Collapsing Can Lab

Another lab we did was the collapsing can lab. In this lab, we had water in a soda can and we heated it over a burner. We waited until steam started to form and it pushed air out of the can. This took a while because it takes time for the molecules in the water to heat up and start moving around fast to form steam. Once we saw the steam rise, we immediately put it in a bowl of ice water. And when we did, the can collapsed. What really happend was that, like I said before, when we heated up the can, the molecules gradually started moving, forming steam and forcing air out of the can. The steam exerts the same air pressure in the can as it does outside of the can, balancing the air pressure. As the molecules move faster, the temperature of the water increases. We know that when water heats up, and it has reached its boiling point, the water molecules start to expand and steam begins to form. At this point, the water molecules are moving around at a high rate. Once we put the can in the ice water, the molecules experience a sudden temperature change, a sudden drop. They go from being hot to being really cold, from steam back into water really quickly. Now the air pressure inside the can is different from the air pressure outside of the can. When the molecules hit the water, they instantly stop moving fast and slow down. The molecules condense, and it is like a vacuum inside the can. There is no air pressure inside the can like there is outside of it. Now the can can't possibly resist the air pressure. This causes the can to finally collapse.

How Does Popcorn Pop?

To demonstrate radiation, we did a lab the other day. We microwaved popcorn! Interesting lab, isn't it? How can making popcorn be related to science? Well, as we all know microwaves produce heat. That's why we use it to heat up our food! Anyways, the heat transfers from warmer substances to cooler ones, like the popcorn kernels. When the kernels are heated, the molecules in the water that's in the kernels expand and move around, away from each other. This is kind of like a bunch of people put into a hot room. Because it's so hot, the people are going to move around, away from each other so that they don't get too hot. Now let's say that these people are super strong, like superman, and the room go hotter. What are they going to do? Run around, jump up and down, and hit the walls, over and over again until the room breaks and explodes. Likewise, the molecules in the water of the kernel are expanding and expanding. When there's no more room to expand, the kernels finally pop! Thus, creating wonderful, delicious popcorn. Isn't this very "scientificy-ish" ?