Messing around with liquids.

I haven’t posted about RSO Chemistry for a million years, have I? The lessons are usually so chaotic (with two seven-year-olds and a three-year-old participating) that I don’t have much breathing room. I have mixed feelings about the curriculum as a whole, but today’s lesson was awesome enough to inspire me to post.

We’re in the middle of a great unit on the states of matter. We started out with the basic early-elementary stuff about solids, liquids, and gases; we inspected ice, water, and steam and measured the boiling and freezing points of water. But then the curriculum had us trying to identify the state of mayonnaise. And Jell-O. (Or, in our case, vegan kosher Jell-O substitute.) Now we’re working on exploring the characteristics of solids, liquids, and gases in more detail.

Today we went outside and acted out relations between molecules in a solid, a liquid, and a gas. First, Alex and her friend B and Colin were molecules a solid. I put one of Colin’s simple jigsaw puzzles on the lawn and told the kids to solve it together. They huddled closely around the board and got to work. There was some shifting from side to side, but they didn’t change places in relation to each other and they didn’t move much. There was a lot of close interaction, though, as they jostled for pieces and cooperated to get the puzzle done.

Next, I had them spread out about ten feet apart from each other and handed them a frisbee to toss back and forth. As molecules in a liquid, they continued to have frequent interaction with each other, but from further apart, and with more and freer movement.

Finally, they were molecules in a gas. I told them to run in a random pattern around the lawn. They weren’t to try and catch or evade each other, but when they passed someone they should give a high five.

We all came back inside in excellent spirits. Because we focused on solids last week, the rest of today’s lesson focused on liquids. Last week, for example, we visualized what would happen if we hit the kitchen table with a hammer. This week, everyone collapsed in giggles as I led them through imagining and describing what would happen if we hit milk with a hammer.

“…And liquids have a definite volume, right? Could I pour Alex’s milk in a smaller glass if I just squashed the milk down really hard?” More giggles. They didn’t really need a demonstration to understand, but I decided it would be fun anyway. I put a shot glass on a deep dish and started pouring Alex’s milk into it, encouraging the kids to try squashing the milk down so more could fit. Hilarity ensued. We also did enough pouring back and forth between cup, shot glass, and dish to establish that liquids don’t have a definite shape.

“What about density? We figured out last week that all solids don’t have the same density – do all liquids?” Alex and B decided, after some discussion, that if you had the same amount of two different liquids they would have the same density.

We measured out a quarter-cup each of water, canola oil, and corn syrup. Studying them intently, the kids decided that corn syrup was denser, and that water was the least dense. Then I poured them very slowly and carefully into a single glass. Very impressive! The kids loved it. They drew beautiful pictures of the layered liquids on their lab sheets, and we finished up by Googling for pictures of pousse cafe cocktails.