Pressure

The best thing about 2013 for me personally was going to Hawaii and trying snorkeling for the first (but in no way the last) time. 

But, with my students, my favorite part of 2013 was a number of science explorations that we did with pressure. 

It started way back in December 2012, when we made popcorn the old fashioned way, in a popcorn popper, not a microwave. Unless they go the movies with any regularity, many young children no longer see popcorn popping because it comes from a bag in the microwave. 

We read Tomie de Paola's Popcorn Book. and found out that the reason popcorn pops is because there is a tiny bit of water in each kernel. When the kernel gets hot in the oil in the pan, the water pressure builds as the water expands and turns to steam in the heat. We used the word pressure to talk about the water pushing so hard on the outside of the kernel that eventually it popped it open. While we watched the popcorn, we could see steam coming out of the top vent of the popper...more evidence that Tomie was telling it to us straight. 

The next big pressure experience had to do with volcanoes (since I went to Hawaii). I brought back video from Hawaii of lava flowing in one of the vents on Kilauea. We were already talking about dinosaurs in the classroom, since it was a huge area of interest for the kids. We made a model volcano. First, I got a big plastic platter with a rim. I put a tall, skinny thick glass vase in the middle. We made home made play dough and built the mountain up around the tube. Last, we used modeling clay to make the outer layer, because it would not break down as quickly from repeated eruptions and lava flows. Then, just for fun, we put a bunch of plastic dinosaurs and trees at the base of the volcano.

Once the volcano was constructed, I put baking soda in the tube. Then the kids chose what color "lava" they wanted. We mixed food coloring and vinegar in a paper cup. If they chose a color that required mixing (like purple) we figured out which colors we had to mix. Then, each child in turn poured their cup of vinegar into the lava chamber and we watched the eruption. Most of the time the dinosaurs and trees got covered with lava.

Again, I was able to talk with them about how the middle of the earth is hot and, like the water in the popcorn, when the magma gets heated up, it gets pushed up by the pressure and causes the lava to come out of the volcano. 

In the spring, we carried out the Mentos and Diet Coke experiment. I was able to get a Mentos geyser apparatus that fits on top of a Diet Coke bottle. It allows you to pull out a pin to drop the Mentos into the bottle with a minimum of stickiness.  We learned that the reaction activates the carbonation in the Diet Coke. The gas builds up inside the bottle, putting pressure on the inside, and it pushes the soda up out of the top of the tube. We did this outside. Each time, we varied the number of Mentos that we loaded in to notice the difference in the height of the geyser.

The last pressure experience we had was making rockets. A parent of one of my former students is a amateur rocket builder. He helped all of the kids build their own rockets and we had an official "Launch Day" the second to last week of school. This way, we could, "blast off to kindergarten." In the classroom, we were talking about the night sky. The kids learned that the engine pushed hot air down with so much pressure that it pushed the rocket into the sky. 

The whole school came out to watch us blast 18 rockets into the sky. The middle school kids acted as the recovery team, going into the field where most of the rockets came down to bring them back to the preschoolers.