Our last class on weather was about wild weather: hurricanes and tornadoes. So fun to study - especially since Maryland rarely sees either!
I started with 3 containers. One was completely filled with rice, representing the molecules in a solid - when you shook it, not much happened. One was half full of coarse sugar - when you shook it, it flowed around the container like a liquid. The last was empty except for a few metal marbles. When you shook that (plastic) container, the marbles went all over and crashed into each other.
The idea was that heat adds energy and makes the molecules move faster, causing them to bounce off each other and expand.
We went on to fill a plastic water bottle with steam from the kettle. The bottle expanded and then we capped it and put it in the freezer. The bottle shriveled up as the gasses cooled and shrank - very satisfying for the kids to watch, especially when we opened it up and heard the "hiss" of more air entering the bottle.
While I was at it, I mentioned the thing that expands when you cool it far enough: water! We filled a glass jar, capped it tightly and put it (in a ziplock bag) in the freezer. We will see what happened on Friday!
The idea that ice floats is so fascinating to me. I really see it as evidence of God's care for the world. If you think about it, life on Earth could not exist if water didn't expand when it froze. If ice sank, you could not have life in the oceans and all the deep currents that keep our weather going would stop. If the ice was at the bottom, since cold tends to fall, it could never melt, the seas would just fill up with ice.
Anyway, we talked about the difference between tornadoes (small but the most intense storm on Earth) and hurricanes (vast, fueled by energy in the water).
We talked about the hot air rising and cold air falling at the same time. What happens when a bunch of people want to go up the stairs at the same time a bunch of people want to go down the stairs? (chaos, mostly, in my experience!) What happens when you let water go down the drain in the bathtub? God has a better answer! The water spins going down and that opens a tunnel in the center for the air to come up. That's what happens in tornadoes and hurricanes as well, although I'm not sure it would work for people and stairs.
So, of course, we had to make the tornado in a bottle! We actually have a connector for this experiment, but I couldn't find it, so we used duct tape (and a mop for the spills..). You fill a soda bottle half full of water (we added color and glitter for fun), stick another bottle on top and tape them together with duct tape.
I have to admit, having four Zoomlian lab assistants is great! There are only six or so kids (Oob comes and goes) in the class, as well as a mom or two hanging out, and with that much help you can do just about anything, even with kids as young as Oob. Thank you, Zoomlians!!
Next week we are skipping, but we will pick up again the following week with volcanoes and plate tectonics!