Air in motion

Back to: Basic Science Primary 3

Welcome to class.

The earth is covered by thin layer of mixed gases called the atmosphere. The air is a mixture of several gases, oxygen, nitrogen, water vapour, and traces of carbon dioxide, argon, dust etc. it cannot be seen, but can be felt in so many ways. Air has weight; it can occupy space, and also exert pressure on objects. This makes us feel the presence of air around us.

Since air can occupy space. It can be used to fill balloon, football, mattress, tyres, etc. Air can do work because it has no weight. This is done by carrying lite, papers, parachute, etc. from one place to the other.

 PROPERTIES OF AIR

1. Air has pressure
2. Air has density
3. Air can be compressed
4. Air is invisible but can be felt
5. Air occupies space
6. Pure air is odourless.

IMPORTANCE OF AIR

1. It can be used to sail boat
2. It helps to dry wet clothes
3. It helps to rotate windmill to generate electricity
4. It is one of the sources of energy (i.e. wind energy)
5. It helps to move oxygen around so that we can have constant amount in the cycle.
6. Plants uses air to grow and make their own food.
7. Thanks to air, human and all living things have oxygen to breathe.
8.   Birds use air to fly.
9. we inflate balloons and tyres with air
10. Without air, afire will not burn.

WIND

Wind is air in motion. It flows from a high pressure area to a low pressure area as a result of convection. Wind can displace objects. i.e, carry them from one place to another. Air in motion makes our body feel cool when it blows on us. Energy obtained from wind is called a wind energy.

EFFECTS OF WIND

Wind has a lot of effects on objects and human. These effects include:

1. It makes our body feel cool when blown on us.
2. It carries dusts when its intensity rises (e.g, when it is about to rain)
3. Wind carries the leaves on trees (e.g when it is about to rain)

HARMFUL EFFECTS OF WIND

1. Wind transports harmful substances, such as acid fumes, carbon monoxide, dust which may be dangerous to our health.
2. Wind can cause eye blindness if it is uncontrolled.
3. Air – borne disease, such as Meningitis, Chicken pox, Tuberculosis (TB) and influenza, are easily transmitted through wind.
4. Wind can cause natural disaster, such as cyclone, tornado, typhoons, hurricane, etc.

Evaluation

1. What is Air?
2. Mention 3 properties of Air?
3. Define Wind?
4. Mention 3 harmful effects of wind
5. Which of the following is not an airborne disease? (a) meningitis (b) chicken pox (c) Tuberculosis (d) HIV/AIDS
6. Which of these objects cannot be carried by wind? (a) paper (b) Stone (c) Nylon
7. Energy obtained from air is? —— (a) wind energy (b) sun energy (d) light energy.
8. Which of the following is not a property of air (a) air is weightless (b) it can exert pressure (c) air has weigh (d) air occupies space

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