Monday, April 7, 2014

Electric current, Conductors, and Insulators

After static electricity, we went on to current electricity. First we played a game where we showed how current flows (emphasizing the point that it isn't a thing that moves along, but energy--an impulse). Everyone held a stuffed animal and we pretended the animals were electrons. You were only allowed to hold one animal at a time, so when I introduced an extra stuffed animal into the system by handing it to one of the children, they had to hand off their other animal to make sure they still only had one. We passed the "current" along the line, and then talked about how if the energy goes down a line, it has to stop when it reaches the end. But if it goes around in a circle, it can keep flowing and flowing. We also showed how an insulator works---if you insert another person into the circle, and that person CAN hold more than one electron, then when the current gets passed to him, he just holds onto it and it stops. In our game, people who easily pass electrons along are conductors, and people that hold onto electrons (or don't accept new ones) are insulators.
Then we did a lab testing different materials for their heat-conductivity. (Idea from here.) We boiled water, then poured it into identical glass jars that were wrapped with various materials, and noted the starting temperature. We then measured the temperature of the water after 20 minutes to see how much heat was kept in by the wrapping. (Our wrapping materials were foil, bubble wrap, fleece [I put felt on the lab sheet, but I couldn't find my felt so we used fleece instead], cotton cloth, paper bag, wrapping paper, and water---the jar of water was in another, bigger, jar of water.)
Here is the Lab sheet I made for us; feel free to use it.
We had a lot of fun testing these things and even some surprises (the foil was a lot better insulator than we predicted---maybe because of the air trapped in its wrinkles? or its thinness?).

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...