Floating and Sinking

At school today we are learning about floating and sinking. What we did was put an orange in the water and then put a peeled orange in it. What happen was the the orange with the skin on floated and the peeled orange sank. It happen because of the density of the object and how much volume it has to store air. With the orange with the skin on had more  density and the skin was like an life jacket for the orange. With the orange without the skin on had the same density as the other orange put the water filled up where the air was. Therefore it sank.
I think the unpeeled orange had less density than the water. What do you think?