Floating Egg Experiment

Stretched out on my back, the waves carried me up and down in the Florida sun.  I usually sink like a rock, but in the salty water there was no need for a raft as I floated along.  This simple floating egg experiment is perfect for explaining this phenomenon to kids.

Materials Needed to Float an Egg:

• 1 Raw Egg
• Tap Water
• Clear Container (big enough to float an egg)
• Table Salt
• Teaspoon

Time for your egg experiment!

Partially fill your container with water.  Hand your child the egg and ask them to predict whether the egg will float or sink.  Carefully place the egg in the water.  (It should sink; older eggs may float a bit.)

If your child has been to the ocean, this is the perfect time to discuss how much easier it is to float in the salty water.  Ask your child to predict how much salt you will need to add to the water to get the egg to float.

Now remove the egg from the tap water and stir in one teaspoon of salt.  Replace the egg and observe what happens.  If they egg still sinks, repeat the process.  (It took 3 teaspoons of salt to get our egg to float.)

Why does the egg float?

The egg sank in the fresh water and floated in the salt water because of density.  The more salt you add to the water, the more mass you add to it, making the salt water denser.  Because the salt water is saturated with salt particles it is better able to hold the egg up.

Extensions:

• Allow your child to experiment with different liquids.  Will the egg float in sugar water or seltzer water?
• What other objects can you get to float in the salt water?

I’m looking forward to the next time I can test out my floating abilities in the ocean.  Until then, this simple egg float experiment is a great way to introduce density to the kids.  

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