Orange Float or Sink?

Here’s a simple snack time experiment!  All you need is water, a glass and a Clementine (or Cuties, as my kiddos call them).  Takes only a few minutes.

Here’s what you need to get started:

• small oranges like mandarins or clementines
• Tall glass with water

Ask your kids to predict what they think will happen when you place the orange in the water.

Add the orange to the water and observe.  Were their predictions correct?

Peel the orange.  Now predict what will happen when you place the unpeeled orange into the water.

Add the unpeeled orange to the water and observe.  Were their predictions correct?  Ask them why the orange behaved differently with and without the peel.

From these results, the boys wanted to know if it was just the peel that floated, so we tested that as well.

The peels floated at the top as well.  What’s going on? We discussed the differences between the peel and the orange.  Is there air inside the orange?  What is special about the peel that it floats and also causes the entire orange to float?  Since the boys and I have done several floating and sinking experiments together, they immediately suggested that air and density had something to do with our observations.

This was a great investigation on floating and sinking using oranges and a great snack time “quickie” science experiment!

The Science behind the Activity:

Oranges contain quite a bit of air inside them which causes the overall density of the orange to be less than that of water, so it floats.  Also, the peel keeps the water from getting inside the orange.  Once the peel is removed, water can enter through the membranes of the orange slices and will cause the orange to increase in density and sink.

For a more complicated explanation involving buoyancy and Archimedes’ Principle (a concept that is more challenging for most toddlers and preschoolers to understand) please visit the link where I got my idea from: http://www.playdoughtoplato.com/orange-buoyancy-science-experiment/