Today we did some experiments with yeast from two of my favourite science books for kids
The first experiment was to see which environment yeast thrives. We added yeast and sugar to 4 containers and added cooled boiled water to three of them. We plastic wrapped the tops. One jar was wrapped in a towel. One was placed in a bowl of ice water, the third in a bowl of boiling water and the final waterless one just sat on the table.
We observed them every thirty minutes for 2 hours. T1 hypothesized that the warm one would activate and the lid would swell (correct), the ice bath one would stay the same (actually the plastic sunk downwards), the hot bath one would rise and then fall which it did - at 30 minutes the plastic was inflated but at 2 hours flat) and the dry one would do nothing (correct).
Our second experiment showed the effect of sugar on yeast. We put equal amounts of warm water in 2 bottles and added yeast. We then added sugar to only one bottle and covered the tops with plastic wrap. T1 was correct in his hypothesis that the bottle with sugar added would activate. It actually blew it's lid after about an hour and had bubbled over at the 30 minute mark.