# Magnetism and Electromagnetism

## Georg Ohm

1. His focus of study was electricity.2. He discovered the law that current flow through a conductor is directionally proportional to voltage and inversely proportional to resistance He discovered this by using different types of wire and seeing that thick wires carried more current than thin, helping him write his law. 3. It helped scientists to calculate the amount of current, voltage, and resistance, and establishing the science of eletrical engineering.  4. The multimeter can measure resistance in ohms as well as voltage and current.

## Charles-Augustin de Coulomb

1. His focus of research was the law of electrical repulsions. 2. He came up with Coulomb’s law that says the force between two electrical charges is proportional to the product of the charges and inversely proportional to the square of the distance between them. He discovered this when he was attempting to investigate the law of electricity. 3. He established the inverse square law of attraction  and repulsion of similar and different magnetic poles which became the base for the mathematical theory of magnetic forces developed by Simeon-Denis Poisson. 4. It is used to determine the force between two electrons and is usually used to calculate physics word problems.

## Joseph Henry

1.  His main focus of study was electromagnets. 2. He discovered electromagnetic induction because he was the first to turn in his results. He discovered this when he was making an electromagnet for Yale College that supported 2,088 pounds also setting a world record. He also created the first electric motor. 3. While helping Samuel FB Morse with the telegraph he discovered many principals of electricity and also discovered that by insulating the wire and wrapping it around the core greatly increased the power of the electromagnet. 4. Generators and Motors are modern uses for electromagnets and electromagnetic induction.

## Heinrich Hertz

1.)   His main focus of study was electromagnetic waves. 2. When showing his class that reflection and rarefaction were the same as the ones of light and heat waves he discovered that light and heat are electromagnetic radiations. 3. He began to research rarefied gases. 4. One example would be light bulbs because light bulbs use hertz.

## Aurora Borealis

This occurs when highly charged electrons from solar winds that interact with elements in the Earths atmosphere. When they enter the Earths atmosphere, they follow the magnetic force created by the Earths core and flow through the magnetosphere.

## Electromagnetic Induction

Production of an electric current by changing the magnetic field closed by an electrical circuit. The most common use of electromagnetic induction is in the electric generator.

## 5 ways humans have used electromagnetism to improve our lives:

1) Electromagnetics control the switches in relays, which help us use telephones and computers. 2) It can help lift heavy objects that are electromagnet like cars in a junk yard. 3) They are used to in security systems in our homes and buildings. 4) Electromagnets are also found in the propulsion system of space crafts whcih help us get to space. 5) Electromagnets are also used in transportation like trains, that levitate the cars.

## Inventions using magnetic force

Compass: A compass consists of a small, lightweight magnet balanced on an almost frictionless point. The south end points at the North and the north end points at the South. So the needle technically points North.

Credit Cards: Credit Cards are capable of storing data by modifying the magnetism of tiny iron-based magnetic particles on a band of magnetic material on the card.

Security Devices: In this technology, a magnetic, iron-containing strip with an adhesive layer is attached to the items. It is deactivated by a scanner that uses a specific highly intense magnetic field.

MRI: MRI machines use a superconducting magnet, which consists of many coils or windings of wire through which a current of electricity is passed, creating a magnetic field.

Refrigerator Magnets: When a magnet is placed on the fridge door, that section of the refrigerator covered by the magnet actually rearranges on an atomic level to become another magnet
Magnetic recording media: Magnetic storage uses different patterns of magnets in a magnetized material to store data.

TV: In a TV's cathode ray tube, the stream of electrons is focused by a focusing anode into a tight beam and then accelerated by an accelerating anode.

Speaker: . It has a diaphragm that is vibrated by sound waves in an area. The signal from a microphone gets encoded on a tape or CD as an electrical signal. When you play this signal back on your stereo, the amplifier sends it to the speaker, which re-interprets it into physical vibrations.

Microphones: Microphones convert sound waves into audio signal. When the diaphragm vibrates, it causes other components in the microphone to vibrate. These vibrations are converted into an electrical current which becomes the audio signal.

Scrap metal crane: A magnetic crane works by picking an object using the magnetic pull of the magnet. Its capacity to pick higher loads depends upon the power of the magnet.

## Work Cited

“George Simon.” Britannica School. Encyclopedia. Britannica Inc., 2013. Web. 20 March 2013. http://school-preview.eb.com/levels/high/article/56864

“Charles-Augustin de Coulomb.” Britannica School. Encyclopedia. Britannica Inc., 2013. Web. 20 March 2013. < http://school-preview.eb.com/levels/high/article/26555>

"Britannica School." Britannica School. N.p., n.d. Web. 22 Mar. 2013.

"Britannica School." Britannica School. N.p., n.d. Web. 22 Mar. 2013.

http://en.wikipedia.org/wiki/Magnetic_stripe_card