This is a good question and a bit tricky to answer, but I’ll try my best.
Every magnet has two sides: a north pole and a south pole. We use these names because if you hang a magnet from a thread, the magnet’s north pole points (almost) toward the north direction.
This is because the Earth’s core (its center) is a large, weak magnet. Your little, strong magnet lines up with Earth’s magnetic core, so it points north. That’s how a magnetic compass works. But, before we discuss why do magnets attract or repel? Let’s first discuss how do magnets work.
How Do Magnets Work?
Magnets are objects that produce magnetic fields and attract metals like iron, nickel, and cobalt. The magnetic field’s lines of force exit the magnet from its north pole and enter its south pole.
Every substance is made up of tiny units called atoms. Each atom has electrons, particles that carry electric charges. Spinning like tops, the electrons circle the nucleus, or core, of an atom. Their movement generates an electric current and causes each electron to act like a microscopic magnet.
In most substances, equal numbers of electrons spin in opposite directions, which cancels out their magnetism. That is why materials such as cloth or paper are said to be weakly magnetic. In substances such as iron, cobalt, and nickel, most of the electrons spin in the same direction. This makes the atoms in these substances strongly magnetic—but they are not yet magnets.
To become magnetized, another strongly magnetic substance must enter the magnetic field of an existing magnet. The magnetic field is the area around a magnet that has magnetic force.
All magnets have north and south poles. Opposite poles are attracted to each other, while the same poles repel each other. When you rub a piece of iron along a magnet, the north-seeking poles of the atoms in the iron line up in the same direction. The force generated by the aligned atoms creates a magnetic field. The piece of iron has become a magnet.
Permanent or hard magnets create their own magnetic field all the time. Temporary or soft magnets produce magnetic fields while in the presence of a magnetic field and for a short while after exiting the field.
Some substances can be magnetized by an electric current. When electricity runs through a coil of wire, it produces a magnetic field. The field around the coil will disappear, however, as soon as the electric current is turned off.
Why Do Magnets Repel?
If you hold two magnets the wrong way around, they push apart – they repel! In other words, if you hold two magnets together so that like-poles are close together (two norths OR two souths), they repel. Try it! It feels like the magnets are surrounded by an invisible rubber layer pushing them apart. That invisible layer is called a magnetic field.
Like-poles repel: We can use curvy arrows (called field lines) to draw the shape of the magnetic field around magnets. The arrows always start at the magnet’s north pole and point towards its south pole. When two like-poles point together, the arrows from the two magnets point in OPPOSITE directions and the field lines cannot join up. So the magnets will push apart (repel).
It’s only when you hold unlike-poles together (a north pointing to a south) that magnets stick together (they are attracted). Now, the magnetic field acts like a stretched rubber band pulling the magnets together. (Be careful; two strong magnets can pinch your skin).
Unlike-poles attract: When a north pole and south pole point together, the arrows point in the SAME direction so the field lines can join up and the magnets pull together (attract).
Why do magnets attract or repel?
You’ve probably heard of energy. Energy is required to create movement.
A stationary car starts moving when the petrol it contains burns. This is because petrol contains stored energy that is released when it is burned.
When this stored energy is released, some of it converts to kinetic energy. Scientists call this stored energy “potential energy” and call the energy of motion “kinetic energy”.
When you start running, it’s because the energy stored in your food is released and some of it is converted into kinetic energy.
What does this have to do with magnets? Well, the magnetic field that surrounds all magnets contains stored energy. But there is a way to change the amount of stored energy surrounding the magnet. And the way you change it will tell you which way the magnet will move.
What forces repel magnets?
Opposites attract. To explain why magnets repel each other, a north end of a magnet will be attracted to the south of another magnet. The north and north ends of two magnets as well as the south and south ends of two magnets will repel one another. The magnetic force is the basis for electric motors and attractive magnets for use in medicine, industry, and research.
To understand how this repulsive force works and explain why magnets repel each other and attract electricity, it’s important to study the nature of magnetic force and the many forms it takes in various phenomena in physics.
What happens when magnets repel?
A magnet’s magnetic field is the area around it where metallic objects are affected. The area of the magnetic field where the magnet’s force is strongest is called the magnetic pole. When a magnet is hung freely rotating, it rotates in a north-south direction. The north end is called the north pole or north pole of the magnet. The other end is called the South Pole.
When two magnets are brought together, the opposite poles will attract one another, but the like poles will repel one another. This is similar to electric charges. Like charges repel, and unlike charges attract. Since a free-hanging magnet will always face north, magnets have long been used for finding direction.
Thousands of years ago, Chinese navigators used a magnetized needle floating in the water to indicate direction. This made a simple type of compass. Columbus and other explorers also used magnetic needles as a compass to help them cross the Atlantic.
The earth is like a giant magnet, but unlike two freely hanging magnets, the north pole of a magnet is attracted to the earth’s north pole. The earth is the largest magnet on earth itself. It is mainly composed of iron and nickel.
The outer core is made of molten rock that contains metal. The center or inner core of the earth is also made of metal. When the inner core moves against the outer core, the earth turns into a giant magnet.