When you push two magnets together, sometimes, they attract, and sometimes they repel. Every magnet has a north and a south pole. When the two poles facing each other are different, (i.e. north to south) magnets attract. However, when the two poles facing each other are the same, (i.e. north to north), the magnets repel. (The Super Science Book of Forces, p. 14) This concept can be illustrated to children in a few simple ways. If you have a set of BrioR trains accessible to you, they are very useful. Otherwise, bar magnets will work well. Prior to beginning this activity, go through your bar magnets, test and label all the poles. (You could also do this with your BrioR trains). Begin by allowing the children to attach some of the bar magnets or train cars together. Notice how sometimes they initially repel, but when you turn the magnet around, it attracts. If you do not have a large supply of bar magnets or BrioR train cars, you might want to consider implementing this activity as a demonstration with the entire class.
Now take two bar magnets or magnet wands and put them next to each other. See whether they attract or repel. If they attract turn one of them around so that like poles are together. Then they should repel. Raise the end of one magnet slowly so that it is a little bit above the same pole of the other magnet. The magnetic force should hold the raised magnet in the air. See illustration. (The Super Science Book of Forces, p. 15)
(figure available in print form)