Atmospheric Pressure

Give reasons for the following : 

Water does not run out of a dropper unless its rubber bulb is pressed.

Describe the crushing tin can experiment. What do you conclude from this experiment ?

Describe a simple experiment to illustrate that air exerts pressure.

What do you mean by atmospheric pressure?

The atmospheric pressure at sea level is nearly

The atmospheric pressure on earth surface is nearly _____.

(Choose from$10 \mathrm{Pa}$/${10}^5 \mathrm{Pa}$) 

The atmospheric pressure is nearly ${10}^5 \mathrm{Pa}$.

Higher we go, greater is the air pressure.

Gases exert pressure in all directions.

How does the atmospheric pressure change with altitude?

Give reason for the following :
A balloon collapses when air is removed from it.

Give reason for the following :
Two holes are made in a sealed oil tin to take out oil from it.

We do not feel uneasy even under the enormous atmospheric pressure. Give a reason.