Friday, February 27, 2009

It's Electric!

This week my theme was Electricity. I have never taught Electricity before in preschool, so this was my beta test. Could I break the whole electricity thing down into concepts three and four year olds could grasp? Well, I was going to give it a try.

I had an electricity kit that I had received at my Steve Spangler Science in the Rockies conference last summer. The unit included a UFO ball, batteries, wires, single Christmas lights and a knife switch. Also included was a lot of information on how electricity does its thing.

To start, I decided to Google "electricity activities preschool". Not surprisingly, not a lot came up. All stuff regarding electricity is geared toward older kids. I did find a couple of cool examples of static electricity, so I decided I might want to figure out how to incorporate that too.

So, what do I want to get across to the kids? Hmmm...P=IV? No...How to measure amperage? No...How about just something as simple as why a light goes on and off. Ok, I started from there. I also wanted to talk about static electricity, and that would make a discussion of atoms necessary. Well? Why not? Using the Velcro Theory, I decided I would just toss a whole lot of information at them, and see how it went.

To introduce the topic, I asked the question, "What is electricity?" This stumped them, at first. Then a little boy pipes up, "Isn't what makes the lights go on?" "Yes! What else do you turn on?" And I got all kind of, computers, the Wii, my nightlight, the dishwasher...we were on the right track.

Then I asked. "What if we didn't have electricity?" A sea of blank faces. I try again, "Has the power ever gone off at your house during a storm?" (Summer monsoons knock the power off a couple of times every summer here). "When the power goes out, it means you have no electricity."

"I remember when the power went off! I couldn't watch TV, and my fan didn't turn on". This comment then sparked a discussion about what doesn't work without electricity. Everyone agreed that it was VERY dark at night with no electricity, but they liked holding flashlights.

I then read "Electricity". This book compares tasks that are done with and without electricity. Like sewing by hand versus using a sewing machine. Except my students had never seen either (with one exception), so at this point we went into a detailed discussion about how clothes are made. (I now have a sewing center in my classroom). This book sparked the idea for an experiment...would a wet paper towel dry faster hanging outside or inside with a blow dryer inside. Of course, the blow dryer method proved to be the most efficient.

Using electricity to dry the paper towel

To teach them the idea of an open circuit versus a closed circuit, I got out the Energy Ball, and had the class sit in a circle and join hands. I touched one side of the ball and the child next to me touched the other. As long as everyone was touching, the ball lit up and made noise. But if just one person let go of his friends hands, the Energy Ball shut off. Just like shutting off a light. The circuit is open when we are holding hands because the atoms are flowing around us. But if I let go of your hand, the atoms don't flow, and the ball shuts off. We experimented with touching different part of the body; the ball lit up when we all held hands, when we all touched each other's noses, and even when we touched each other's elbows. The kids figured out that as long as you were touching skin, the ball would light up. It didn't take them any time at all to figure this out on their own. Soon they were sitting in small groups, making "circuits" to light up the Energy Balls. (I had a few out)

Since I mentioned the word "atoms" in our discussion, I thought I would ask if anyone knew what an atom was? "It's a guy that lives in your neighborhood!" was the answer I got. While, that is true, I said, an atom is also a very, very, very, VERY, small part of everything we see, and it is also what helps make electricity. I showed them this picture ("Wow, that looks like science a little girl exclaimed when I held it up").

An atom is made up of three parts: neutrons, protons, and electrons. The neutrons and protons are in the middle, and the electrons are around the outside. I drew a atom on the board as I described it, and stuck on paper circles labeled with N's, P's and E's in the proper spot as I talked. The kids then had to go and make their own atoms, with N's and P's in the middle, and E's on the outside.

Throwing in a little bit of literacy with my science, I had dozens of paper circles in various colors labeled with "N", "P", or "E". I gave each student a blank atom on a handout (a circle in the middle of a couple of large ovals, the circle representing the nucleus, and ovals representing the path of the electrons.) The student had to identify the letter and place it in the proper spot of the atom. And, believe it or not, everyone of them did it!

Now it was time to actually make a circuit. Hmmmm.... First thing I did was connect the wires to the battery, the knife switch and a Christmas light, and then had the kids take turns turning off and on the switch. Then I removed the battery. "Why won't the light go on?" Everyone of them figured out pretty quick that it was the battery. Because, as I was told, EVERYTHING uses batteries.

So, I reconnected the battery, but didn't connect one of the wires. "Why won't the light go on?" This one was harder. They thought, and moved things around, when suddenly a little boy yells out, "They aren't holding hands!"

Me: "Huh?" ( I am generally pretty slow on the uptake)

Eric: "The light isn't going on because the atoms aren't going around because the wires aren't holding hands" He holds up the loose wire and shakes it at me. "This needs to be holding hands with the other wires!" Wow....he got it. He used the example of the Energy Ball and all of us holding hands and then letting go. And when I explained the concept to the rest of the class using that terminology, the rest of the class got it too.

I then constructed a circuit diagram using pictures* of the things we were using (as opposed to the scientific symbols) that illustrated the first circuit I created. After everyone had had a turn constructing the circuit, we rearranged the pictures creating different combinations of the components. It didn't take them very long to figure out what combinations worked and what didn't.

*(I downloaded actual pictures of the components we were using, laminated them and then hot-glued them to magnets, so we could construct circuits on my magnetic board)

During one of these demonstrations, my light didn't light up, even though it should have with the configuration we were building. I thought maybe my battery was dead, so I ran and got a couple of other batteries to test out. And another learning opportunity was born. What battery makes the light shine brighter? We ended up testing out all different sizes of batteries, and were amazed to discover that a bigger battery didn't necessarily mean a brighter light.

This ended up being a very successful and exciting unit. (I also touched on Static Electricity, that is the next post...). I think the kids really got a lot out of it. The week following this unit I set up an Electricity Center, where they could construct their own circuits and test batteries on their own. They absolutely loved it.