| |
In lugnet.general, Bradley Dale writes:
> To answer: Is my computer emitting abnormal magnetic fields?
> Materials needed: 8504 Jet Throwbot (or LEGO toy with similar propellor), your
> computer
> Directions:
> 1. Stand away from the computer.
> 2. Spin the propellor by tapping on one side
> 3. Note the direction of spinning.
> 4. Now hold the propellor up against the monitor.
> 5. Spin in a similar manner
> 6. Observe.
> 7. Reply to this message.
> I was playing with Jet near the computer, and when I spun his propellor it
> changed direction and acted weird. It doesn't do this when its not near the
> computer. Is this normal (safe?), or do I need a new monitor? This isn't
> exactly LEGO-related, but I just want to see if this happens to other people.
First of all, yes you are completely safe. there is nothing wrong with your
monitor.
Secondly it's not a magnetic thing, there's no metal (or magnetinc ceramics
even) in ABS so there's no way for the propeller to interact with your
monitor's magnetic field.
So, what's going on?
Although the picture on the screen appears constant (except for the flashing
cursor), it's really flicking on an off somewhere around 60-75 times a
_second_ (we use the unit Hertz, Hz, to say 'times per second'). This sort of
thing happens with fluorescent (neon) lights too. try it! Anyway, what you see
is the propeller is going around faster than 60-75 times a second (or half as
fast or some multiple or...) and as it slows down, it's going just fast enough
so that each time the monitor lights up the propeller it's in the same place
as last time (well, since there's three blades any point where it's lined up
again will do). Then when it slows down some more (friction) the blades don't
quite line up, they're a little late and it looks like the propeller is going
backwards.
There's another place where you can see the effect. In some car advertisments
on TV (cars with definite spokes on the wheel hubcaps) or helicopter blades in
movies,you can see the wheels seem to go backwards, cool huh?
Hope this helps! Send another one!
James (who's happy that he remembers something from science class)
|
|
Message is in Reply To:
6 Messages in This Thread:
  
- Entire Thread on One Page:
- Nested:
All | Brief | Compact | Dots
Linear:
All | Brief | Compact
|
|
|
|
