Today we learnt all about microorganisms. Microorganisms are very tiny living things. They are so small that they cannot be seen by the naked eye; to see them requires a microscope. Microorganisms live on and in our bodies, in the air, in water and on objects around us.
Yeast is a microorganism that is added to bread to help make it rise. When mixed with sugar, yeast reacts by eating the sugar. During this process, a gas is released called carbon dioxide. The gas bubbles make tiny holes in the bread causing it to rise.
We did our own experiment involving yeast. We mixed sugar, yeast and water in a bottle and put a balloon over the top and we did this twice. One bottle was placed in warm water and one was left at room temperature. Over the course of 40 minutes, the balloon in the warm bottle expanded to 26.5cm and the balloon in cold water expanded to 18.5cm.
