interesting fact about magnets part - 2

WHAT WOULD THE WORLD BE LIKE WITHOUT MAGNETS?

No navigation: -

In uncharted landscapes, explorers rely on compasses to find their way, using a floating magnetic needle to point to Earth’s magnetic north pole. It is thought that the first practical compass was made in 1274, providing an invaluable tool for navigating the seas and oceans, and eventually leading European explorers to the Americas.

 

No data storage:-

From cassette and video tapes, to floppy disks and hard disks, many of our early methods of digital data storage relied on magnetic tape. To store the information, a current is passed through a coil of wire, creating a magnetic field that changes the direction of the magnetic domains of tiny metal particles embedded in the tape.

 

No radar (or microwaves):-

The radio waves used in radar, and the microwaves used to cook your dinner, are produced by a piece of equipment called a magnetron. A powerful magnet is used to curve the paths of electrons as they move through a tube. They fly past specially designed cavities, causing them to resonate and producing electromagnetic radiation.

 

No electricity:-

We knew about electricity before the 1800s and had even created chemical batteries, but electrical generators relied on magnetism. The invention of the dynamo in the 1800s paved the way for the invention of the light bulb, and then all of the other electrical gadgets that we use today followed. Even now most of our electricity is generated using magnets.

 

No music: - Well, only live acoustic music. Speakers rely on magnets to produce sound. An electrical signal is passed through an iron coil attached to a fabric or metal diaphragm, turning it into an electromagnet. This is either attracted to, or repelled by, a nearby permanent magnet, making the diaphragm vibrate and reproducing the sound.

No fridge magnets:-

It might seem like a small loss, but these humble magnets defy gravity as they cling to the door of your fridge. Sold as souvenirs across the world, fridge magnets are an everyday reminder of the strength of the electromagnetic force.

 

Difference between Permanent magnets and electromagnets

There are two main groups of magnets, each with different properties and uses. Permanent magnets, like the ones that you might stick to your fridge, have a fixed and constant magnetic field. Electromagnets, used in headphone speakers, for example, are only magnetic when a current is passing through them.

PERMANENT	VS	ELECTRO
Permanent magnets are made from ‘hard’ magnetic materials, capable of holding their orderly magnetism.	MATERIAL	Electromagnets are made from ‘soft’ magnetic materials, which only line up when a current is applied.
The strongest permanent magnets are made using neodymium. Once made, their strength is fixed.	STRENGTH	The strength of electromagnets can be varied by changing the number of wire coils or varying the current.
Permanent magnets have no moving parts, and are very cheap and simple to use.	SIMPLICITY	Electromagnets are more complex and costly, and they generate heat when used.
Permanent magnets can be damaged by knocks, chips and other magnetic fields.	FRAGILITY	Electromagnets do not work without electricity, and can overheat if not properly cooled.
Permanent magnets are always magnetic, unless they are dropped or damaged.	ON OR OFF	Electromagnets can be easily turned on and off at just the flick of a switch.

COSMIC MAGNETISM

Magnetic fields in space are responsible for awe-inspiring and sometimes dangerous events

Magnetisms responsible for space weather, including the coronal mass ejections that can interrupt GPS, telecommunications and power grids. It is also the force behind the stunning spectacles of both the northern and southern lights. Almost all of the plasma in the universe (as far as we know) is magnetized. As charged particles whip past one another, they generate currents, which in turn create magnetic fields.

This happens inside stars, in cosmic dust clouds and in pulsars dotted around the spiral arms of the Milky Way galaxy. Fluctuations in magnetic fields can fling charged particles into space, and when they collide with another magnetic field, the resulting interactions can have very powerful effects.

Earth has its own internal dynamo which turns the planet into an enormous bar magnet, and in early 2015 NASA launched four identical spacecraft as part of their Magnetospheric Multiscale Mission. Orbiting in a pyramid formation, they are gathering information about a phenomenon known as ‘magnetic reconnection’, where the two fields temporarily link up, transferring energy from one to the other.

 The Sun’s magnetic field

The Sun is made of plasma – a state of matter different from a solid, liquid or a gas. It is a sea of positive and negative particles, and as the particles move, they generate electrical currents, which create magnetic fields. The fusion reactions that power the Sun keep the plasma moving and as it spins on its axis, the charge particles are whipped up even more. Solar winds blowing away from the Sun’s surface also contribute to the changing magnetic fields, and occasionally pockets of extremely strong magnetism build up. This drives hot plasma away from the surface in arcs, forming sunspots or coronal mass ejections.

 

 A RECORDBREAKING MAGNETIC FIELD

The Los Alamos National Laboratory in New Mexico is home to a record-breaking electromagnet. Inside the Pulsed Field Facility is a £6.3-million ($10-million) electromagnet, capable of generating a field strength of up to 100 tesla (20,000 times stronger than the average fridge magnet). An electromagnet this powerful requires huge amounts of energy; this causes rapid heating, limiting the amount of time that the magnet can be used for. Most other magnets capable of achieving this kind of magnetic field are not able to withstand the strain, and break dramatically at the end of a single use. The magnet at the Pulsed Field Facility can be used over and over again. Each session lasts for just 15 milliseconds, but that gives scientists just enough time to perform their measurements. The magnet sits inside a tank of liquid nitrogen at -198.15 degrees Celsius (-324.67degrees Fahrenheit), helping to limit the amount that it heats up during the burst. It is then renewed and ready for another go within an hour.

 

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