Magnets have been in usage for thousands of years for various type of applications but hardly do most of the people understand about the working of a magnet. The most common application which you can come across for the magnet is a compass which has been used since the medieval times to find out the directions and for navigation as well. The scientific inventions which are related to the magnet and the magnetism have been around for just a couple of centuries at the most but magnets have been used since thousands of years.
Children always like to play with the magnets because of their capability to attract a small iron objects. Magnets are completely safe as well and therefore there is no problem for the children to play with the magnets and this is the first experience of most of the children with science.
These days we know about the molecule structure of magnets and the magnetism properties of the magnets and therefore are able to understand the working of the magnet properly but thousands of years ago at all seemed like magic because magnets could repel or attract objects towards them or other magnets. These days we have realise that electricity and magnetism go hand in hand and that is why we use the principle of electromagnetism in a lot of applications.
Basics of a magnet:
Here we would be discussing some of the most common facts about the magnet which would enable you to understand the working of the magnets.
-A magnet consist of two poles and one is the North Pole and another is the South Pole.
-The North Pole of a magnet would attract the South Pole of another magnet and similarly the South Pole of one magnet to attract the North Pole of another magnet and if you place to same poles of different magnets in the vicinity they would repel each other. This brings us to the important principle of magnetism which states that like repels and opposite attracts.
-Each and every magnet creates a magnetic field around it.
-The direction of the orientation of the North would always be towards the north pole of the earth. The reason for this is that also be is like a giant magnet and has a field around it as well.
-Whenever you are breaking up a magnet in two or more parts each of the broken parts would have their own North and South poles and therefore you would get a new magnet.
-You can magnetise objects by moving magnets over them a few number of times like you can magnetise the iron nail. This process is known as magnetisation.
These are some of the most basic facts about magnets and magnetism.
Understanding the magnetic field:
To understand the effect of the magnetic field and the existence of the magnetic field all you have to do is to place any kind of magnet on the table and you had to place the iron objects in its vicinity. If you move the magnet towards the iron object you would realise that at some point of time, the iron object would get attracted towards the magnet and cling to the magnet. This happens when the magnetic field which is around the magnet reaches the iron object. For this to happen you do not have to get the magnet in physical contact with the iron object.
For the magnetic field to travel it is not necessary that it should be surrounded by air but it can be surrounded by other mediums as well. A common example of this is that when you have a number of iron objects like paperclips lying on a table and when you are correct one paperclips to a magnet other paperclips would be sticking with that particular people and the chain would be formed and this proves that a magnet can magnetise a paperclip and that paperclip in turn can magnetise another paperclip thus making sure that the magnetic field is passing through a medium like iron as well.
At times in certain applications it is necessary to know the strength of the magnetic field so that the application can be arranged accordingly but this depends on the type of the magnet and the size of the magnet as well. The strength of the magnetic field is not necessarily dependent on the size of the magnet but in some of the magnets it is a factor. Normally the units which are used for measuring the magnetic field are known as gauss or Tesla.
Normally if you look at the horseshoe magnet you would realise that it is a permanent magnet because at no point of time it loses its magnetic properties but not all the applications which use the magnets have the permanent magnets in them because some of them also have what we call as the electromagnets and the electromagnets to not have permanent magnetic properties but rather the only get the magnetic properties when an electric current is passed in its vicinity or whenever they are associated with some electrical phenomena.
The amount of electrical energy which is used in order to convert object into a electromagnets depends on the application which you want to fulfil because if you want to simply because small paperclip then even 1.5 V would be enough but if you’re looking at the real world application like picking Katsina scrapyard then you would need much more power. The basic working principle is that you wind the wire around the object which you have to convert into an electromagnet but do not touch it is equally with the wire and then pass the current through that wire to give the object its electromagnetic properties.
The strength of the magnetic field of the object would depend on the current which you are passing through the wire and also the number of times you have wound the wire around the electromagnet. You can change both of these aspects to increase or decrease the magnetic field which is generated by the electromagnet.
Application of magnets:
The application of magnets are in a wide variety of industries and therefore if you’re thinking that the application of magnets are limited then you are wrong because something like an electric motor always uses a magnet and electric motor itself is being used in thousands of applications.
