Question

24

Fig. 24.1 shows a liquid dropper used to draw a liquid from a bottle of
medicine. The squeeze bulb of the dropper is squeezed and then released
so that liquid from the bottle is sucked up into the tube of the dropper.

Explain how difference in air pressure enables liquid to be drawn into the
tube of the dropper.​

Answer 1

Answer: It is due to the low air pressure in the stopper and the atmospheric pressure.

Explanation: Whenever is there is a pressure, there must be a force exerted. Because,

Pressure = Force/ Area

So, when the bulb of the dropper is squeezed, the air pressure inside the dropper decreases because all the air is forced out.

When the dropper is placed in a liquid and the squeezed bulb is released, the air pressure outside the stopper surrounding the liquid becomes high and forces the liquid inside the dropper.

The rise of the liquid into the stopper is due to the atmospheric pressure.

This is similar to drinking liquids using a straw.