Experimenting with objects to determine what will float and what will sink in water is always fun and educational. As with any experiment, we like to make predictions about whether the object in question will rise to the top or sink to the bottom.
The floating and sinking orange experiment adds an interesting twist, because the heavier orange is the one that floats and the lighter orange is the one that sinks.
•Two Glasses or Containers (Note: They must be big enough to put an orange into)
Step 1 – Begin with two empty glasses or containers. (Note: They must be big enough to put an orange into)
Step 2 – Fill each container 3/4 of the way full with water.
Step 3 – Slowly and carefully place an orange in one of the containers. What happens to the orange? Does it float or does it sink?
Step 4 – Next, remove the peel from the second orange.
Step 5 – Slowly and carefully place the peeled orange in the second container. What happens to this orange? Does it float or sink?
How Does the Experiment Work?
An orange with a peel is heavier than an orange without a peel. So why does the orange with the peel (the heavier one) float and the orange without the peel (the lighter one) sink?
The orange with the peel floats because the peel is porous and filled with tiny air pockets. These pockets of air make the orange to be less dense than water and cause it to float. On the other hand, when you remove the peel from the orange, you are in fact making it lighter, but you are also removing those tiny air pockets. Therefore, the orange without the peel is more dense than water and it sinks.