Permanent Magnets: Exploring the Source of Energy

In summary, the conversation discusses the concept of using permanent magnets to generate electricity. It is stated that when a permanent magnet repels an oppositely charged object, no energy is technically being used. However, the stiffness of the electromagnetic interactions of the atoms making up the object counteracts the force. The question is raised about where the electrical energy comes from in this scenario. It is also noted that videos of a fan rotating using this method are fake. The idea of conservative forces is mentioned and it is explained that a positively charged object attracts a negatively charged object. The conversation ends with the reminder that energy cannot be created or destroyed, and that work must be done to pull two magnets apart.
  • #1
DudeWut
5
0
First off, I am new here, so please don't tear me apart too hard if I miss or misinterpret something, I'll cotton on eventually :D

As I understand it, when a permanent magnet repels an oppositely charged object, such as another oppositely charged permanent magnet, no energy is technically being used for the magnets to repel each other, as it is the same principle as putting an apple on a table. The stiffness of the table is counteracting the force of gravity's force on the apple, and that is why the table doesn't just collapse. The stiffness is from the electromagnetic interactions of the atoms making up the table, so in the end it is the EM force counteracting the gravitational force. The magnets repelling each other is caused by electromagnetic interactions.

In this case, if I were to mount negatively charged permanent magnets onto the blades of a fan, and rotate them using the repulsion of a positively charged permanent magnet, then use said fan to power a dynamo that generated electricity, where would the electrical energy be coming from? Energy cannot be created (or destroyed for that matter) so where is it coming from?

Yes, the magnets may eventually lose their magnetism due to surrounding heat and such destabilizing them, but don't magnets still work at absolute zero? In a vacuum environment at absolute zero with no outside forces that can destabilize the magnets at that moment (the friction of the fan turning would generate heat, which would radiate to the magnet and perhaps destabilize it over time) the magnets would still repel, yes? At absolute zero, in a vacuum, there isn't much energy going around that the magnet can readily store and convert to repel it's opposite. As far as I am aware there is no energy change in a magnet anyway. Where is it coming from!?
 
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  • #2
DudeWut said:
...if I were to mount negatively charged permanent magnets onto the blades of a fan, and rotate them using the repulsion of a positively charged permanent magnet

That doesn't work and videos on YouTube that appear to show the fan rotating are _all_ fake.

Magnetic force is a conservative force. Read the first paragraph of this..

https://en.m.wikipedia.org/wiki/Conservative_force

If the fan were to rotate that would be the equivalent of a particle (magnet) returning to its starting position once per revolution (eg traveling around a closed loop) so no net work is done. No work means nothing to overcome friction so it cannot rotate.
 
  • #3
PS Welcome to the forum.
 
  • #4
DudeWut said:
In this case, if I were to mount negatively charged permanent magnets onto the blades of a fan, and rotate them using the repulsion of a positively charged permanent magnet
Note that:
A positively charged object ATTRACTS a negatively charged object.
A positively charged object REPELS a positively charged object.
A negatively charged object REPELS a negatively charged object.

similarly for magnetism:
North and south poles attract each other.
A north pole repels a north pole, and a south pole repels a south pole.

DudeWut said:
Energy cannot be created (or destroyed for that matter) so where is it coming from?
Ever try to pull two magnets stuck together apart?
You have to do work to do that.
The work can be recuperated by moving the magnets back together again.
 

What are permanent magnets and how do they work?

Permanent magnets are objects that produce a magnetic field without the need for an external electric current. They work by aligning the spins of electrons in a specific direction, creating a magnetic field in the surrounding space.

What are the properties of permanent magnets?

Some common properties of permanent magnets include their ability to attract or repel other magnets, their ability to align themselves with the Earth's magnetic field, and their ability to retain their magnetism over time.

What are some common applications of permanent magnets?

Permanent magnets have a wide range of applications, including in motors, generators, speakers, MRI machines, and magnetic levitation trains. They are also used in everyday items such as refrigerator magnets, credit cards, and hard drives.

Can permanent magnets be used as a source of energy?

No, permanent magnets cannot be used as a source of energy. While they can produce a magnetic field, they cannot produce energy on their own. However, they can be used in energy conversion processes, such as in generators, to convert mechanical energy into electrical energy.

What are some ways to make permanent magnets stronger?

Some ways to make permanent magnets stronger include using stronger magnetic materials, increasing the number of magnetic domains within the material, and exposing the magnet to a strong magnetic field during the manufacturing process. However, there are limits to how strong a permanent magnet can be made, as it depends on the properties of the material used.

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