| MadSci Network: Zoology |
Greetings Priyanca,
The following science experiment will demonstrate just why and how
the chicken is able to sit on the egg without breaking it.
I have also included some other neat experiments with eggs
that you can show your friends.
EGG SCIENCE
GOAL: To demonstrate the strength of eggs
MATERIALS
4 chicken eggs of equal size
1 egg carton
Hardback books of equal size and weight, at
least a 2-foot stack
No scientist of any age can resist this activity. A
vivid illustration of just how strong an egg really
is, Egg Science invites us to see how many
books can be stacked on top of four eggs. As
my kids' initial estimates were passed, they
squealed and gasped and called out the count as
each book was added and the stack grew taller
and taller.
Place four eggs of equal size in the second and
fifth rows of an open egg carton, pointed ends
down. Carefully place one book (with a surface
that is easily wiped clean) directly over the
eggs, and continue adding books, one at a time,
balancing the pile as you go. Try to see how tall
a tower you can make. As the museum explains
it, an egg's shape--two dome shapes pushed
together--makes it resistant to compression (in
other words, a force pressing inward). That's
why a mother bird can sit on her eggs without
breaking them. On the other hand, eggs and
other dome shapes are weak in tension, a force
pressing outward, so that a baby bird can easily
peck its way out when hatching. Of course, an
egg is easily broken from the outside if a strong
force is applied in one spot.
THE MAGIC TOUCH
Tell your friends you have "the magic touch" and can
"feel" the difference between an uncooked egg and a
hard-cooked egg without cracking them open.
1. To prepare for the trick, hard-cook an egg. Place it in a small pot, with
cold water to 2 cm (1 inch) above the egg, cover it with a lid, and heat until
the water boils. Remove the pot from the heat and let sit for 20 minutes then
rinse the egg under cold water right away. This will prevent a greyish ring from
forming around the yolk. Now you're ready for the trick.
2. With a friend watching, hold the hard-cooked egg in one hand and the
uncooked egg in the other and pretend to feel the eggs. (This won't tell you
anything, but it will fool your friend.)
3. Spin the eggs on a table top with a flick of your fingers. The egg that
spins best is the hard-cooked egg.
How the trick works: The yolk and white in an uncooked egg slosh around
slightly so that it wobbles instead of spinning. The hard-cooked egg always
spins smoothly.
NOW IT SINKS, NOW IT FLOATS
Put an egg in a glass of water and it will go towards the bottom.
But you can make an egg float right up at the surface and surprise
a friend - with a bit of kitchen magic.
You'll need: two glasses that are the same, about
1/4 cup (50 mL) salt, an uncooked egg.
1. Fill two glasses with water. Stir the salt into one glass until it is all
dissolved. Hide this glass nearby.
2. Ask a friend to put an uncooked egg into the glass of plain water.
3. Now tell your friend to close his or her eyes and repeat the command "float"
ten times.
This should give you enough time to switch glasses and put the egg in the
saltwater.
How the trick works: When you add salt to the water you make it heavier, or
more dense, than the egg. So the egg floats. With a bit of experimenting, you
can add just enough salt to make the egg float halfway in the glass.
Hope this answers your question about the common egg.
June Wingert
Try the links in the MadSci Library for more information on Zoology.