Place one magnet on a (non-magnetic) surface and slowly move the other toward it. Depending on the orientation of the poles the stationary magnet will either begin to move away or toward the second magnet.
If the south pole of one magnet faces the north of the other the stationary magnet will move toward the second magnet. If the south of one faces the south of the other (or north faces north) the stationary magnet will move away from the second magnet.
It is also possible to investigate the relationship of the force's magnitude and distance between magnets. A crude set up would be to place one magnet on a weighing balance, with a pole facing upwards and then zero the scale. Next bring the second magnet above the first so that like poles are facing each other.
Using a rule to measure vertical separation move the second magnet toward the first and record the mass displayed on the weighing balance over a range of heights. Convert the mass values to force (w=mg) and plot them against height.
Also plot force (w) against