This document discusses atmospheric pressure and provides examples of how it is used. It defines atmospheric pressure as the weight of the air column over a unit area at the earth's surface. The density of air is greater near the surface and decreases with altitude. Standard atmospheric pressure is equivalent to a mercury column of 0.76 meters and is measured in bars using a barometer. Situations like drinking through a straw or using a syringe rely on differences in atmospheric pressure. The document suggests experiments for students to demonstrate atmospheric pressure concepts.

1. Atmospheric
Pressure

2. Introductory
Activity

3. • What happens to the pressure of the air inside?
• How is the pressure of air inside the bottle after
the mouth of the bottle is shut by the egg?
• What happens when the bottle gets cooled ?

4. When the paper burns the pressure
inside the bottle increases and some
air goes outside. Since the
atmospheric pressure outside the
bottle is greater than the pressure of
the air inside the bottle the egg slips
into the bottle.

5. Developmental
activity
• Where is the density of the atmospheric air
more?
• What is atmospheric pressure? How can it be
measured? What is its unit?

7. An envelope of air surrounds the earth. This is
earth’s atmosphere. The density of atmospheric air
near the surface of the earth is greater and it
decreases as we go up.
The weight of air column over the unit area
of earth’s surface is atmospheric pressure.

8. Situations where
atmospheric pressure is used

9. • Drinking juice using a
straw

10. • Medicines can be taken
from the bottle using a
filler

11. • Rubber Sucker

12. • Syringe

13. Explain the given situation based
on atmospheric pressure?
• Astronauts wear specially designed clothes
• As mountaineers climb higher altitudes there is
the possibility of nasal bleeding

14. Concluding
activity
• What is standard Atmospheric Pressure?
• Which instrument is used to measure Atmospheric
Pressure?

15. The weight of an air column above unit are
on the surface of earth at sea level is
considered as one atmospheric pressure.
This is equivalent to the weight of Mercury
column of height 0.76m and unit area of
1m2.This is standard atmospheric pressure.
The unit of atmospheric pressure is bar. The
instrument used to measure atmospheric
pressure is Barometer.

16. Review
Questions
• What is Atmospheric Pressure? Give its unit
• Explain the working of a Syringe with respect to
Atmospheric Pressure.
• What is Standard Atmospheric Pressure ?

17. Follow Up
Activity
• Find out more experiments to demonstrate
Atmospheric Pressure and note them in your
Science diary