the whole bowl I was laughing so much when it happend

Josh, age 7 of Santa Clara, CA wrote:
Mixed yeast with sugar and warm water and put a balloon over the bottle. The balloon slowly popped-up.

Alyssa, age 10 of Oromocto West, NB wrote:
at first I thouught it stunk. I do not like the smell but toward the end it worked verry well.

Meryn and Selma, age 10 of Newcastle wrote:
it fizzed up.

Shayna, age 10 of Chicago, IL wrote:
It bubbled up and made a huge mess.

Stephanie, age 10 of Amherst, MA wrote:
it bubbled up and it made my house smell bad.

Stephanie, age 11 of Bronx, NY wrote:
Wow. This is amazing. I am doing it for my school project, it starts to bubble and me and my mom made it in bread together!

Shaniya, age 8 of Manning wrote:
it fizzied up.

Maryum, age 12 of Peshawar, Pakistan wrote:
I performed it in the classroom. Everybody was amazed at that thing.

Cris, age 9 of Hong Kong wrote:
It stinked in my class room

Miguel, age 12 of New Jersey wrote:
I did it in school but with beaker and ballons in the beaker so the ballon would fill up with carbon dioxide

Jasmine, age 12 of Cotton Valley wrote:
the yeast came up

Doyle, age 5 of PA wrote:
we did this in my homeschool and we added colored sand to it and not only did it grow, but also absorbed the sand so some of the particles of yeast were blue and my sister's yeast was pink it was very cool.

Simon, age 10 wrote:
It was kind of dissapointing. We put sugar and yeast in warm water, but after like 20 minutes, you could see very tiny bubbles. It STINKS!

Courtney, age 11 wrote:
Nothing happened at first but then I added more water and sugar.

Erin, age 11 of Mount Horeb, WI wrote:
nothing happened at first but then we added more hot water and yeast and sugar. The top turned white but that was about all.

Sofie, age 13 of Temecula, CA wrote:
It was sooo cool we did it at my school and I thought it was weard but I liked working on making the yeast into cooking bread WHO NEW THIS WAS SUCH A COOL SCIENCE PROJECT!

Travis, age 12 of Honolulu, HI wrote:
it was a very good experiment,

Anissa, age 13 of New York, NY wrote:
We put hot water and a little extra sugar and it over flowed at 8 minutes. IT WAS SSSSSSOOOOOOOOOO cool!!! I REALLY REllly like this experiment!!! I think I am gonnado it again it was so fun im gonna even ask my teacher if we can do this experiment!!!

Hamilton, age 10 of Honolulu, HI wrote:
I have a question about the experiment do I stir it together or just put it in the bowl and wait?

Ms. O's Class of Washington, DC wrote:
after a while, the yeast was fluffy from the bubbles. The co2 made the mixture fluffy.

Jeni, age 12 of TX wrote:
it just fizzed, then I gave a little to my dog she loved it!!

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