How to Make an Egg Float to Determine the Density

Float an egg in two glasses of water to determine if the egg is more or less dense than the water.

A popular experiment to test the density of water compared to that of an egg is the egg floating test. This is done by floating an egg in fresh water and salt water to see if the egg floats. If an egg floats in water, this means that the density of the egg is less than that of the water. If the egg sinks, this means that the density of the egg is greater than that of the water.

Things You'll Need

• 2 tall clear drinking glasses
• 1 cup of salt
• 1 carton of eggs
• 2 spoons
• Tap water
• Colored construction paper

Instructions

1. Remove the egg carton from the refrigerator and allow the eggs to sit at room temperature for about half an hour.

2. Fill one of the glasses half full of tap water.

3. Add 10 large spoonfuls of salt to the water and stir until the salt is dissolved.

4. Fill the other glass half full of tap water. Place this glass on a colored sheet of construction paper so you know which glass is unsalted.

5. Using the unused spoon, lower one egg into each glass one at a time. Be careful not to crack the egg in the process.

6. Observe the eggs. The egg in the unsalted water glass will sink because the egg has a higher density than the water. The egg in the salted water will float because the salt adds density to the water, making the water more dense than the egg.

References

• Science Buddies: How Salty Does the Sea Have to Be for an Egg to Float?
• Tech Links for CTCs: Floating Eggs

Resources

• Reeko's Mad Scientist Lab: Floating Eggs in Salt Water