Carts and Wheels

Questions with (*) sign are open ended questions.

Page 81

You must have seen many such round things around you. List some more in your notebook.

     Bangles, bowl, tyre, cup, globe, ball, plate, coin, sun, moon, etc.

Page 82

Have you ever gone to a bangle shop?

     Yes.

Take a wire and make a bangle for yourself. Can your madam or mother wear this bangle? 

     No, she can’t wear.

A bangle can be used to trace a circle. What are the other  things around you that you can use to trace a circle?

     We can use things like coins, plates, bowls to trace a circle.

(*) Trace a circle with the help of some of these things in your notebook or on the ground.

Which thing makes the smallest circle?

     Coins makes the smallest circle.

Which thing makes the biggest circle?

     Glass makes the biggest circle.

Page 83

Why do we make a circle in each of these games?

     A circle has no corners, so each child gets an equal opportunity.

What if a rectangle was made? Discuss.

     Some games are played by making rectangles. But some games like cricket requires circles so that boundaries are at equal distance.

Think of some other games you play by making circles.

     Some games that we play by making circles are musical chair, break the partner, pass the ball etc.

Page 84

Is any of these a good drawing of a circle? Discuss.

     No, none of these are a good drawing of a circle.

(*) Can you draw a circle on the floor with chalk? Try.

     Yes

(*) Also draw a circle in your notebook using a pencil.

(*) Look at the circles drawn by friends. Who has drawn the best circle?

Page 85

Can you also make a circle with a rope and nails like Ariba?

     Yes

(*) Do the activity in small groups. Each group should take a rope of a different length. See the circles made by different groups. Which group made the smallest circle ?

(*) How long was their rope?

      2 metre

Does longer rope make bigger circle?

     Yes.

Why is it so?

     Length of the rope makes the radius of the circle. Longer the radius bigger the circle.

(*) Which group made the smallest circle a rope?

(*) What was the radius of the smallest circle?

Page 86

Draw the radius of this bangle using a ruler. Measure the length of the radius.

     Radius = 3 cm.

Now see what your friends have drawn. Discuss the length of the radius they measured. Is it the same as yours?

     Yes, the radius drawn by all my friends is same.

Draw the radius of these circles.

Guess which circle has the longer radius.

     Radius of the blue circle is longer.

Measure the radius of both the circles using a ruler.

Write the length of their radius.

Radius of the green circle is 1 cm.

Radius of the blue circle is 2 cm.

Find out

Measure the radius of the wheels of a bicycle or a bullock-cart. You can use a thread or a measuring tape.

     Radius of the wheels of a bicycle is 30 cm.

     Radius of the wheels of a bullock-cart is 50 cm.

Are all the wheels of a bicycle or a bullock cart of the same radius?

      Yes, all the wheels of a bicycle or a bullock cart of the same radius.

Have you seen a tractor or a road roller?

     Yes.

Which is the biggest wheel you have ever seen?

     Giant wheel.

Are all wheels of a tractor or road roller of the same radius?

     No, the rear wheels of tractor and road roller are bigger.

Page 87

Lali and Kali are tied to a pole with ropes. Kali has a longer rope. Who can look for more grass to eat?

     Kali can look for more grass to eat as she has a longer rope.

Page 88

Is this circle better than the one you made earlier without a compass? Draw the radius of this circle and measure it.

     Yes, this circle is better than the one earlier made without a compass.

(*) Now you can make your own designs like Daljeet had made. How many did you make?

Page 89

Why did Naina get such a drawing? Discuss.

     Because Naina had changed the centre of the circle.

Can a circle have more than one centre?

     No, a circle has one and only one centre.

Page 90

Can you balance a plate on your finger?

     No, I can’t balance. It needs lots of practice to balance a plate on a finger.                    

You also try to balance a plate or a round lid on your finger. Where does it balance?

     A plate or a round lid can be balanced at the centre.

Page 93

Whose top will not spin at all?

     The tops made by Zakir and Naina will not spin at all.

Whose top will spin a little?

     The top made by Guddo will spin a little.

Whose top will spin the best?

     The top made by Appu will spin the best.

In whose top the stick is nearest to the centre?

     In the top made by Appu the stick is nearest to the centre

Make Your Own Top

You also make your own top and play this game.

To make the top spin well, where will you make the hole?

     To make the top spin well, we have to make the hole at the centre.

Points to remember.

A circle has one and only one centre.

A line segment joining the centre and any point on the circle is called as radius.

A circle has infinite number of radius.