Science Buddies: "Ask an Expert"

Hi,

There are small magnetic detectors that range no more than 5 cm. I want to either boast that detection field or build a new one that at least can detect a field of 30 - 50 cm or a couple of feet. What should I use to do that?

Thanks!

Hello,

The Ask an Expert form is for students who are working on science fair projects. Is this question related to a science fair project? If so can you tell us a bit more so we can help?

Audrey