Coin Attraction: Understanding Magnetism and Its Effects

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SUMMARY

The discussion centers on the conditions under which a coin will remain attached to a magnet, specifically addressing non-magnetic US coins and the hypothetical scenario of an iron coin. It is established that a coin will stay on a magnet only when the magnetic force exceeds the gravitational force acting on it, which is influenced by the magnet's strength, distance from the magnet, and the coin's iron content. The conversation also briefly touches on the properties of light scattering, explaining why the sky appears blue and the sun appears yellow during sunset.

PREREQUISITES
  • Understanding of magnetic forces and gravity
  • Knowledge of material properties, specifically iron content
  • Familiarity with light scattering principles
  • Basic physics concepts related to magnetism
NEXT STEPS
  • Research the properties of different materials in relation to magnetism
  • Explore the physics of light scattering and atmospheric optics
  • Study the effects of distance on magnetic force
  • Investigate the International Young Physicists' Tournament (IYPT) for related challenges
USEFUL FOR

Students and educators in physics, hobbyists interested in magnetism, and anyone looking to understand the principles of light scattering and its effects on atmospheric phenomena.

elnaz
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hi,guys
do you know when the coin will fall from a magnet and when would it stay on it?
 
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Since most US coins are non magnetic I would have to say the coin will only stay on the magnet when it is on top or attached with adhesive. Otherwise it will fall off. ;-)
 
sorry,but i want to mention this situation for an iron coin?:smile:
 


why is the sky blue?
 


elnaz said:
hi,guys
do you know when the coin will fall from a magnet and when would it stay on it?
When the force of gravity is smaller than the force exerted by the magnet, it will fall. That will depend on the distance from the magnet, the strength of the magnet, and the percentage iron content. (100% iron coins will rust and disintegrate pretty quickly, I think, so I don't think you can get coins out of them.)
elnaz said:
why is the sky blue?
Because light is scattered by particles or groups of particles the same size as their wavelength. Most of the particles in the atmosphere are either smaller than visible light's wavelength, or only just big enough. This means only the smaller wavelengths have any scattering, i.e. blue and purple. This scattering across the sky makes the sky look blue. The reason the sky doesn't look purple is because there is less purple in sunlight and we find it harder to see than blue. This explains other effects too. The reason the sun looks yellow is because the blue light is scattered out of the direct sunlight across the sky leaving a shift in the average colour of the sunlight. This effect is especially pronounced when the sunlight has to go through a long distance of atmosphere, e.g. at sunsets. This means only the longest wavelengths can get through i.e. red and orange light. You can see the same effect with silica aerosol, too.
 
elnaz said:
hi,guys
do you know when the coin will fall from a magnet and when would it stay on it?
You're obviously working on IYPT.
 

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