- cup or beaker
- raw, uncooked egg
1- Ask your child if an egg will float or sink. Carefully set the egg in a cup full of water. What happened? (It should sink! Eggs do have an air space inside that grows as the egg ages. A particularly old egg may actually float, but this is rare.)
2- Can you make it float? Add a tablespoon of salt and stir until it is dissolved. Try the experiment again. Continue adding a tablespoon of salt until your egg actually floats. The egg in the picture above only took two tablespoons.
What Happened? and Variations:
Adding salt changes the density of the water. The egg's density does not change. When the water is more dense than the egg, the egg will float.
Try the experiment with a boiled egg and/or other solutes (instead of salt). Do you see the same results if you use two eggs instead of one? What about brown eggs compared to white eggs? What else does your child want to test?
You can also display two cups, one with a floating egg and one with a sunken egg, and see if your children can spot the differences. Then see what they would like to experiment with!
I may share at any of these parties!