Can I discover that yeast is a micro-organism that produces gas?
First we poured 200ml of water into 6 plastic cups and added yeast to each cup. We then weighed out 20g of salt, sugar, rice, coffee, flour and oil. We added each ingredient to a cup of the water and yeast mixture. We poured the mixtures into 6 ziplock bags and left them for two hours to see which ingredient would react with the yeast the most. We found that the micro-organisms in the yeast got the most energy from the sugar to produce the most gas. The bag exploded! The salt reacted the least.
As part of our Chinese Inventions topic we made our own water clock. We taped two clear plastic cups together and made a hole in the bottom side of the top cup. We placed a cup under the hole to catch the water. We then poured some water into the top cup and timed for two minutes. After two minutes, we blocked the hole so no more water could pass through. We marked the side of the cup which was collecting the water to show the level after two minutes. We did it again to check that it made the same level again after two minutes.