Junior+Science+-+Bouncing+Eggs

=A Bouncing Egg= It's easy to make a rubber egg and the chemistry of removing the the eggshell with vinegar is interesting. What you're left with is a totally embarrassed naked egg and a cool piece of science! Here goes..... || Place your egg in the jar. Cover it with white vinegar. || Screw on the lid. Leave your egg alone for 4 days. || What are all those bubbles...? || The naked egg - rubbery, swollen and ready to bounce! || ==What's happening...== The egg shell is made of calcium carbonate - so are your bones. Calcium makes them strong. The white vinegar is an acid. It dissolves the calcium in the egg shell. What's left? Carbon dioxide! So those tiny bubbles are full of carbon dioxide gas.
 * ==What you need.....==
 * [[image:P1200014.JPG width="351" height="262"]]
 * [[image:P1200211-1.JPG width="352" height="256"]]

Underneath the shell is a tough, rubbery membrane. This isn't dissolved by the vinegar - that's why the egg yolk and white don't spill out when the shell dissolves. The membrane isn't quite waterproof so some of the vinegar seeps through it, into the egg. That's why the egg gets bigger. || You will know when the egg is ready - there is no more shell to dissolve, so there are no more carbon dioxide bubbles. Empty the vinegar and replace it with water. Your egg is ready to bounce... || Our expectations were high! We made a 5cm graduated scale up a science stand. At 5cm the eggs bounced safely. At 10cm they went....
 * [[image:P1200245-1.JPG]]

|| This time, **blow the egg** and put the empty shell in the vinegar. Leave it for about 10 days.......
 * =A Folding Egg....=

The shell dissolves and leaves the membrane. Gently squeeze the fluid out of the membrane. You can blow it up by **gently** blowing air into it through the blow-holes you made at the start.**It looks like a real egg!** Cover the top of the glass with your hand and shake the glass. Air will slowly work it's way into the egg and //**Abracadabra...**// the egg will magically restore itself.
 * Gently** squeeze it again. Drop the egg in a tall, clear glass.

Try to get some of the powder inside the egg as well. The powder will help keep the egg membrane from drying out and cracking - and it makes the egg look even more real. The egg membrane ready for folding....
 * Hint:** Dust the egg membrane with some talcum powder.
 * This magic trick is over 100 years old!** || [[image:folding_egg.jpg width="333" height="333"]]

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