Sunday, January 8, 2012

Floating Eggs - Water Density Science Experiment

Today was a perfect day for science experiments. Rainy and cloudy outside, perfect time to make things interesting at home :)  Last time we made a cloud in a vase.

Today we made eggs float in water... we had eggs on the surface, all the way at the bottom and also floating in the middle!! How you ask?!  MAGIC!!

floating eggs science experiment

What you'll need?
3 eggs
3 glasses
Water
12 tbsp of salt

The idea is that an egg will float in denser water.  Adding salt increases water density and makes the egg float.

Emma is not even four years old, so I started by talking about the sea and the salty water we swim in, how she easily floated in it, more so than in a swimming pool.

We filled up two glasses with water and the third glass we half filled with water.  Emma then added 6 spoons of salt to the half filled glass and 6 spoons to one of the full glasses.  Stir in the salt.

floating eggs science experiment

I asked Emma what she thought would happen next, if the salty water was like the water in the sea and the drinking water was like the water in the pool.  We carefully dropped eggs into the two full glasses, one with salt water and one with tap water, to see what would happen. 


As you can see, the egg in the salty water floated to the top and the egg in the tap water dropped to the bottom. 

And now, for the fun part! How did we get the third egg to float in the middle of the glass?

Once the salt has settled to the bottom of the glass, slowly and carefully add tap water to the glass half filled with salty water.  This way the salty water and the tap water will not mix. 

Carefully drop the egg in the glass.  It should fall through the drinking water until it reaches the salty water, at which point the denser water would be enough for the egg to float, magically, in the middle of the glass! 

Emma loved this experiment, I hope you will too :)

  
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1 comment:

  1. I love this experiment! Will try it with Maya tomorrow! :)

    ReplyDelete

 
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