Magnetic properties and magnetic elements are also being used in computers widely specially the hard disk. The electromagnets are also used in the loudspeakers as well. In the MRI scan as well the magnets are used. There are countless number of applications in which the magnets are being used currently.
We all know that iron is a magnetic material but it is not the only magnetic material and therefore we would be going into the details of the other magnetic materials as well and some of them are nickel and cobalt but some of the other common materials which do not respond to magnetism. There are some other alloys as well which can have magnetic properties. Most of the rare earth metals in the periodic table make for good magnets.
If you look at iron it only receives the magnetic property when it is in the vicinity of a magnet and when the magnet is removed it does not have any kind of magnetic property and therefore it is known as a soft magnet where is the rare earth metals which we spoke about a poor are the hard magnets because even without any other magnet in the vicinity of the act as permanent magnets. Whether the material is magnetic or whether it is non-magnetic, it would always be affected by at least somewhat by the magnetic field which is in its vicinity and the extent to which it is affected by that particular magnetic field is known as susceptibility.
How does a magnet work?
In the early years of the scientific study of the magnets the of the domain theory but after the invention of atoms and molecules another theory was devised which explained the domain theory in much more detail.
Domain theory of magnetism:
Let us explain the domain theory with the help of an example.
Let us assume that the company is making small magnets and supplying them to school. And driver A is supplying them to schools in his tuckand now driver A stacks of the boxes not in an organised way but in a random way and since the magnets are organised in a random way the fields which are coming out from the boxes of the magnets would be working against each other and ultimately cancelling the magnetic field which is around them and that is why the magnetic field is not very strong.
Let us assume a driver B who likes to organise each and everything in a proper way and therefore the lines of the boxes in a proper way. Now instead of the magnetic Fields cancelling each other out they would be working together with each other in perfect alignment to produce a magnetic field which is high in strength as compared to the above example. This would result in the truck in which the boxes are being carried to have a magnetic field of its own and therefore the front of the truck would be acting like the North Pole and the back of the truck would be acting like the South Pole. This is what precisely happens inside a magnet as well.
Let us take the example of iron. A single iron bar contains a lot of sections known as the domains. You can consider each domain is package consisting of magnets. Since these domains are normally not aligned in a proper manner and are in a random direction the magnetic field which is they are cancells each other out. Now when this iron bar is brought into the vicinity of a magnet the domains get aligned and therefore have a magnetic field of their own.
This explains the theory of magnetism properly but it does not explain why when we break a magnet we get to new magnets. This can be explained with an example according to the theory which we have described above. When you break a piece of iron, each piece would have domains in itself and therefore these domains would again provide the magnetic field to the iron bar when it is brought into the vicinity of a magnet.
Similarly, when you’re hitting or heating the magnetic loses its property. This is because that is go to the upper example of the truck which driver B was driving and now let us imagine to simulate hitting or heating you drive the truck erratically up a mountain at great speed. This would cause the boxes to jumble of and the alignment would be stopped and therefore the magnetic strength or the magnetic field would be cancelled out as well.
Now you can argue that this explains setting but how does this explain that heating offer magnet causes it to lose its magnetic properties. For this you have to understand how heat is generated, because whenever heat is generated the atoms are vibrating and that is why the generation of heat is possible and this results in motion inside the magnitude to the vibrating items and that is why the alignment is broken and the magnetic field is eliminated.
Atomic theory of magnetism:
The domain theory does not go into the detail of how these domains are magnetised due to being in the vicinity of a magnetic field and this is what is explained by the atomic theory.
Since the invention of the atomic theory we have come to know that each and everything is further divided into molecules and molecules are for the made up of atoms. Each atoms has a nucleus and has electrons which are rotating around the nucleus. Electrons are carrying electrical energy along with them as well as the dotted around the nucleus and therefore you can say that each and every electron is at least some kind of electric energy. These electrons are responsible for the creation of the magnetism because when electricity flows a magnetic field is created and this is the working principle of many of the electromagnets as we explained above as well as electromagnetism. The domain theory makes the use of domains to explain the magnetism and the atomic theory goes into the details of domains because when a lot of atoms are having such electrons in them spinning in their exes and producing magnetic fields, the resulting magnetic field adds up and produces a larger magnetic field.
This is how magnetism is created inside a magnet and a magnet works.