demonstrations:floating_egg
Floating Egg
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Density and Buoyancy, Food Science and Nutrition
Alternative titles: Egg Density Experiment
Summary
This experiment demonstrates how adding salt to water changes its density. A raw egg sinks in plain water but floats in saltwater because the denser solution supports the egg.
Procedure
- Fill a tall drinking glass about three-quarters full of plain water.
- Carefully place a raw egg into the water and observe that it sinks.
- Stir in about three tablespoons of salt, the egg should rise as the density of the water increases.
Links
Floating Egg Experiment | Why Eggs Float in Salt Water | The Egg and Salt Experiment - Hungry SciANNtist:
📄 Floating Egg - Science Fun For Everyone: https://www.sciencefun.org/kidszone/experiments/floating-egg/
Variations
- Try floating other foods, like potato or carrot slices, by adjusting the amount of salt added.
- Record how much salt is needed to make different objects float in a data table.
- Test with sugar instead of salt and compare the results.
Safety Precautions
- Handle glassware carefully to avoid breakage.
- Clean up any spills immediately to prevent slippery floors.
- Wash hands after handling raw eggs to avoid risk of bacteria.
Questions to Consider
- Why does the egg sink in tap water but float in saltwater? (Because the density of saltwater is higher than the density of the egg, which allows it to float.)
- What would happen if you added only a small amount of salt? (The egg might sink more slowly or remain suspended partway in the glass.)
- Could you make the egg float in the middle of the glass instead of on the surface? (Yes, by carefully adjusting the amount of salt until the water’s density matches the egg’s density.)
- Why is salt able to increase the density of water? (Because adding salt increases the mass without greatly increasing the volume, raising the density.)