Science for Kids/Magnetic Propulsion

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Expert: Dan Fink - 11/4/2009


Question
My daughter (6 years old - grade two) has to build a vehicle powered only by magnets. No motors are allowed. She is wanting to build a boat. My question is, if we have a stationary magnet and several on a paddle type wheel in contact with the water, with opposite polarity would it be enough to propel a small boat?

Answer
Hello Scott --

I work with magnets for a living, for a company that designs wind turbine generators that can be built in third world countries, and in your garage at home. With years of experience here, I can assure you that magnets are NOT a source of power or energy. There is no such thing as a vehicle powered only by magnets -- that would be called a 'perpetual motion machine' and is not possible under he laws of physics.

Magnets are a handy way to *transfer* energy around, without physical contact--but in all cases, someone or something has to physically *push on* the magnets. The energy transferred comes from the push (from a human, moving water, moving air, burning fuel, moving electricity...), not from the magnet itself. And there is always a loss of energy during the transfer.

The device you describe might give a couple of rotations before it stopped, because *you* put energy into the system by aligning the magnets to repel each other. But losses from pushing on the water, friction, magnetic eddy currents, the Earth's magnetic field, and so on would quickly bring it to a halt.

DAN  

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Dan Fink

Expertise

Though my experience is mostly in the fields of electricity, magnetism, and physics, I have a broad science background. My career is in the field of alternative power sources -- solar, wind, water and battery power. But any questions about electricity, magnetism, energy conservation, power generation, electric motors, and even general physics are very welcome--especially from kids. They ask the best questions of all! I pride myself in answering science questions accurately, with ideas for SAFE, easy experiments that kids can perform by themselves--and that let them prove the answers to their own satisfaction. I think science should be fun, and available to everyone, regardless of age.

Experience

I have volunteered in our local public schools for 5 years. I currently make presentations at our schools about electricity and magnetism, with a focus on solar, wind, water and other alternative power sources. I try to demonstrate at our schools how easy it is to make electricity, with simple devices using spinning magnets and coils of wire--powered by wind, water, bicycles, gerbils...etc. And of course solar panels! I am the webmaster of Otherpower.com, an alternative energy website. I have lived 10 miles from the nearest power pole for 11 years--I make all my own electricity from scratch with sun, wind and water.

Publications
Otherpower.com
Wondermagnet.com
Co author of the book "Homebrew Wind Power" ISBN 978-0-9819201-0-8
My articles appear regularly in such magazines as Home Power and Back Home
Education/Credentials
BA Technical Journalism


Education/Credentials
BA Technical Journalism

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