The Secret of the Floating Mandarin: Can a peel make a difference?

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Density is a fun and pretty easy concept to demonstrate to kids. Dunking objects into a glass of water and making a splash? Yes, please!

The Floating Mandarin experiment showcases density through its peel. The peel has a lot of tiny air pockets, and when attached to the fruit, allows it to float. This experiment demonstrates density and buoyancy.

Let’s get to the experiment!

How to make the Floating Mandarin Density experiment

Supplies you will need

For this experiment, you’ll need:

  • Mandarin oranges (2)
  • Glass of water (2)
Supplies needed for the Floating Mandarin Density experiment

Before you start

This experiment could make a splash, so we put a towel down below the glasses of water.


Here is how to do this experiment with your child:

Step 1: Fill two glasses of water to equal levels

Fill the two glasses of water to about 2/3 of the way full, to allow for water displacement.

Adding water to each glass
Two glasses filled to about 2/3 full

Step 2: Peel ONE mandarin

In this experiment, we are comparing a peeled mandarin to an unpeeled mandarin. Peel just one of the mandarins completely.

Removing peel from one of the mandarins

Step 3: Drop mandarins in the water

Ask your child which they believe will float and why. Drop the mandarins in their respective glasses and see if you are correct!

Dropping both mandarins in the glasses of water
The peeled mandarin sinks and the unpeeled mandarin floats

The STEM behind the Floating Mandarin Density experiment

This experiment teaches:

  • What is density?
  • Buoyancy
  • How parts of an object can affect its density

How it works

The experiment demonstrates how density affects whether an object floats or sinks.

The mandarin peel, with its air pockets, is less dense than water, allowing the mandarin to float. When peeled, the more dense fruit sinks.

What is density?

Density is a scientific property that tells you how much mass is packed into a certain volume.

Think of it as a measure of how tightly squeezed something is. A bowling ball, for example, has much more mass squeezed into its volume compared to a beach ball, even though they might seem similar in size. That’s because the bowling ball is denser; it has more concentrated in the same amount of space.

Density helps explain why objects behave differently in fluids and why some materials are better suited for certain purposes. For instance, a life jacket is made of a low-density material to help people stay buoyant in water.


Buoyancy is the ability of an object to float.

If an object’s average density is less than that of the surrounding fluid, it will float.

The reason is that the fluid (water, in our case) has a higher density than the object. Since it’s denser, it contains more mass and therefore more weight in the same volume. The buoyant force, which equals the weight of the fluid displaced, is therefore greater than the weight of the object.

In the case of our mandarins, the difference between the mandarin that sinks and the one that floats is the peel. Inside the peel, there are tiny air pockets that make the mandarin less dense than the water, so it floats. When we remove the peel and those tiny air pockets, the peeled mandarin becomes more dense than the water, and it sinks.

How parts of an object can affect its density

The experiment highlights how different parts of an object can influence its overall properties. The peel plays a significant role in its density because of the tiny air pockets in the peel. Remove that portion of the mandarin and that affects its density and ability to float!

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