How to float egg in water? This is the science experiment we are doing today. We love easy kitchen science expriments that required no preparation. Today’s experiment just need salt, water and egg. It is very fun and easy. Kids as young as preschool age can do it on their own with adult guidance and supervision. From the activity, kids learn liquid density and buoyancy.
We get the idea from an app called Ubooly. We were bored at home, and took out Ubooly to find something to do. In the ocean science unit, there is this egg in salt water experiment.
Egg in Salt Water Experiment Materials
Everything you need can be easily found in your kitchen.
1. A glass that you can see through. To save water and salt, I suggest a glass that is not too big. As long as you can fit an egg into the glass, it should work.
2. Water. No special requirement, just tap water.
3. Salt. Again, just regular salt you use for cooking.
4. A raw egg.
5. A spoon. This is optional. If you child doesn’t want to touch the salt, you can offer a spoon for adding salt into the water.
Egg in Salt Water Experiment Steps
1. Fill the glass with water. Make sure it is not full. You wan to have space for egg too.
2. Add the raw egg into the glass gentally.
3. Take note where the egg is. Is it at the bottom of glass? or the middle floating in the water? or above the water?
4. Add salt into the water. Gentally stir the water to help the salt dissolve in the water. Keep adding salt into the glass till you start seeing the egg start to floating in the water. For us, it started to float up when we added about 4 spoons of salt.
5. Record your observation.
Egg Float in Salt Water Experiment Science Explanation
As amazing as it looks, the science behind the egg floating in salt water is quite simple. The density of salt water is greater than fresh water. But why?
What is density? Density is the amount of matter contained in a given space or volume. When there’s more amount of matter in a given space or volume, the object is considered denser.
Why do objects float or sink? An easy answer is an object sinks when its own density is greater than the medium’s density. In this egg salt water experiment, egg is the object, water and salt water are the medium. The egg is denser than fresh water, so it sinks in water without salt. By adding salt into the water, we increased the water’s density. Once the salt water’s density becomes greater than egg’s density, the egg starts to float.
Why salt water is denser than water? When salt is added and dissolved in water, it breaks down into ions that are attracted to the water molecules. This attraction causes them to bind, thus increases the amount of matter per volume (density). Instead of just having hydrogen and oxygen molecules in the water, sodium and chlorine in salt are also in the medium. This is why salt water is denser than tap water.
Next time when you are at the ocean beach, remember to ask kids why it is easier to float in ocean than to float in lake? They should be able to answer the question now that they’ve done this experiment.
Ubooly the educational toy is available on Amazon. Designed for kids age 4 to 10. Amazon link below leads to the toy.
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