We receive a lot of emails and questions as science fair projects near their deadline. Many parents and their children are looking for answers to their science questions. Some give up the quest and take on an easier project. Others, like this mom, continue to help their child look for an answer, even if there’s no end in sight. Here’s a recent letter from one such mom –

Stored Energy Science Fair Question - How to help your child find the answers they seek

Dear Steve, I am the mother of a 4th grader who has a science project due (just around the corner).

She wants to know, “When an electrical appliance is unplug (sic), what happens to the energy in the cord?”

How can I help her to find her answer? She has been searching for two weeks and has not found an answer. I’ve tried to encourage her to pick another project and then to maybe continue working on this one (after the project is done) for next year. But she seems to think their is something to this one. Can you point me in the right direction????

Dear Lilly – Your daughter came up with an interesting question that only a kid would think about. The simple answer is that there is no “store” electricity in the cord once it’s unplugged. If an appliance has a “capacitor” in the circuit, there might be some residual electricity in the circuit but probably nothing that would easy for a young scientist to test. There really is no safe way for a child to test this other than to pose the question to an electrician.

Like all GREAT science projects, her question leads her to learning more about “stored” electricity. Batteries have stored electricity, of course. Take a quick trip to the Home Depot and look at the yard lights that run off of solar energy. In this case, the sun’s energy is turned into electricity that is stored in batteries to power the lights at night.

“Green Homes” are using solar panels built into the roof tiles to convert solar energy to electricity that is stored in huge batteries in the basement to supplement the need for electricity in the house. As the price of these “photovoltaic” cells goes down, their usage in the home building process will go up, I hope.

In my opinion, your daughter came up with a brilliant question and with your help her question will lead her to a new discovery focused around the science of stored energy. Be sure to document this “discovery” process in her final report… because this is EXACTLY what science is all about. She’s engaged in the scientific discovery process! Please keep her fire burning and keep me posted as to her progress. I’d love to share her project.

– Steve

For more help on working with your child during science fair season, read our Science Fair Tips for Parents.

4 replies
  1. Peter
    Peter says:

    Would it be true you could imagine the electricity not as like water in a river, flowing from one place to another, but more like a message passed hand-to-hand between the electrons in the wire. When the appliance is unplugged, the message simple stops being passed, there’s no electricity to flow around and get ‘stuck’ in the appliance, there’s just no more ‘messages’ being sent. Or something.

    Reply
  2. Erin Edwards
    Erin Edwards says:

    I think of electricity as electrons moving down the wire, electrons hopping into a hole that the last electron just left. When you unplug the appliance the electrons just sit in the last hole they jumped into, and stop hopping. Kind of like like the music stops on musical chairs. When you plug the appliance back in, the electrons start moving again.

    Reply
  3. Ashiley
    Ashiley says:

    Dear steve,

    i have an assessment due on the 16th july 2007!and our whole class has to find out info on any energy we want and i thought of doing heat energy!only because i know nothing about that and so i asked my teacher and she said to look up “where does heat energy come from?” i did look it up on “google” and i tryed them all and there wasn’t any info that said anything about energy. it only was telling me about prices of fuels!

    Reply

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