Magnets were first discovered in the city of Magnesia, a small city in Asia. Magnets are objects that can attract other objects made of certain metals. Magnets are called natural magnets because they come from nature.
Magnets are also called brave iron. The shape of the magnet is various, that is in the form of needle, cylinder, rod, horseshoe or horseshoe and ring. Naming on the magnet is adjusted to its shape.
Magnets have two poles, namely the north pole (U) and the south pole (S). The values of the two poles are the same, for example south and south, confronted, then both poles will reject. However, if the two poles are different, ie north and south are faced, it will cause attraction between the two magnets.
Objects are magnetic and non-magnetic
Magnets can attract or reject objects around them. This means that the magnet has a force that can move objects. This force is called the magnetic force.
But not all objects that are subject to magnetic force can move. Objects that can move, when subjected to a magnet, are magnetic. Whereas an object that cannot move, when subjected to a magnet, means that the object is nonmagnetic.
Magnetic objects can be made of iron, steel, cobalt, or nickel. Non-magnetic objects can be made of gold, plastic, copper, aluminum, glass, rubber, wood or paper.
The use of magnetic force in everyday life
Compass is a tool used to determine the direction of the compass, and is usually used by sailors and pilots. On the compass there is a magent needle that always points north and south. The discovery of magnetic needles that always lead north and south, occurred in China.
The compass was developed by the Chinese in the nineteenth century, in the form of a floating needle and a rotating needle. William Thomson and 1 st Baron Kelvin or Lord Kelvin made a compass that was acceptable to all countries, in 1877.
2. Scrap metal conveyor
Transporters or cranes use electro-magnets that are electrified to transport scrap metal or steel. Scrap metal or steel will stick to the carrier as long as the electric current continues to flow, and if turned off, the scrap metal or steel will be released. The tool also serves to separate old iron and steel from other non-metal objects.
3. Scissors tip and screwdriver
The end of the scissors is magnetized so that it is easy to pick up and look for needles if scattered. The tip of the screwdriver is magnetized so that the screw to be attached is attached to the end of the screwdriver, making it easy to install it.
4. Maglev train
Maglev stands for magnetic levitation which means it floats on a magnet. Maglev trains do not have wheels with rails made of magnets, so they can make trains move.
How to make magnets
Magnets that are currently used by humans are magnets that are intentionally made by humans using iron, steel, and a mixture of the two materials. Iron and steel are made magnets because they are ferromagnetic. Ferromagnetic means having the ability or strong magnetic properties.
1. How to rub
Making magnets by rubbing the magnetic poles on iron or steel that will be made as an artificial magnet.
2. How to induce
Making a magnet by bringing the magnet closer to a magnetic object that will be used as a magnet.
3. How to flow electricity
Making magnets by using an electric current is called an electric magnet or electromagnet.
Gravitational force is the force that pulls all living and non-living objects towards the center of the earth. The effect of gravity can cause objects to fall to the ground, because they are pulled by Earth’s gravity. As a result of the absence of gravitational force, ie
- Rivers, lakes and oceans will dry up because water easily disappears into space
- Stones will fly.
- Earth’s atmosphere will run out of space.
Friction is a force that holds the object from moving so it does not move when pulled or pushed. Friction can be reduced by using a lubricant, smoothing the surfaces of two objects that rub against each other, sanding surfaces, and minimizing surfaces that rub against each other. The friction force can be enlarged by enlarging the surface of the object, attaching rubber, and making patterns on the surface of the tire.