We had a lesson on bats at our Tuesday co-op. After talking about how many insects a bat can eat every night, we all agreed that we like bats.
Bats have an excellent sense of smell, and bat mothers use their noses to find their own babies in the "bat nursery" after a night out hunting.
We did an experiment to demonstrate sort of how that would work. We gave each kid a cotton ball with a certain scent on it (vanilla, lotion, acetone, etc.) There was a matching scented cotton ball in the center of the table, and the kids had to find the match to their "baby" by using their noses.
Some of those babies didn't smell so good!
With only 10 distinct smells, it was still pretty tricky for our non-bat noses to find the matches.
The kids played a couple games to learn about echolocation. The first was Marco Polo except the kid with the blindfold was the bat and had to say "beep" while the other kids were bugs and had to say "buzz."
Then they did a little experiment to show how sound can bounce off of an object and come back.
To solidify the concept that bats are nocturnal, the kids played red light/green light with a twist. The caller said, "Nighttime!" for go and "Daytime!" for stop.
On a sheet of plain newsprint paper, each kid measured the wingspan of a different bat, including the smallest and largest bats in the world.
Finally, we talked about bats living in caves and how caves are formed. Each child was given a piece of clay and a few sugar cubes. They flattened the clay and wrapped it around the sugar cubes, leaving a small area of the sugar cubes exposed. Then the clay was dropped into a bowl of water where the sugar dissolved, leaving a little clay cave.