Water, Air and Weather
Primary 2 · Science and Elementary Technology
Water, Air and Weather
Lesson 3 of 3
14 min
Let's begin
At break, Mutesi puts her paper down on the step. She turns around for one second.
Whoosh! The paper is running away across the yard. She chases it.
Nobody threw that paper. Nobody touched it. So what pushed it?
Something you cannot see. Today you will catch it.
You cannot see air. So let us feel it instead. Try all three tests.
Test 1: the book fan. Hold your exercise book flat. Fan it fast in front of your face.
Something cool pushes your cheek. Now look at the space in front of you. You see nothing there. But you felt it. That something is air.
Test 2: the bag. Hold a plastic bag open. Swing it fast through the room, then twist the top shut. The bag is now fat and round, like a small pillow.
The bag caught something. It caught air. Air was standing in the room all along.
Test 3: the bubbles. Take a bottle with nothing in it. Push it straight down into a basin of water, with the open top facing down.
Look inside. The water does not go up into the bottle! Something is already in there, holding the water out.
Now tip the bottle over on its side. Bubbles come rushing out! And as they leave, the water runs in to take their place.
Think hard about that. Bubbles cannot come out of a bottle with nothing inside. So the bottle was never really empty. It was full of air.
Air is everywhere. In the room, in the bag, in the bottle you called empty. And in your chest, right now.
When air stands still, you hardly notice it. When air moves, you feel it at once.
Moving air has a name. We call it wind.
You cannot see the wind. But you can always see what the wind is doing:
So Mutesi's paper was pushed by the wind. Mystery solved.
Here is a little tool you can make. Tie a thin strip of paper to the end of a stick. Hold it up high, outside.
Now you can see the wind, because you made something for the wind to push.
Weather is what the sky and the air are doing outside, right now.
Sunny. The sky is bright and blue. You feel warm, or hot. Look at the ground: your shadow is dark and sharp. The paths are dry and dusty. Washing dries quickly.
Cloudy. Grey or white clouds cover the sun. The day is dull and cooler. Your shadow goes faint, or you cannot find it at all. Clouds are made of very tiny drops of water, floating high up.
Rainy. The clouds get dark and heavy. Water falls from them and drums on the roof. Puddles fill the yard, and the path turns to mud. Why does it rain? When the tiny drops in a cloud join together, they get heavy. Too heavy to float. So down they come.
Windy. The air is moving. Trees bend, dust flies, your wind flag streams out straight, and you hold on to your hat.
One thing to notice: windy can join the others. A day can be sunny and windy. A day can be rainy and windy. Wind can come with any sky.
A chart is how a scientist remembers. Every morning, look outside and draw one picture for the day: a sun, a cloud, some rain, or a bent tree for wind.
Here is Keza's chart for one school week.
| Day | Weather |
|---|---|
| Monday | Sunny |
| Tuesday | Sunny |
| Wednesday | Rainy |
| Thursday | Cloudy |
| Friday | Sunny |
Now count each kind of weather, one row at a time.
Check your counting: 3 and 1 and 1 make 5. There are 5 school days in the week. The counting is right.
Which weather came most often? Sunny, with 3 days. It is the biggest number.
Which came least often? Rainy and cloudy, with only 1 day each.
Now you can say something a scientist would say: "This week was mostly sunny." And you know it, because you wrote it down.
Tip
Every morning, read the weather in three moves: sky, shadow, skin.
Sky - look up. Sun or cloud? Rain?
Shadow - look down. Sharp shadow means sun.
Skin - stand still. Do you feel the air pushing? That is wind.
Warning
Never put a plastic bag over your face or your head, not even for a second. You need air to breathe.
Do the bag test with your hands only, far away from your face.
Answer first. Then check underneath.
You push an empty bottle upside down into a basin of water. The water will not go in. Then you tip the bottle and bubbles come rushing out. What was really inside the bottle?
Answer: air. The air was holding the water out. Bubbles cannot come out of a bottle with nothing inside, so the bottle was never really empty.
Gatete cannot see the wind. Name two things he can look at to know that the wind is blowing.
Answer: many answers are right. The washing flapping on the line, dust or leaves moving, trees bending, a paper running away, his wind flag flying out straight.
The sky is bright, your shadow is dark and sharp, and the path is dusty. What is the weather?
Answer: sunny. A sharp shadow is the clue - only the strong sun makes a shadow like that.
Here is Umutoni's chart: Monday rainy, Tuesday rainy, Wednesday cloudy, Thursday rainy, Friday sunny. How many rainy days?
Answer: 3. Count them: Monday, Tuesday, Thursday. Check the total: 3 rainy and 1 cloudy and 1 sunny make 5 days. Correct.
Can a day be sunny and windy at the same time?
Answer: yes. Wind can come with any sky. A day can be sunny and windy, or rainy and windy.
Note
What you learned today:
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