The activity is as follows:Take a small aluminium rod AB. Using two connecting wires suspend it horizontally from a stand, as shown in figure given below.

Place a strong horse-shoe magnet in such a way that the rod lies between the two poles with the magnetic field directed upwards. For this put the North Pole of the magnet vertically below and South Pole vertically above the aluminium rod.
Connect the aluminium rod in series with a battery, a key and a rheostat.
Now pass a current through the aluminium rod from end B to end A.
It is observed that the rod is displaced towards the left and rod gets displaced.
Reverse the direction of current flowing through the rod and observe the direction of its displacement. It is now towards the right.