Vaccum is a space in which there is no matter hence there no pressure. There is no place on the earth which is completely empty. We can have only partial vacuum. It is a condition well below normal atmospheric pressure and is measured in units of pressure (the pascal). A vacuum can be created by removing air from a space using a vacuum pump.

1. Air exerts pressure in all the directions. The pressure exerted by air is called the air pressure, which is the thrust exerted by air per unit area.” The weight of the air acting on a unit surface area is called the atmospheric pressure.
2. Earth’s surface gets unevenly for many reasons. This unequal heating creates high and low air pressure zones. Thus to balance the pressure, the high-pressure air moves towards the low-pressure region which leads to the formation of winds.
3. Vacuum or partial vacuum is a  space in which there is no matter or in which the pressure is so low that any particles in the space do not affect any processes being carried on there. It is a condition well below normal atmospheric pressure and is measured in units of pressure (the pascal). A vacuum can be created by removing air from space using a vacuum pump or by reducing the pressure using a fast flow of fluid.
4. Suction pressure is a negative difference in pressure also called a vacuum is generated between two points which draws a gas or a liquid from a higher to a lower pressure state.

Inquiry: Explore Suction
a. Suction from a Straw

b. Suck from two straws at a time one inside the glass and another outside

c. Cut a Small hole at the top and try to drink