Science Buddies: "Ask an Expert"

Hello everyone:

I'm helping my 8yr old son complete his sicence project. He chose a project from Science Buddies, Does Size of the Wire Matter in an Electrical Circuit.

We've followed the project step explicitly. However, in testing the different size and length of wire (8 & 18 gauge at varying lengths, from 3" to 24") we have determine that in this case there isn't enough resistance in the copper wire to matter or measure. We see only .2 ohm variance in any measure.

I'm confused. For a science project I would think that the result of variance would be more important to show for this project. It would validate the subject matter presented, that size, length, composition, and bundling offers resistance.

I think showing the variance of different conductive material would provide more interesting results to 8 yr. olds.

What gives with this project? Maybe we over estimated/anticipated the results we'd see?

I'd appreciate your input. Thank you.

Dwayne

Hi Dwayne,

The results are the results, no more no less.

You can exaggerate the differences by changing the ranges and scales on the charts. But, the result of there not being much difference is the result.

dadriver wrote:Hello everyone:

I'm helping my 8yr old son complete his sicence project. He chose a project from Science Buddies, Does Size of the Wire Matter in an Electrical Circuit.

We've followed the project step explicitly. However, in testing the different size and length of wire (8 & 18 gauge at varying lengths, from 3" to 24") we have determine that in this case there isn't enough resistance in the copper wire to matter or measure. We see only .2 ohm variance in any measure.

I'm confused. For a science project I would think that the result of variance would be more important to show for this project. It would validate the subject matter presented, that size, length, composition, and bundling offers resistance.

I think showing the variance of different conductive material would provide more interesting results to 8 yr. olds.

What gives with this project? Maybe we over estimated/anticipated the results we'd see?

I'd appreciate your input. Thank you.

Dwayne

I think the procedure is wrong. Look at a related page:
https://www.sciencebuddies.org/mentorin ... ?from=Home

It says, "Note: January 20, 2007. The Experimental Procedure for this project has been modified to correct a mistake. The project now uses a light bulb to indicate conductivity of the test materials instead of an ohm-meter. An ohm-meter should not be used to measure resistance in a circuit with its own voltage source."

which is what you are doing in this project.

That said, I think copper is a good enough conductor that the differences are going to be very, very small. Maybe the related project will be more exciting, where you test different materials.

I'll see if I can get one of the electrical engineering experts to weigh in on this.

Louise

Thanks, Louise. I appreciate your help.

Dwayne