1, with a suction cup, suction of a smooth object, exhaust the air in the suction cup, the suction cup due to the role of atmospheric pressure tightly adhered to the object, the inference that the existence of air.

2, air is the medium of propagation of sound, will be an alarm clock in the bell-shaped hood, draw out the air in the hood, the alarm clock sound gradually reduced to inaudible, proving the existence of air.

3. The existence of air can be proved by filling a cylinder half full of water, blocking the mouth of the cylinder and placing it upside down, so that the water will not flow into the mouth of the cylinder.

4, find an empty beer bottle, the mouth of the bottle vertically down the water, into the water, until the water will be submerged in the entire bottle, this process if the control is very good, there will be no bubbles out of the water will not enter (pay attention to the vertical, if tilted, there will be bubbles), which means that the air exists so that the water can not enter.

Then slowly tilt the water bottle in the water, you will see bubbles coming out and water gradually entering the bottle, this is the air out and water entering to occupy the space of air.

5, weighing the mass, the use of an airtight container, sealed, weighing; and then in the sealed state of the air is sealed out of the air, and then weighing. The difference between the two weighings indicates that air is present. The amount of air extracted is the difference between the two weighings.

6, pressure measurement, the use of mercury column can be measured as the atmospheric pressure of 760mmHg, the use of the Madsenburg hemisphere test can prove the existence of atmospheric pressure. Change the temperature of the airtight combination, you can measure the change in pressure, proving the existence of air.