MAKE a BOUNCING EGG!When we think of eggs, we don't think of something that can bounce. Try this experiment and see what happens.
Materials: One egg, vinegar
Place the egg in a container of vinegar and leave it out on the counter for 36 hours.
What is happening?The
shell is dissolving! Vinegar contains acetic acid, which breaks apart
the solid calcium carbonate crystals that make up the eggshell into
their calcium and carbonate parts. Carbon dioxide gas makes the bubbles
that you see.
EGG-SpinMaterials: One hard-boiled egg, One raw egg, flat surface
1. Get both eggs spinning on the kitchen table.
2. Stop both eggs, then release them. Watch what happens.
3.
The hard-cooked egg will remain stationary, but the raw egg will start
spinning again. That’s because the liquid inside didn’t stop moving when
you stopped the shell. The moving liquid starts the shell moving again.
4.
Set the raw egg aside. Spin the hard-cooked egg again. Get it spinning
very, very fast. Once it’s going fast enough, the spinning egg will
spontaneously rise up on end and spin like a top.
5. If you don’t
get the egg to stand on end the first time, try again. To stand on end,
the egg must be spinning faster than about 10 revolutions per second.
It took us a few tries to get the egg spinning fast enough.
What’s Going On? The short answer is: Friction between the eggshell and the tabletop pushes the spinning egg up.
This
trick astounds people because the egg appears to be defying gravity.
Rather than lying down comfortably (as many of us prefer), the egg
spontaneously stands on end.
Some of the energy of the egg’s spin
(kinetic energy) is converted to potential energy, the energy that’s
stored in an object that has a distance to fall. When standing on end,
the egg has more potential energy and less kinetic energy—at least for a
few seconds.
EGG IN A BOTTLE (you will need an adult for this experiment)
Materials: one peeled, hard-boiled egg; a milk bottle or jar with a diameter just slightly smaller than the egg.
1. Cut a strip of paper approx. 2"x6"
2. Light the paper and place it inside the bottle.
3. As the paper smokes and burns out, set the egg on top of the bottle.
4. Observe what happens.
What's Happening?The
pressure of the air inside and outside of the bottle is the same, so
the only force that would cause the egg to enter the bottle is gravity.
Gravity isn't sufficient to pull the egg inside the bottle.
When
you change the temperature of the air inside the bottle, you change the
pressure of the air inside the bottle. If you have a constant volume of
air and heat it, the pressure of the air increases. If you cool the air,
the pressure decreases. If you can lower the pressure inside the bottle
enough, the air pressure outside the bottle will push the egg into the
container.
More of Miss Science and EGG-citing Science! Check out my first appearance on Arizona Midday. May 2010
Arizona Midday- EGG-citing Science 2010
