Yesterday our pre-school room did an experiment using an orange. We wanted to see if the orange would float or sink. The children took it in turns to hold it, feel how heavy it was and make their guess as to what it would do. The majority of the children thought that it would sink and only a few thought it would float.

When we put it in the bowl of water the orange floated and the children were amazed! Some of the children tried poking the o...range in an attempt to get it to sink but it kept on floating. Then we peeled the orange and the children were asked again if it would sink or float. The majority said it would float as it had done so last time.

We put the orange in the water and it sank to the bottom of the bowl. The children were fascinated that it had sunk this time and they kept asking to try it again, but no matter how many times we tried it still sank!

The unpeeled orange floats because the rind is very porous and filled with tiny pockets of air. Even though you are removing mass when you peel the orange it is more dense and it sinks in the water.