In things that aren’t magnetic, electrons send their magnetic pull in different directions, leading to failure. In metals that are magnetic, the electrons are all facing the same way. To see if a piece of metal is magnetic, you have to see if it repels another magnet, not attract. Magnets can also lose it’s magnetism if it is heated.
Every magnet has a north and south pole. The north pole, also known as the north-seeking pole, attracts the south pole/south-seeking pole, while it repels the same pole.
Magnetism is extremely useful, and we can normally find them in our everyday life. For example, many of us use magnets to stick things on the fridge, for compasses...etc. Doctors and surgeons also take magnetism to their advantage. They use magnetic resonance imaging (MRI), which is a medical imaging technique used in radiology to visualize internal structures which helps them to spot problems in a patient’s body without invasive surgery. An MRI machine uses a magnetic field to align the magnetization of atoms in the body. MRI scans are now used frequently nowadays by doctors to help diagnose cancer, brain tumors...etc. It is the safest and best way to see inside the human body without performing surgery.
Another use for magnetism is for reading information on credit cards. All credit cards and debit cards have a magnetic strip on the back which helps a special machine read the information on it and access their account.
Metal detectors also rely on the basis of magnetism. As the magnetic field generated by the transmitter coil pulses back and forth, it causes any conductive objects on the ground to generate their own magnetic fields. The metal detector can also determine approximately how deep the object is under the ground based on the strength of the magnetic field it generates. The stronger the magnetic field, the closer to the surface it is. Sometimes, if an object is too deep under the ground, it will not detect it.
A magnetic field is the space around a magnet. You can see the shape of the magnetic field of a bar magnet using iron filings or a plotting compass. Below is a diagram of a magnetic field of a bar magnet. Magnetic fields are very useful, as explained above with the idea of the metal detectors.
An electromagnet is an electricity generated magnet. This happens when electricity flows through a coil of wire. To strengthen an electromagnet you have to increase the number of coils of wire or increase the current in the wire. You can also use a iron screw as a core (wrap the wire around the screw). Below is a diagram of the magnetic field of an electromagnet. As you can see, it is similar to the magnetic field of a bar magnet.
The Earth is like a huge magnet, it’s liquid core contains iron, and as it moves, it creates an electric current that causes a magnetic field to surround the Earth. The North Pole and the North Magnetic Pole are not the same thing, as the north magnetic pole is constantly moving, whereas the north pole stays in the same place. Therefore, if you rely on a compass to point you to the north pole, it will probably direct you to the north magnetic pole instead.