Spinning eggs and hot air: Senior Infants

Teacher had some eggs with her at school today.  Some of them were raw, but some were cooked.  Teacher showed us how to tell which egg is raw and which is cooked.  When you spin a raw egg and then put your hand gently on it and ask it to stop, it won't stop, it just keeps on spinning.  This is because the inside of the raw egg is a liquid, and even though the shell stops spinning, the inside keeps on spinning (like a child in a car, without a seatbelt, will keep travelling forward when the car comes to a sudden stop).
With the cooked egg, when you spin it, put your hand gently on top and ask it to stop, it does.  This is because the inside of the egg is solid and stuck to the shell.  When the shell stops moving so does the inside of the egg (like a child with a seatbelt on will stop moving when the car stops moving too).

The next experiment we tried was to try and get a boiled egg into a bottle.  This is done by heating the air in the bottle (either by lighting a candle and dropping it in the bottle, or by putting the bottle into hot water).  Then we put a boiled egg on top.  The egg just sat there, until the air in the bottle cooled and got smaller (we helped this along by putting the bottle into cold water).  When the air in the bottle cooled down the boiled egg got sucked in.  The egg only went a little way into the bottle before getting stuck.  Then the pull on the egg was so strong that the white of the boiled egg split and we could see the yolk.  This all happened without any of us touching it at all.  Teacher hoped that the egg would go all the way into the bottle, but it didn't.  We think this is because the egg was too big.  We will try and do this experiment again when we have a smaller egg. 

Another interesting experiment we tried, is to see what happens to a glove on a bottle when the bottle is put in hot water.  When the glove wa put on the bottle it was very floppy.  When teacher put the bottle into a can of very hot water, the air in the bottle expanded and the glove inflated.  When the teacher took the bottle out of the hot water, the air cooled and the glove went floppy again.  It is very interesting to see what happens when air is heated and expands, or is cooled and constricts.