Explain an activity to show that,during a free fall,heavier and lighter objects accelerate at the same rate.

(N/A) Take a sheet of paper and a stone. Drop them simultaneously from the first floor of a building. Observe whether both of them reach the ground simultaneously. We see that the paper reaches the ground a little later than the stone.
This happens because of air resistance. The air offers resistance due to friction to the motion of the falling objects. The resistance offered by air to the paper is more than the resistance offered to the stone due to its larger surface area. If we perform the experiment in a vacuum (a glass jar from which air has been removed),the paper and the stone will fall at the same rate and reach the ground at the same time. This proves that acceleration due to gravity $(g)$ is independent of the mass of the object.