Science Sunday--Is yeast alive??

Our science question of the day was: Is yeast alive?

We started by looking at a teaspoon of dry yeast in our hands. It was very dry and tiny and Luke thought it looked like grains of sand.

It didn't look alive.

We put our yeast onto black construction paper and mixed in 1 teaspoon of sugar. It really didn't do much, although some of the kids thought they could see it chewing on the sugar.....that didn't appear to be true when we looked with a magnifying glass.

Our yeast still didn't appear to be alive.

Something that is alive eats and breathes and grows....our yeast wasn't doing that.

We then put a teaspoon of yeast, a teaspoon sugar and 1/4 cup of lukewarm water into a ziploc bag. Seal the bag and place in a sunny spot.
Something begins to happen. The yeast begins to grow---a sign of life. It gives off CO2 gas (it is burping)....that is breathing. It is also what make bread fluffy.
In another ziploc bag we placed just yeast and warm water....it gave off a little CO2 but then stopped. We learned that yeast needs to eat. Our yeast was eating the sugar we had added to the bag.
The kids were very impressed by the changes they were seeing.....our yeast was alive.
Kimmy decided to keep her bag of active yeast as a pet. She carried it around for quite a while.
Yeast, growing under the magnifying glass.

We opened a bag. What did the smell remind us of?? All the kids agreed, our yeast smelled like bread. We learned that bread needs yeast to become fluffy and delicious.

So that is exactly what we did...we made fresh homemade bread!

The little air pockets in the bread were made from the living yeast.

A perfect science experiment for a cold, snowy day!