Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Harmful Levels of Magnetic field exposer?

  1. Feb 4, 2008 #1
    1. Are rare earth magnets harmful to handle and if so what strengths and sizes are safer?

    2. Is the magnetic field produced by an electric car strong enough to have harmful effects on a person s health.
  2. jcsd
  3. Feb 4, 2008 #2
    No and no.

    MRI's are very safe, and they produce some huge magnetic fields. Anything you can dig up in your backyard pales in comparison.

    But I wouldn't swallow them anyway if I were you.
  4. Feb 4, 2008 #3


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    There are no known health consequences of strong magnetic fields. Your rare earth magnets are much more dangerous due to their potential to mechanically crush or otherwise injure your body when they snap together, or impact something and break into shrapnel.

    - Warren
  5. Feb 4, 2008 #4

    Chi Meson

    User Avatar
    Science Advisor
    Homework Helper

    Only if said magnetic field contributes to the electric car running over your leg.
  6. Feb 4, 2008 #5
    Magnets are COOL! Lol, even at incredibly high strengths they can still be safe, and yet, if strong enough, they can affect move anything, even people.
  7. Feb 4, 2008 #6
    During WWII they used very strong magnetic fields to degauss metal ships to protect against magnetic torpedos. They men who worked in these intense fields for years had no higher instance of disease than the men who did not during peace time. In other words, magnetic fields are apparently harmless.
  8. Feb 5, 2008 #7
  9. Feb 5, 2008 #8
    That seemed to be talking about electromagnets only, not permanent or reare earth magnets.
  10. Feb 5, 2008 #9
    More specifically, AC electromagnets.
  11. Feb 5, 2008 #10
    Yeah, that is why I asked about rare earth magnets. I though that it was common knowledge that electromagnets could be harmful depending on strength. For example people who live under power lines. This article seams to suggest that even low level electromagnetic fields can cause harm over time which is why I asked about electric or hybrid cars. Is it safe drive in one for extended periods of time?
  12. Feb 5, 2008 #11
    We have a hybrid Civic. No problems yet, and my mom's newly replaced knee doesn't jerk forwards when the electric kicks on.
  13. Feb 5, 2008 #12
    The article claims that even the exposure we get in everyday life from electric blankets, electric razors, blow dryers could accumulate and cause damage to DNA in our brain cells. A hybrid car has got to create an EMF more powerful than an electric razor, and if you like to go on road trips, the exposure times could be hundreds to thousands of times longer.

    However, maybe the amount of loss of brain cells is small enough to only make you slightly stupid or slightly senile. The rats had significant loss. I am not a biologist, so I can't say what is significant or not, but if there is any noticeably affect on my behavior, intelligence, memory, motor skills, social skills, or personality I would like to know.
  14. Feb 5, 2008 #13
    But, hybrid cars don't use the electric very much on extended drives. They mainly use them when leaving stops, so are better for in city, stop and go driving.
    Last edited: Feb 5, 2008
  15. Feb 5, 2008 #14


    User Avatar
    Science Advisor
    Homework Helper

    Quite a few people are killed every year by MRIs - mostly by some idiot leaving a steel oxygen cylinder in the room when they turn the field on !!!

    I had a friend doing a PhD on NMR - he reckoned he got a headache and wierd flashing lights if he had his head under the magnet when adjusting a sample - but these were much higher field than an MRI scan, and weird flashing lights were part of his personality!
  16. Feb 5, 2008 #15
    I got to think some more. The electric motor in hybrids is prolly DC anyways, even if its multiple phase its not AC, which is what the article repeatedly implied.
  17. Feb 5, 2008 #16
    That has to HURT!

    I wonder if that was due to the magnetic field or any audio vibration from the parts? I know I can tell when a TV is on, even if it's in another room. Nothing to do with magnets, just hearing the very high-pitched sound it gives off. I can see that giving me a headache if it was too loud, or too high, or just affecting some people differently.
  18. Feb 5, 2008 #17


    User Avatar
    Science Advisor
    Homework Helper

    The floating frogs are basically unharmed.
  19. Feb 6, 2008 #18
    When you say electromagnetic field do you mean light radio waves and UV light?
  20. Feb 6, 2008 #19
    What is the difference between a DC electro-magnetic field and an AC electro-magnetic field?

    The article I posted shows evidence that the fundamental cause of harm is the iron content in certain cells and their interaction with the magnetic field.
    How does iron interact with a DC magnetic field vs an AC magnetic field?
  21. Feb 6, 2008 #20
    Id assume you can just generalize and say that perhaps in the presence of a DC magnetic field, anything with a magnetic moment in your body would attempt to align itself to the field. In an AC if its constantly changing sign, it seems logical to assume it could cause much more damage, perhaps just due to the "vibrations" caused, and the constant change. Maybe it affects bonding in cells or division.

    Or am I completely mistaken ?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook