The aim of this investigation to see the strength of an electromagnetic by varying many variable, and seeing how this affects the performance of the electromagnet.

Physics coursework

Aim

Variables

there are many variables which can increase or decrease the magnetism of the electromagnet. these are the following variables:-

Number of coils:- the more the number of coils the more the electromagnetism because, each coil creates a magnetic field. So the more coils the more magnetic fields thus the magnetism increases.

Current:- this will increase the number of electrons going around the electromagnet therefore increasing the amount of magnetism.

Distance:- the distance the electromagnetic is away from the target object will also decrease the magnetism.

Type of iron core:- the material of the iron core could dramatically change the amount of magnetism.

Length of nail:- The length of the nail will be a controlling factor, because the longer the nail is the more coils can be fitted around the nail, thus making more magnetic fields, and increasing magnetism.

Length of wire:- The longer the wire is, the more oppurtunity for making more coils and increasing magnetism. Also the longer the wire is, and the number of coils increase, also their will be more electrons available to travel around the iron nail, therefore increasing magnetism.

Thickness of wire:- The thicker the wire is, the more electrons can travel through the wire simultanousely, and this will create more magnetic feilds, therefore increasing magnetism.

Voltage:- As potential difference increases in the formula V=I x R, this means as voltage increases so will current and resistance, if current is increased this will alow more electrons to flow, causing the magnetism to increase.

Resistance:- If the resistance of the variable resistor is increased, the voltage and current will drop as a result, therefore decreasing the amount of electrons passing through the wire, and also decreasing the magnetism.

Theory

When insulated wire is wrapped round an iron nail and the ends of the wire are connected to a battery the nail becomes capable of picking up iron filings and paper clips. This is called an electromagnet. The nail is magnetised by the current in the wire. If the battery is disconnected then the iron clips will fall off. This is because most of the magnetism has been lost.

The passage of an electric current along a wire creates a magnetic field around the wire. The fields are in the shape of a series of concentric rings. The more coils used in the electromagnet, the stronger the magnet is. If there is one coil, and another is added, then the two coils have twice the strength of one. This is because the current going through the wire makes the soft-iron core is the factor that induces electromagnetism, as so when there is more current, there will be more wire or or a more magnetised core. Magnets were formed when certain molten metals, (iron, nickel and cobalt,) cool . Normally when the atoms in a non magnetic crystallise, the atoms point in random directions. But because of the properties of the metals mentioned, these atoms line up into parts of the magnetic with similar directions called domains. This is because the earth has a magnetic field, and the atoms in the metal all follow the these magnetic lines and form these domains. This is similar to what happens when an electromagnet is formed.

Magnetic fields are historically described in terms of their effect on electric charges. A moving electric charge, such as an electron, will accelerate in the presence of a magnetic field, causing it to change velocity and its direction of travel.