# Magnetic powder in a solenoid - how would it react?

• EddieP
In summary: When there is no externally applied magnetic field, the particles of the powder will clump together in a random fashion. The orientation of the resulting magnetic field will not resemble that of a standard iron core electromagnet.
EddieP
Suppose I have a plastic tube about 70% full with magnetic powder, with a copper coil solenoid around the cylinder.
By "magnetic powder" I mean each particle is actually a tiny permanent magnet with its own magnetic field. - like you can see in this video
When there is no externally applied magnetic field, the particles of the powder do their best to clump together and find north and south poles to complete their magnetic circuit.
What happens when we turn on the solenoid? How would the magnetic powder react? Would the orientation of resulting magnetic field resemble that of a standard iron core electromagnet? (like the one shown here - http://www.pirate4x4.com/tech/billavista/Wiring/Part2/images/elmag_400.jpg )
Would the magnetic field of the powder interfere with the field in the current carrying copper?

Last edited:
EddieP said:
What happens when we turn on the solenoid? How would the magnetic powder react?

Assuming that you are only filling the tube 5% :

Microscopically the powder will form theads ( or rather thin chains ) parallel to the tube.

Macroscopically these chains will take a form like an ear trumpet at the ends of the tube.

The powder magnets will always try to find some space in the neighbourhood, arranging themselves so that they will destroy ( eliminate ) the magnetic energy.

You say:
EddieP said:
do their best to clump together and find north and south poles to complete their magnetic circuit.
but I don't like this formulation: North and south poles are nothing ( but an educationally approach ). They are not "small particles" concentrated e.g. at each end of a permanent solenoid magnet. They are just a surface that is crossed by a magnetic field, where the permeabilities on each side of the surface are different. You cannot saw through a magnet and hold the north pole in your hand. You will just create a new surface that becomes a "south pole" ( out of nowhere ).

Last edited:

## 1. What is magnetic powder and how is it used in a solenoid?

Magnetic powder is a fine, iron-based powder that becomes magnetized when exposed to a magnetic field. It is commonly used in solenoids, which are coils of wire that produce a magnetic field when an electric current is passed through them. The magnetic powder is used to enhance the strength and direction of the magnetic field produced by the solenoid.

## 2. How does magnetic powder react when placed inside a solenoid?

When placed inside a solenoid, the magnetic powder aligns itself with the magnetic field produced by the solenoid. This causes the powder to clump together in the direction of the magnetic field lines, creating a more concentrated and directed magnetic field.

## 3. Does the amount of magnetic powder used affect the strength of the solenoid?

Yes, the amount of magnetic powder used can affect the strength of the solenoid. Generally, a larger amount of powder will result in a stronger magnetic field, as there is more material available to align with the magnetic field produced by the solenoid.

## 4. Can the magnetic powder be removed from the solenoid?

Yes, the magnetic powder can be removed from the solenoid by simply shaking or brushing it off. However, some powder may remain embedded in the material of the solenoid, so it may not be possible to completely remove it.

## 5. Are there any safety precautions to take when handling magnetic powder in a solenoid?

Yes, it is important to handle magnetic powder with caution as it can be hazardous if ingested or inhaled. It is recommended to wear gloves and a mask when handling the powder to avoid any potential health risks. Additionally, the solenoid should be turned off and unplugged before handling to prevent any electric shocks.

Replies
1
Views
534
Replies
5
Views
114
Replies
1
Views
1K
Replies
4
Views
9K
Replies
10
Views
1K
Replies
1
Views
4K
Replies
8
Views
1K
Replies
7
Views
426
Replies
3
Views
2K
Replies
8
Views
2K