My electromagnet isn't strong enough. Due tomorrow.

[marier4him]

Homework Statement

Hi, I've been trying to figure this out for days. I've wrapped an insulated wire that I got at Lowe's around a large metal nail. I then connected it to a knife switch and a 9v battery (per the directions). The nail is supposed to pick up 30 paperclips. I've tried wrapping the wire very tightly and more loosely, but nothing helps.

Thanks in advance,

Marie

Homework Equations

The Attempt at a Solution

 

[Simon Bridge]

Welcome to PF;
In what way does it not work?
i.e. I guess it does not pick up 30 paperclips ... how many does it pick up?

Have you used an ammeter to find the current?
Have you checked the resistance of the wire?
Is the nail iron or steel or some other metal?

 

[marier4him]

It's only picking up 6 paperclips. I don't know how to check the resistance of the wire and I don't have an ammeter. The nail is 6" and steel. How much of the of the nail should be covered with the windings?

 

[marier4him]

and thanks for trying to help.

 

[Simon Bridge]

It's OK I had to step out for a bit.

You want to fit as many windings on the nail as you can ... more windings = more magnetism.
The nail has to be made of iron for best effect.

Does the battery get warm?

It is impossible to be exact without meters.
You can pick up a multimeter for a few dollars these days - it will do everything.
If you are going to mess with anything electronic you must have one: essential tool.

 

[marier4him]

The battery gets very warm almost hot. I've tried an insulated wire with a solid copper core a little tough to wind, but doable. I also tried an insulated copper wire made of strands. I don't think our big box stores sell iron nails. I covered almost the whole nail in windings.

 

[Simon Bridge]

Sounds like the wire you are using is too fat.
Try thin wire.

 

[marier4him]

I tried the thin wire first, but I'll rewrap and try again. Maybe the windings weren't tight enough.

 

[Simon Bridge]

Maybe a fatter nail?
Thinner wire means you can fit more turns on it.
You could try overlapping windings - going back and forth up and down the nail.