Lesson 13

• Economie
• Praktijkonderwijs
• Leerjaar 1

Observe and guess!

The picture is about ______________
and it is made up of _____________

Atmospheric pressure 

Leaarning objective : 

Define atmospheric pressure and related terms 

ATMOSPHERIC PRESSURE

1. The force exerted against the surface by continuous collision of gas molecules.

2. The weight of a column of air at a given place and time is called air pressure / atmospheric pressure.

Do you think atmospheric pressure is affecting us?

Yes

No

Observe and guess !

The left image is about __________
The right image is about ___________

ISOBARS AND BAROMETER

ISOBAR - Isobars are lines on a weather map joining together places of equal atmospheric pressure

BAROMETER - A barometer is a scientific instrument used to measure atmospheric pressure.

PRESSURE GRADIENT AND UNIT OF ATMOSPHERIC PRESSURE

PRESSURE GRADIENT 

Rate of change of pressure per unit horizontal distance.

atmospheric pressure units - mb/ pa/ mm Hg

atmospheric pressure units

learning objective 2 

Analyse the factors affecting atmospheric pressure 

Factors affecting atmospheric pressure

factors affecting atmospheric pressure 

1. Temperature 

2. Altitude

3. Water vapour / moisture 

4. Rotation of the Earth

Temperature

Altitude

Water vapour

Earth's rotation

Factors affecting Atmospheric pressure

• Altitude - pressure decreases with increase in altitude

• Temperature - pressure decreases with an increase in temperature

• Water Vapour - pressure decreases with an increase in water vapour

• Rotation - air moves from high pressure to low pressure.