How to design experiments in physics to prove that air resistance affects the falling of objects?

How to design experiments in physics to prove that air resistance affects the falling of objects?

Parachute tools are OK. In fact, in the real world, all of them are real answers. It's just a question of analysis angle

In the experiment of free falling body, why choose heavy objects with high density to reduce the air resistance

To be exact: reduce the effect of air resistance
Because the air resistance is mainly related to the velocity and the shape of the object, the resistance of the object with higher density is the same as that of the object with smaller density. When the gravity is large enough, the influence of the resistance can be ignored

How to prove that the density of the gas is higher or lower than that of air?

Use the same method to collect two tubes of gas at the same time, one tube mouth up and one tube mouth down. After a period of time, detect the gas at the same time, observe the phenomenon, and compare the degree of gas leakage of the two tubes. When the mouth is up, the density of gas with small loss is larger than that of air, otherwise it is smaller