The question: Will an orange sink or float?
We polled this question with a simple yes or no for the question of the day. Only two children out of the class said that the orange would float.
Those two were right! With the peel of the orange intact the orange did indeed float.
Our question then became: How can we sink the orange?
After several interesting suggestions (hold it down, add weights, etc...) one of the children said we should peel it. We then put it back in the water minus the peel and low and behold it sunk!
We then tried cutting an orange in half to see if it would sink or float. Some of the children thought that the insides of the orange would absorb the water like a sponge and pull it to the bottom but once again the orange floated on the water.
Here is why: The peel or rind of the orange has hundreds of tiny holes that collect air. These air pockets in the rind act like a life preserver for the orange which help to keep it afloat. Without the rind the orange is heavier than water and instantly sinks to the bottom of the bowl.
Click here for another fun STEM experiment.