Year 6

Butter in a Jar – 6P

During Term 1, Year 6 have been investigating how chemical changes can occur. We have discussed that some of these changes can be reversible. An example of a reversible change is freezing water to make ice and then letting the ice melt to become water. We have also investigated irreversible changes such as making a cake. Once the ingredients are mixed and cooked, they cannot be taken apart back into the original ingredients.

On Monday we made butter in a jar to see what would happen. Before the experiment, we thought like scientists and learnt the word hypothesis. The students had to hypothesise what would happen when we placed the cream in the jar. Some students suggested that we would need friction. Others said that something would happen with the fat inside the cream moving together to form clumps of fat. 

The students half filled a jar with thickened cream and the students passed the jar around shaking it. After about two minutes, the cream had turned into whipped cream. A minute later it had changed consistency again and looked like parmesan cheese. After about five minutes the jar had a ball of butter inside and it was surrounded by a white liquid. We found out that this liquid was called buttermilk.

From the experiment we discovered that when the cream was shaken, the solids broke apart from the liquids and were attracted towards each other. The end result was a solid fat-based butter and a liquid (buttermilk) that had a low amount of fat in it. 

We discovered that this chemical change was irreversible, and we got to eat some afternoon tea.