Science Buddies: "Ask an Expert"

i was following one of your project guides called "Which materials are the best conductors".. and i was thinking that if i done everything u said it would work out right.. but when i connect the battery to the light bulb ( yes im using wire leads ) the light bulb does not come on !! plzz help asap

Hi!
It's hard to tell what went wrong, could you please give us a step-by-step explanation of exactly what you attached to what so we can see where the problem is? Thanks, in the meantime, keep trying and double check to see if everything is attached securely and that the battery is working. Looking forward to hearing more about the project!

well.. i have a brand new 6 bolt battery ( one of them lantern ones ) and i have an alligator clip attached to each terminal ( + and - ) .. i have a light bulb with wire leads.... the other ends of the aliigator clip are connected to the wire leads..but when i connect it the light doesnt come on

If I am reading your circuit description correctly, you have connected a light bulb across a 6 volt battery using some alligator clip leads. I can think of some possibilities:

1) What type of light bulb is it? Is it a PR4 flashlight battery? A PR4 light bulb is designed to be run by 4 battery cells (each cell producing nominally 1.5 v totaling 6v). If you are using the correct rated light bulb, then the bulb may be defective (broken filament or bad internal connection).
2) The electrical connections between the light bulb and the wire leads maybe defective (broken wire or solder joint or dirty physical contact).
3) The alligator clip leads maybe defective (broken wire or solder joint).
4) The battery maybe defective (yes, even new batteries are sometimes defective).

When simple circuits like this don't work for me, I haul out a multi-meter. If you have one, you can unhook the battery and measure the battery voltage. You can use the ohms scale to check for continuity of the alligator clip leads, lamp wires, lamp and filament to help isolate the problem.