Floating and Sinking

Today we looked at what sinks and floats. First we made predictions and then went and tested our ideas. It was interesting how many things we thought would float actually sank!

Item	Floats	Sinks
Wooden Block	☺
Paper Clip		☺
Plastic Cotton Reel	☺
Rubber band		☺
Crayon		☺
Wooden Rod	☺
Marble		☺
Rock		☺

After this, Mrs Brieseman asked us what we thought would happen to an Orange and a Mandarin - would they float or sink. We thought they would sink but they floated!  The mandarin sank though once it was peeled. 

The rind of the orange is full of little air pockets that actually lower the density of the orange and make it float on the water. When this was removed (no more air pockets) meant that it had a greater density making it sink.

Orange skin magnified under an eye viewer