Wednesday, April 28, 2010

Science Experiment – Battery Power

blog pictures 007M is obsessed with batteries and electricity lately.  I don’t know how many times he has come to me, screwdriver in hand, to see which kind of battery and how many of them a particular toy takes.  He is always trying to figure out how things “go”.

So you can imagine his excitement when I told him our experiment for the day would be trying to light a flashlight bulb with a battery and aluminum foil.

We had a little discussion about how metal is a conductor (his newest word now) of the energy stored inside a battery.  Wires can take this energy to working parts, as can almost any metal, even aluminum foil.

Interestingly, he asked me, “how do wires send the electricity?  There are no holes in wires!”.  It’s so neat to see his little brain working… the idea of electricity traveling inside a wire – well, it would have to have a hole to get into it, right?  So I explained that the whole wire – even the outside – is a conductor, and the energy runs along it.  He asks some tough questions sometimes and I’m not sure my answer entirely satisfied him.  Ah well, he has time to learn!

To do this experiment, take the small bulb out of a flashlight.  You want something like a 2 watt bulb, maybe 3 watts at the most.  You also need scotch tape, a D battery, and two lengths of aluminum foil rolled up tightly.  Ours were about 12” long I’m guessing.

Use the tape to attach one end of each foil “wire” to the battery.  One will be attached to the negative side:blog pictures 014 and one to the positive side:blog pictures 015

Next, take the opposite end of one of the foil “wires” and wrap it around the base of the pictures 016Get it as tight as you can, and use tape to secure it if you need to.  This was the toughest part for us… those tiny bulbs are a bit hard to manage.

Next touch the very bottom of the bulb with the loose end of the other “wire”.  Your bulb should light up!  M loved doing this part!blog pictures 002Energy from the battery circles through the foil and lights up the bulb.

No pictures of this, but we also used one length of foil and a AA battery.  We placed one end of the foil at one end of the battery and the other end of the foil at the other end of the battery.  Then we placed our fingers over the foil at the ends of the battery and could feel it get warm, then hot!  The energy in side the battery was going through the foil and making it and the battery very warm.   (Note… you don’t want to do this with much bigger batteries, at least with small children, because at some point it could burn.  These batteries are not going to electrocute anyone, but it’s always best to be safe!)  I wonder if this would be a good way to test batteries and see if they are still good?!

For more science, see Ticia’s Science Sunday posts here!

Have a beautiful and energy-full day! :)


  1. Very cool. I'll have to let my bigger kids try that one...and let the little ones watch and "help"....Last summer we had an electricity science kit that I picked up at Target that did a similar thing. They LOVED it. It also used a switch and let them power a fan(think dinky fan). So facinating, even for me.

  2. Oh man, I remember doing this in sixth grade and LOVING it. I was thinking I'd get an electricity kit to try out sometime, but this works great as well.

  3. I love this! It reminds me of when my son was doing a project for a science fair, and he actually played around with his battery and light until he figured out how a dimmer switch worked. Great hands on science!

  4. M is such a little engineer! This experiment is AWESOME, and I am sure that he went away thinking that his mommy is the smartest person who ever lived. You are doing such a wonderful job following his interests!

  5. Have you tried making a battery-powered electro-magnet? My little one didn't understand what it was while we were reading it in a book one night. So, I called his grandpa, who made a model for him.... a D battery with wire on each end, and a nail with the wire coiled around it. When you touch the ends of the wire to the battery, the nail will pick up washers, small bolts, and nuts.

  6. Awesome experiment! We're getting to the point where Crumpet is asking questions I can't answer, too. Yikes. Thank goodness for the internet!

  7. oo my son would totally love this experiment! Bookmarking it :-)


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