Magnetism



[|Magnetism] is a force that acts at a distance and is caused by a magnetic field. The magnetic force strongly attracts an opposite pole of another magnet and repels a like pole. The magnetic field is both similar and different than an electric field.

[|Magnetism] - the ability of certain objects to attract iron. Such objects are called magnets. Magnetism is also associated with electric currents. Magnets are widely used. All electric motors (and the generators that provide power for the motors) contain magnets, as do telephones and loudspeakers. The magnetic compass is a device used for finding direction. The earth itself is a huge magnet.

The [|history of magnetism] is long and mysterious. We have known about magnetism since at least the time of the Zhou Dynasty (1045-256 BC) in China when the properties of lodestone (magnetite) were explored as a means of direction-finding. But we still not know all there is to know about magnetism, even today.

[|2-D magnet] - For the first time, scientists have discovered magnetism in the 2-D world of monolayers, or materials that are formed by a single atomic layer. The findings demonstrate that magnetic properties can exist even in the 2-D realm -- opening a world of potential applications.

[|What is the magnetic field? (video)] - One of the earliest examples of recycling is scrap metal. If a building or a bridge is demolished, large quantities of metal structure inside can be saved and recycled. The metal is usually cut into pieces so it can be trucked away from the original site. Eventually the scrap will be taken to a facility that will melt it down and use it to make something new.
 * What's the problem?** - **Stuck on you**

Loading scarp metal is heavy work. Using a loader equipped with a powerful electromagnet, the work can be done more safely and quickly. The builders developed the equipment that is being used all over the world.
 * **Ask** - Scrap metal is usually delivered to the scrap yard on large pieces of different sizes and shapes. Most are really heavy. Many have jagged edges. The metal is usually sorted and eventually transported away for reprocessing. Working around these items is dangerous. How big are the pieces of metal? How much do they weigh?
 * **Imagine** - Being able to lift heavy pieces of metal without using lots of people is good both for productivity and for worker safety. How can magnetic properties of metal be used to assist in moving big chunks of metal?
 * **Plan** - Powerful electromagnets can be used to lift these heavy loads. How does an electromagnet work? How can it be fitted into the loading equipment?
 * **Create** - Loaders can be on wheels or rails, depending on its location and type of use. How much electricity is required for the electromagnet?
 * **Improve** - Some of loaders are used to load and unload train cars. Others are used to move and sort metal within the scrap yard. How can a loader be customized for the type of use?


 * That's engineering**
 * attraction
 * repulsion

> magnetic force, poles, attraction, repulsion, demagnetize, magnetize,
 * Engineering ideas**

Now it is your turn. Here are some challenges for you to work on...
 * Do it**
 * [|Faraday's Electromagnetic Lab] - simulates some basic experiments in magnetism and magnetic induction.
 * design an experiment to demonstrate the properties of magnets
 * create a work of art that incorporates the concept of magnetism
 * [|Magnets] - matching puzzle


 * Learn more...**
 * [|What is the magnetic field?]
 * [|Magnetism]
 * [|Magnetism]
 * [|NASA - Magnetism] - Magnetism is a simple force, but many of its properties seem mysterious!
 * [|Friction]
 * [|Exploratorium - Magnetism]

..r1