Week 4: Eggs (Click here for supplies and activities list) Source: Steve Spangler Science Web Site 1. Hard-boiled or Raw?
Experiment
2. The Floating Egg
How it works 3. Egg in a bottle
How it works: The burning piece of paper heats the molecules of air in the bottle and causes the molecules to move far away from each other. Some of the heated molecules actually escape out past the egg that is resting on the mouth of the bottle (that’s why the egg wiggles on top of the bottle). When the flame goes out, the molecules of air in the bottle cool down and move closer together. This is what scientists refer to as a “partial vacuum “. Normally the air outside the bottle would come rushing in to fill the bottle. However, the egg is in the way! The “push” or pressure of the air molecules outside the bottle is so great that it literally pushes the egg into the bottle. | Fun Egg Facts: Bored? Need something to keep your mind busy on a long trip? Try to answer the following question: What came first, the chicken or the egg? Some other interesting questions to contemplate... Does the
chicken's body make the shell and fill it with the white and yolk
somehow, or does it make the white and yolk and then somehow wrap the
shell around it? How can an egg carton claim that the contained eggs have less fat and more vitamin E? Why do eggs turn hard when you boil them? How would you get the egg from the third experiment out of the bottle? Turn the bottle upside-down, making sure you don't drop the matches on your face. Put the bottle over your head and your mouth about half an inch from the mouth of the bottle. Blow into the bottle hard, and don't stop. The egg should come out.
This works because the air you blow in builds pressure behind the egg.
It pushes the egg right back out again You can also heat the bottle under warm water. The pressure of the air will push the egg out of the bottle. Another idea would be to add about an inch of water and break up an
alka seltzer tablet. Put the tablet in the bottle then turn the bottle
upside down. The pressure from the expanding gas should blow the egg
out of the bottle. |
Materials
- Cardboard tube
- Pie pan
- Raw eggs/or practice ball
- Water
- A large drinking glass.
Experiment
- Fill the glass about three-quarters full with water and center the dinner plate on top of the glass.
- Place the cardboard tube on the plate, positioning it directly over the water.
- Carefully set the egg (or practice ball) on top of the cardboard tube.
- With your writing hand, smack the edge of the dinner plate horizontally. Make sure you follow-through. (Tennis, anyone?) It’s important that you use a pretty solid hit so plan on chasing the plate and tube.
- Your egg will plop nicely into the water. It’s even more fun to watch someone else try to drop the egg.
How it works
Credit
for this one has to go to Sir Isaac Newton and his First Law of Motion.
He said that since the egg is not moving while it sits on top of the
tube, that’s what it wants to do: not move. You applied enough force to
the plate to cause it to zip out from under the cardboard tube (there’s
not much friction against the container). The edge of the pie pan
hooked the bottom of the tube, which then sailed off with the plate.
Basically, you knocked the support out from under the egg. For a brief
nano-second or two, the egg didn’t move because it was already
stationary (not moving).
As mad scientists we call the the Wile E. Coyote Law of Gravity
But then, as usual, the force of gravity took
over and pulled the egg straight down toward the center of the Earth.
Also according to Mr. Newton’s First Law, once the egg was moving, it
didn’t want to stop. The container of water interrupted the egg’s fall,
providing a safe place for the egg to stop moving so you could recover
it unbroken. The gravity-pushed egg caused the water to splash out. Did
someone get wet?
You could test longer tubes, more or less
water, different liquids in the container, and heavier or lighter
falling objects. So much science and so much fun!
5. Naked Egg Experiment - we will not have time to do this one in class, but it is easy and fun to do at home.
Materials
- Raw egg (preferably one with a brown shell)
- Tall glass
- Vinegar
- Patience (1 week’s worth)
- Place the egg in a tall glass or jar and cover the egg with vinegar.
- Look closely at the egg. Do you see any bubbles forming on the shell? Leave the egg in the vinegar for a full 24 hours.
- It's time to change the vinegar on the second day. Carefully pour the old vinegar down the drain and cover the egg with fresh vinegar. Place the glass with the vinegar and egg in a safe place for a week, that's right, 7 days! Don't disturb the egg but pay close attention to the bubbles forming on the surface of the shell (or what's left).
- One
week later pour off the vinegar and carefully rinse the egg with water.
The egg looks translucent because the outside shell is gone! The only
thing that remains is the delicate membrane of the egg. You've
successfully made an egg without a shell. Okay, you didn't really make
the egg-- the chicken made the egg-- you just stripped away the
chemical that gives the egg its strength.
How it works
Let's
start with the bubbles you saw forming on the shell. The bubbles are
carbon dioxide gas. Vinegar is an acid called acetic acid - CH3COOH -
and white vinegar from the grocery store is usually about 5% solution.
Egg shells are made up of calcium carbonate. The vinegar reacts with
the calcium carbonate by breaking the chemical into its calcium and
carbonate parts (in simplest terms). The calcium part (free ions of
calcium float around in the solution) while the carbonate part reacts
to form the bubbles that you see. Some of the vinegar will also sneak
through the egg's membrane (permeate the membrane) and cause the egg to
get a little bigger. That's why the egg is even more delicate if you
handle it. If you shake the egg, you can see the yolk sloshing around
in the egg white. If the membrane breaks, the egg's insides will spill
out into the vinegar.
Some fun egg videos: