Physics for Kids: Electricity

I've decided to do a small low stress Physics Club.   Once or twice a week (depending on how much prep time I have), we dip into Mom's Magic Box of Physics (NO PEEKING!).

Inside the box we find a variety of experiments grouped around a theme.  Really, I am shamelessly following my favorite experiments from Janice Van Cleave's Physics for Every Kid.

 So this week we started with electricity (I don't think we need to do laws of motion again!).

We actually started with watching the Bill Nye episode on electricity, so we got a good discussion of the basics. 

Electricity is a moving current of electrons.  What will it move through and why?

We started with a D battery and a variety of conductors and insulators.  You need to warn the kids, if it makes a circuit, the metal will get quite warm, quite quickly, so be prepared to drop it!

Did you notice that the shiny things tend to be conductors?  They shine for the same reason they conduct electricity: lots of loose electrons!

The conductors get warm because  they are imperfect: they are offering resistance to the electrons, so some of the electrons' motion is being converted by friction into heat.

If you have electric heat (or an electric stove or toaster!) that's how it works.

We also did quite a bit with static electricity because it's easy to see exactly what you are doing (rubbing electrons off of your hair) and because it's really hard to build enough of a charge to electrocute anyone!

 We hung two balloons from thread in a doorway.

At first, the uncharged balloons hang loose.

Rub one balloon on a kid's head and the balloons stick together (the negative charge will be attracted to the neutral because it's more positive - opposites attract).


Rub the other balloon on a kid's head and the balloons spring apart because they are both negatively charged (likes repel).

And this negative charge will attract/be attracted to all sorts of things!

Tissue paper, glitter, lint, little paper tents in plastic cups, water, the wall, your head...

It's fun to try different things!

The most fun experiment was one where I couldn't take a picture, but if you only do one experiment do this one: go into a dark room with a balloon and a florescent light bulb.  Rub the balloon on someone's hair and bring it close to the light bulb.

That's why florescent bulbs take so much less energy to run!

The grand finale was our home made electroscope:

I Almost Forgot!

We also built this nifty electric motor!
It's from this very cool kit.

A Bright Idea

We did it! The lamps work great!

Here we have Lampbot (Mxyl's of course). Lampbot is actually a water bottle glued to a takeout plastic container covered with construction paper and spray painted. The socket fit neatly into the bottle neck and I was able to drill a hole in the bottom to put the cord through.

Zorg's lamp was a spice container in a previous life. We filled it part way with sand for ballast and then he added Lego figures (just the duplicates, he assured me). The beauty of this lamp (and Klenda and Leena's lamps) is that you can unscrew the lid and change the contents.

We fished lamp wire (just like the cord on your lamps) through the body. We separated it into 2 wires at the end and stripped the last inch or so of plastic off of each wire. We formed the exposed copper wire into a loop and put it over the screws in the base of the socket. We tightened the screws and that was it for the socket. We pulled the cord on the other end so the socket was nice and tight.

On the other end we had a plug that opened up and squeezed shut onto the cord. You could see little metal teeth which bit into each wire exactly where the prong was. It's a circuit, see? One prong into one wire into the socket, through the socket, into the other wire, into the other prong.

Screw in a light bulb, plug it in, and turn it on!

An Electrifying Start

to our home school year! We started with static electricity, then current electricity, generators and electrical safety. We should be finishing up with making lamps from scratch. More on that later.

Our favorite resources were:

1 The Magic School Bus book- I love the original books - chock full of serious information presented in a fun way that invites co-reading. The books and computer games are also very good for reading to a wide age range. The younger kids pay attention to the semi comic book format and absorb a lot of information, the older kids retain the details and more complex concepts. The only thing they are short on is practical experiments - they have some, but not enough. That's not a quibble, I don't see how much more could be added to the books!

2 Bill Nye the Science Guy - I have most of his shows on tape, but you can usually get them at the library. Fun, manic, ever entertaining, enlightening and encouraging, when I worked at JHU, all the MD PHDs wanted to meet Bill Nye. His tapes are great, even if you want to laugh at the 90s references. We used the episodes Static Electricity , Current Electricity and a more recent episode on Electrical Safety.

3. 1001 Ways to Explore Science and Nature - This is a very useful and kid friendly book which fills the gap between Mudpies to Magnets (a truly terrific book for toddlers to kindergarteners) and 730 Easy Science Experiments (great for 4th grade and up) with a lot of overlap in either direction. In this case, we made a static electricity detector (electroscope) and had lots of fun with balloons, combs, water, salt, etc.

4. Snap Circuits - These were an expensive investment 3 years ago when Mxyl was old enough to start using them. I wouldn't have gotten them. Fortunately, Grammy stepped in and said, "How about as a Christmas present?" If I knew then what I know now, I would have sprung for them. Today Mxyl deftly explained, modeled and helped Klenda, Zorg, and Leena build a variety of circuits (including teaching me what a short circuit is and how it works!). Along the way he modeled conductors, insulators, resistors, fans, lights, telegraphs, sirens and more! WOW! Substitute teachers are cool!!!

Hm. Oob just climbed on my lap and I discovered that he had no diaper. Hm. A second Diaper Houdini. Got to go.