Air – Basic 6 Basic Technology Lesson Note (Second Term)

Learning Objectives

By the end of the lesson, pupils should be able to:

1. Formulate a comprehensive definition of air
2. Write and demonstrate the properties of air
3. Explain air pressure and its uses
4. Demonstrate air pressure using simple objects

Content

Definition of Air Air is a mixture of invisible gases that surrounds the Earth, forming the atmosphere. It consists of:

• Nitrogen (78%)
• Oxygen (21%)
• Carbon dioxide (0.04%)
• Other gases including argon, neon, and water vapor (approximately 1%)

Properties of Air

1. Air Occupies Space
   1. Air molecules fill any available space
   2. Demonstration: Inverted glass in water with tissue paper
2. Air Has Mass and Weight
   1. Measurable mass despite being invisible
   2. Exerts pressure on all surfaces (101.3 kPa at sea level)
3. Air is Compressible
   1. Molecules can be pushed closer together
   2. Compressed air stores energy
4. Air Expands When Heated
   1. Hot air is less dense than cold air
   2. Creates convection currents
5. Air Exerts Pressure
   1. Acts equally in all directions
   2. Decreases with altitude

Applications of Air Pressure

1. Drinking straws
2. Syringes
3. Vacuum cleaners
4. Pneumatic systems
5. Aircraft flight
6. Weather forecasting
7. Tire inflation

Practical Experiments

1. Air Occupies Space: Glass, tissue, water bowl
2. Air Pressure: Crushing bottle with temperature change

Atmospheric Pressure: Water-filled glass with cardboard