FERMENTATION

Year 8's have been learning about chemical changes. They applied their understanding through a practical investigation on fermentation. Here is what the students had to say:

To make the results more accurate, I would reduce the grams of yeast added because the results showed that the fermentation process was ruined because the extra 2 grams of yeast made much more gas, and this forced the liquid out. Cooper 8.4

The data showed that my hypothesis was correct because; including more sugar in the experiment did create more CO2/ Carbon Dioxide gas. My hypothesis was correct and reliable because it was a simplistic and easy way of describing what occurred during the experiment. Layla 8.4

The experiment was mixed with physical and chemical changes. When the water and sugar were mixed, it didn't create a new substance and could have been reversed. When adding the yeast to the sugar water it created a chemical change. The process created a new substance, and it couldn't be reversed. After the yeast was added to the sugar water, it started bubbling, showing signs of fermentation. Oscar 8.2

When the sugar was added to the water in the glass beaker and stirred, the sugar dissolved and did not form a new substance, it just changed it's appearance. A physical change is when it changes it's shape or appearance and the change can often be reversed. Isaac and Lucas 8.4

One part of this experiment involving a physical change was when we dissolved the sugar into the warm water. Dissolving is a form of physical change, which doesn't create another substance. Another part of this experiment involving a physical change was when we boiled the water. This process didn't create a new substance, only increased the water's temperature, and changed it's state, as the heat evaporated some of the water into gas. Arielle 8.2

Martine Turnbull - Science Teacher