Eggs are an incredible adaptation that allow birds to stay light and able to fly while their babies are growing. Bird eggs are covered in a shell with lots of tiny holes. These allow air and moisture to pass through. Eggs are also covered in a coating that keeps out bacteria and dust.
Place the egg in your hand (take off any rings first). Squeeze the egg with even pressure. Does it break?
Now (over the sink or outdoors) squeeze the egg with just two fingers. Did it break?
What will happen:
The shape of an egg makes it very strong to even pressure. Even an adult squeezing it can’t break the shell.
When uneven pressure is put on the thin shell, the egg cracks easily.
When a bird sits on an egg to incubate it, the pressure is evenly distributed on the shell and the egg can easily support the bird. When a chick is ready to hatch, it pushes on just a small part of the shell with its egg tooth and the shell will crack to allow the bird to hatch.
A drinking glass
Place the egg in a glass and cover with household vinegar. Wait about 24 hours, pour the vinegar out and replace with fresh vinegar. Wait a full week and then take the egg out.
What will happen:
The shell is made of calcium carbonate, which dissolves in acetic acid. The vinegar will dissolve the shell, leaving the semipermeable membrane intact. The yolk and white will still be contained in the soft membrane, so it will look like an egg, but will be squishy when touched.
Are you a fan of Dog Man and Cat Kid? Dav Pilkey, the author and illustrator of these series, is presenting the virtual program, Flipgrid Virtual Field Trip: Cat Kid Comic Club is In Session: Create Comics with Dav Pilkey!, on Monday, March 22, 2021 from 12-12:30 p.m.
February’s STEAM at Home program featured Awesome Architecture and fun building activities. We learned that x-bracing (seen here on the John Hancock Center in Chicago) is one way that helps keep buildings straight and tall when wind blows on them. X-braces and shear walls collect wind forces and carry them to the foundation. Build your own braced tower at home with a few simple materials! Idea and images from Building Structures and Towers by Tammy Enz.
mini marshmallows (the book shows gumdrops, but we used marshmallows)
Break 4 noodles in half and make sure they are roughly the same length. Put marshmallows in the corners to connect them into 2 squares.
Break off about 1 inch from 4 more noodles and use these to connect your 2 squares. What happens when you push on the tower?
Add 2 noodles to one side make an X. Repeat on all 4 sides of your tower. Try pushing again. Now what happens?
As the marshmallows harden, your structure will get even stronger. What other structures can you build?