What do mammals need to survive?

We have been investigating what all mammals need to survive. We learned that mammals need

• food
• air (oxygen)
• water
• a heat source

And all mammals convert the above into energy to fuel their bodies. After that fuel is used up, the mammal produces a waste product.

To prove that this was true, the children in Room 7 ran a science 'experiment'. Rather than experimenting on a live mammal, we used yeast, a living organism, instead.

We put Yeast in a small water bottle. We feed the yeast food (sugar), we gave the yeast air and water, and gave the yeast a heat source (the radiator).  We then put a balloon over the neck of the water bottle.

This is what we saw happen:

What was filling the balloons?

We concluded it was the waste product from the yeast, as it converted the food, water, air and heat into energy. The waste product was carbon dioxide, and it smelled like bread!