Research how magnetic forces work. Write a paragraph explaining that magnetic objects emit a magnetic field created by the movement of electrical ions that sends positive charges to one end (north pole)and negative charges to the other (south pole) giving the magnet the power of attraction. If you put two like-charged poles together, the lines of force coming from the magnet will deflect one another, pushing the magnets apart. However, if you put a positive and negative pole next to each other, the lines of force align and attract one another.
A good science experiment starts with a testable question. Pose a question such as "Which types of metal objects do magnets attract?" or "Which objects have the iron content to attract magnets?" Predict the results for each test object and record your hypotheses. For example, paper clips and pennies will be magnetic but tin cans and mom's earrings will not."
Collect objects of different metallic content. Some possibilities are a tin can, a soda can; copper, iron, steel and zinc nails and screws; paper clips, safety pins, thumb tacks, silver and copper coins from different countries and time periods, bottle and jar lids, a ring,earring or, aluminum foil, toy cars and trucks or silverware. Consider comparing the magnetism of permanent magnets (ceramic or ferrite, alnico, neodymium iron boron and Samarium cobalt); temporary magnets (made by attaching a paper clip or iron nail to a strong magnet thereby magnetizing it); and electromagnets (built from copper wire, a 6-volt battery and an iron nail). You may also test the magnetic properties of different magnet shapes such as bars, rings, discs and horseshoes.
The test itself is as simple as passing a magnet over each test item. Magnetism is a force that pulls on nearby objects. An item that is attracted to the magnet will exhibit movement or attach itself to the magnet as it passes over depending on magnet strength and distance from the magnetic field. Record the reaction of each item when exposed to the magnet: no reaction, moves or wiggles in some fashion while in the magnetic field or jumps onto the magnet. From this you should be able to infer the relative iron content that makes materials and objects magnetic. Compare results with the hypotheses and write a paragraph explaining the differences in metal content that make one object more or less magnetic than another.
Create a poster board or three-panel science fair display board that explains the history and science of magnetism, your testing procedure and results. Take pictures of your experiment and include them on your display for visual interest. For a hands-on demonstration, display a magnet and collection of items and let visitors try to find the magnetic items on their own.