SCIENCE - FORM 2
The Kinetic theory of gases
1. The kinetic theory of gases states that particles in a matter are always moving or vibrating. Gas
particles in a matter are always moving or vibrating. Gas particles in a container collide with each other and with the walls of the container all the time.
2. Air or gases are matter that have particles that move randomly in all directions.
Producing air pressure
1. Air has mass. Therefore air has weight.
2. Air has particles that are continually moving and colliding with things on Earth. These collisions
produce air pressure.
3. Air presses down on all things in the Earth's surface. The pressure exerted by air is known as air
pressure or atmospheric pressure.
4. The features of air pressure are :
(a) acts in all direction
(b) changes from one place to another
(c) decreases the higher you go above ground level. This feature exists because at high place, the
amount on air decreases. This explains why the air pressure on the top of a mountain is lower
that at the foot of the mountain.
Factors that influence air pressure
1. Air is a mixture of gases made up of practicles that move randomly in all directions.
2. Air pressure increases when air is heated. This is because the air particles obtain more energy and
collide with the walls of the container more vigorously.
3. When air compressed, air particles collide with the walls of the container more frequently and rhis
makes the air pressure increase.
4. The increasing volume of gas in the container increases air pressure.
5. A brief explanation on the factors that influence air pressure in a closed container is given on the
APPLYING THE PRINCIPLE OF AIR PRESSURE IN OUR DAILY LIVES
1. There are many tools in everyday life that function based on the principle of air pressure.
2. Below are some tools that depend on air pressure to operate.
3. The principal of air pressure can be used to solve problems in our everyday life such as clearing a
clogged pipe using a suction pump and pouring condensed milk from a can.
Gas under high pressure
1. When a gas is placed under a sufficiently high pressure or is cooled sufficiently, it condenses and
becomes a liquid.
2. The liquid will become a gas again when the pressure is released.
3. This property is used to store gases under high pressure in gas tanks and aerosol cans.
Safety measures when using gas under high pressure
The following safety measures must be followed when using gases under high pressure.
(a) Place the gas tank upright.
(b) Keep the gas tank away from heat sources (fire) or sunlight.
(c) Light a match forst before turning on the gas.
(d) do not store the gas tank in an enclosed space.
(e) Do not throw aerosol cans into a fire as they will explode.
(f) Turn off the gas supply when you do not need it any longer.
(g) Check to ensure that all mgas tubes and connections are tight and do not leak.
(h) Used a soap solution to cheak for leaks along gas tubes and connections.