Where Things Are, and Lines
Primary 1 · Mathematics
Where Things Are, and Lines
Lesson 3 of 3
12 min
Let's begin
Habimana finds a long rope at home.
He drops it on the ground. It lands in a bendy shape.
Then he pulls the two ends hard. Now the rope is straight.
Today you will name every kind of line.
Lay a stick on the ground. Look along it.
It does not bend. It does not turn.
That is a straight line.
The edge of your ruler is straight. So is the edge of your desk.
Now bend the rope slowly. Make no sharp points.
That is a curved line.
A banana has a curved edge. A road up a hill curves too.
Fold the rope this way, then that way. Make sharp points.
That is a zigzag line.
It goes, it turns sharply, it goes again.
The teeth of a saw make a zigzag.
| Line | What it does | Something like it |
|---|---|---|
| straight | never bends | the edge of a ruler |
| curved | bends softly | a banana |
| zigzag | turns sharply | the teeth of a saw |
Draw a big ring with chalk. Join the two ends.
Now put an ant in the middle. Can it walk out?
It must cross the chalk. So the line is closed.
Rub out a small part of the ring. Leave a gap.
Now the ant walks out through the gap.
So the line is open.
Careful! A round line is not always closed. Look for the gap first.
Keza draws a closed line on the floor. She puts three stones down.
One stone sits in the middle space. It is inside.
One stone sits away from the ring. It is outside.
One stone sits on the chalk itself. It is on the line.
A stone on the line is not inside. It is not outside either.
On the line is its own place. Give it its own name.
Sing the line song: straight, curved, zigzag.
Lines that are open and lines that are closed. Watch the first part.
Tip
Ask the ant
Can the ant walk out without crossing the line? Then the line is open.
Is the ant stuck in the middle? Then the line is closed.
Do each one, then tap Show answer to check.
You look along the edge of your ruler. What line is it?
Answer: straight. It has no bends at all.
A rope is laid down with sharp points, like saw teeth. What line is it?
Answer: zigzag. Sharp turns make a zigzag.
A chalk ring has a small gap in it. Is it open or closed?
Answer: open. The ant can walk out through the gap.
A stone sits on the chalk of a closed ring. Is the stone inside?
Answer: no. It is on the line. On the line is its own place.
Take a piece of string. Lay it straight, then curved, then zigzag.
Answer: one string makes all three. Say each name as you lay it.
What you learned today
All three are free to read. Read them with someone at home.
Zigoronzoye n'izigororotse is in Kinyarwanda, free to read from the Global Digital Library. On every page, say whether the thing you see is curved or straight.
Ni mu muhanda cyangwa ni mu kiraro? is also in Kinyarwanda, free to read from the Global Digital Library. Every page says where something is, so use your place words as you read.
Serpy, the Snake is in easy English, free to read from the Global Digital Library. Serpy cannot swim in a straight line. He goes zigzag, zigzag, zigzag.
Quick check
What kind of edge does a banana have?
