Today we will learn how to make a homemade magnet thanks to the earth's magnetic field and with simple tools. It is always useful to have one at hand.
Before we start, a few basic notions: iron is a ferromagnetic material, which means that it is made up of small iron crystals with magnetic properties. The problem is that they are "disordered", so to speak. If we manage to bring all these particles together, the iron object shall be magnetised. This logic is followed, for example, by a nail when it is attached to a magnet. The nail is magnetised and behaves almost like a magnet. magnet.
You will need:
- An iron bar.
- A hammer.
- A compass.
We take the iron bar with one hand, and with the other we hit it with the hammer. The bar will then be magnetisedHow do we get it to increase its magnetising power? We will have to try to align it with the Earth's magnetic field.
To do this we will use the compass. The iron bar must be oriented in the North-South direction and inclined towards the ground, as shown in the drawing. However, the inclination depends on the latitude where we are. In the northern hemisphere, the northernmost end should be lower. The followers of How To Southern hemisphere countries will have to do it the other way around.
What about the angle of inclination? If we are at the equator, the bar will have to be horizontal. Therefore, no tilt. The further towards the pole we go, the steeper the inclination should be. In Spain, as a guide, it should have an angle of about 40 degrees.
The explanation for this process is that the magnetic domain rotates, and those that align in a north-south direction become larger. Its permanence is complicated, as it involves "encouraging" the domains to maintain alignment.
To test the magnetisation of the bar or any other object, test with small particles such as iron filings or grate some steel wool.
For demagnetise one option is to heat the object to the so-called "Curie point", as the heat excites the particles and causes them to become "misaligned".
You can let us know how the experiment went in the forum.