Science with Eggs

It is Science Week. We did a few interesting experiments in science week. We found out that eggs sink in water, but if you add salt to the water, the egg can now float.

We know why this happens......We did another experiment that is almost the same.....Put some rice into a cup and then put a bouncy ball in the cup, and fill the cup with rice (covering the ball). Now if you shake the cup the bouncy ball will always come to the top. This is because the little rice pieces are so small that they always race to the bottom of the cup first, so the ball always ends up on top. (That's why crumbs are always at the bottom of a cornflakes box!) The eggs are the same. The salt in the water always pushes to the bottom (because it makes the water dense) so the egg ends up on top. Interesting isn't it?

We did another experiment to find out if eggs are raw or cooked. We made both eggs spin and then we tried to stop them spinning. The boiled egg is very well behaved, it stops when it is told. (It's like wearing a seatbelt in the car). The raw eggs stops spinning for a second, but spins again as soon as you take your hand away (like someone without a seatbelt in the car, keeps moving forward even if the car stops in a crash). You can spin an egg to see if it is cooked or not.