Friday, January 28, 2011

In Science Class . . . Week of 1/24

This week in science, we've continued our learning about how plants make energy (and gain mass) and how other organisms use that energy. We did an experiment with yeast. By giving the yeast sugar (in the form of crumbled up Chips Ahoy cookies), they became active and started cellular respiration. This process produces carbon dioxide as a waste product, which caused our bags of yeast and warm water to puff up! We used a tool to measure that gas produced as well as the amount of gas produced by the control experiment (no cookies), which was zero in most cases.
Key questions to ask your student:
  • What organisms make their own energy? How can we tell that they are making energy? (Gain mass, grow)
  • In the experiment with yeast, how did we know that the yeast were burning sugar? (They produced carbon dioxide as a waste product)
  • Can you think of other organisms that produce carbon dioxide as a waste product of cellular respiration? (Most animals, including humans!)

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