Eggs sink or float: Easy science activity for kids
Wondering if eggs sink or float? Try this easy science activity with your kids and learn about density while having fun!
This floating egg science experiment is a simple and fun way to explore density with your kids. Using just a few household items, you can show them how adding salt to water can change the way an egg behaves.
It’s an easy activity that doubles as a mini science lesson – perfect for curious young minds!
How does this floating egg experiment work?
The floating egg experiment is all about density. Density is how much “stuff” (or mass) is packed into a certain space (volume). An object will float if it’s less dense than the liquid it’s placed in, and it will sink if it’s denser.
When you first place an egg in plain tap water, it usually sinks because the egg is denser than the water. But when you add salt to the water, you increase the water’s density. This means the water becomes “heavier” compared to the egg.
If you add enough salt, the water’s density becomes greater than the egg’s, and the egg will float.
How to explain it to kids
Here’s a simple way for parents to explain it:
- “Think of it like this: the egg is trying to float, but the water isn’t strong enough to hold it up at first.”
- “When we add salt, it makes the water stronger – like giving it a superpower to hold up the egg!”
- “The more salt we add, the stronger the water becomes, and the egg will start to float!”
It’s a great way to teach kids about how some things can change if you add or take away something else – like turning plain water into salty water that’s better at holding up the egg.
What you’ll need
1. One raw egg
2. A clear glass or cup
3. Tap water
4. Salt
5. A spoon for stirring
Floating egg experiment instructions
1. Fill the glass or cup with tap water – about three-quarters full.
2. Gently place the egg in the water. Watch what happens!
3. Add salt to the water, one spoonful at a time, and stir well after each spoonful.
4. Keep adding salt and stirring until you see the egg start to float.
Fun variations to try
1. Use different liquids (like sugar water or fizzy water) to see if the egg floats or sinks.
2. Try fresh eggs and older eggs – do they behave the same?
3. Try warm water versus cold water and see if the egg sinks or floats differently.
4. Predict and record your results like real scientists!
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Authors
Ruairidh is the Digital Lead on MadeForMums. He works with a team of fantastically talented content creators and subject-matter experts on MadeForMums.