Magnificent Fun with Magnets

With little encouragement, children find many inventive activities that they can enjoy with magnets.

Magnets have a nice feel in the hand and seem to encourage children to discover at their own pace, taking on challenges and generally having creative fun while ‘learning by doing’. Children who are not engaged by other traditional activities seem to respond energetically and have great fun with magnets.

What are magnets?

Magnets are pieces of material that attract some metals. They can be of various types and strengths, and we usually say they have a distinct north and south pole - meaning two different ends. Magnetic materials attracted to magnets generally contain iron, often in the form of steel.

Magnets come in lots of interesting shapes and sizes - horse-shoe shaped magnets, rectangular bar magnets, round magnets (like marbles), and even ‘singing magnets’ (shaped like very small rugby balls).

Toys often incorporate magnets – for example, fishing rods, which pick up magnetic fish. We all have tiny magnets known as fridge magnets - the ornamental items printed with important phone numbers (the pizza shop for instance!), which we use to attach messages to our refrigerators or filing cabinets

Where are they used?

Magnets are vital parts of electric motors - in a complex interaction a moving magnet produces electricity and vice versa, a moving electric field produces magnetism. Then there are electromagnets in which electricity is used to switch magnetism on and off. You may have seen these working on cranes in metal scrap yards, where the magnetic force is used to lift and move old cars and parts, which are made of steel and iron.

There are many clever inventions which use magnets around the home - cupboard fasteners, doorbells, movable hooks, tools (for example  magnetic screw drivers which hold onto the metal screw) and refrigerator door seals.

Electrical appliances all round your house use magnets in their motors, as well as the television, computers (but not those monitors with newer plasma or LCD screens), sound speakers and microphones.

It is necessary to keep strong magnets away from credit cards or ATM cards, which have their own magnetic strips which need to be protected to function correctly. In a similar way powerful magnets can damage computer discs or digital storage devices and heart pacemakers.

Giant magnets are used in sophisticated engineering and scientific equipment, for example power stations, and the Australian synchrotron. This device has 28 huge seven tonne (7000kg) magnets central to its operation. Magnets are also used in MRI (magnetic resonance imaging) machines, which do medical scanning to reveal health problems.

Fun with magnets

The best fun is to use magnets as toys and these come in all shapes and sizes.

• Singing magnets - these interact to wiggle and crash together, and make various sounds. They can be used on tables or dropped onto the carpet. They are usually made of a synthetic iron compound (hematine), which can be formed into attractive shapes.

• Round magnets (about 2 cm diameter, the size of cherries) are very versatile. You can make snakes, bracelets, trains etc. See how many you can pick up in a chain.

• Horse shoe magnets - these are easy for small hands to manipulate. Pick up other magnets, small metal toys, nails, screws, paperclips etc.

• Rectangular bar magnets are the best for investigating the polar nature of magnets. Two of these magnets will repel or push each other away if you try to put the same polar ends near each other.

Any of these magnets can be used to create interesting patterns with metal spoons, bulldog clips and staples etc.

Move a strong magnet under a table spread with paperclips or nails or keys and watch the metal items move about. Paperclips themselves become temporary magnets if they are put in contact with a strong magnet.

Magnets act over a short distance and through paper and water. See another Learning by Doing article At the Beach http://www.parentbriefings.com.au/Page.aspx?ID=1441 for instructions on making magnetic jellyfish

Some common magic tricks rely on the use of hidden magnets in the magician or clown’s box of props. You can lift small metal objects magically without touching them.

What are magnets made of?

The earth itself acts like a magnet. People have been using magnets for thousands of years, initially as compasses in which a magnetic pointer interacts with the earth’s magnetic field to indicate the direction of north (now we use Global Positioning Systems (GPS), which work through signalling from satellites in space). The naturally occurring iron ore magnetite (or lodestone) has been known for thousands of years and its magnetic properties have always fascinated people.

Ceramic or Ferrite magnets are the most common magnets. Alnico magnets, made of aluminium, nickel and cobalt metals, need to be stored with an iron keeper to stop them losing their magnetism.

Strong ‘composite’ magnets (for example, neodymium alloys) made from rare earth elements are now being manufactured for use in cars, computers, mobile phones, DVD players and digital cameras.

Some of these engineered materials only show magnetic properties when they have been treated using electric currents.

Other interesting ideas about magnetism

• Bird and whale migration around the globe is suspected to be dependent on magnetic field sensing by these animals.
• Some medicinal properties have been attributed to magnets worn as bracelets etc.

Where can you buy magnets?

Hardware shops, gift shops and toy shops often have interesting magnets for sale.  For the best variety of specific types of magnets to purchase, look on the Internet under educational suppliers, or just magnets and you can order them online. They make terrific presents for all ages.

Important safety note: Toys containing magnets should usually have warning labels, as ingestion of magnets can be hazardous.

All activities described here are designed to be performed under the supervision of a responsible adult who is aware of any conditions, which might preclude the safe participation of the child.

Other Resources:

Look up magnet magic tricks on Google.

The Powerhouse Museum website http://www.powerhousemuseum.com has some interesting links about magnets

The Scienceworks Museum website also has fascinating magnet activities and articles, http://museumvictoria.com.au/scienceworks/

http://en.wikipedia.org/wiki/Australian_Synchrotron (About the Synchrotron - located near Monash University)

Article written by Kathy Andrewartha (B.App.Sci., M.Sc., B.A., Grad Dip. Info. Sci.). Kathy studied Biochemistry at Swinburne and La Trobe Universities and has worked on research topics involving both plants and animals. She enjoys teaching science at all levels. She particularly likes presenting science to young children, and is passionate about stimulating active learning and analytical thinking about scientific topics.