Why it happens: One half turn takes Reema to the opposite side of the circle. The second half turn takes her over the remaining half. Two halves make one whole — so she is back exactly where she began, facing the same way as at the start.
Check it yourself: Stand up. Turn to face the back wall (half turn). Turn the same way again. You are facing the front wall once more — a full turn.
Q2.
What happens if she takes 2 quarter turns in the same direction? It is like a ______ turn.
Two quarter turns, one after the other, add up to a half turn.
Why it happens: A full turn is cut into 4 equal quarters. Taking 2 of those 4 quarters is taking 2/4 of the circle — and 2/4 is the same as 1/2.
Q3.
What happens if she takes 4 quarter turns in the same direction? It is like a ____ turn.
Answer
It is like a full turn.
1/4 + 1/4 + 1/4 + 1/4 = 4/4 turn = 1 full turn
Four quarter turns take you right round the circle — back to the start.
Why it happens: Four quarters make one whole, just as four quarter-chapatis make one full chapati. So Reema ends up facing exactly the way she started.
Tip: Remember these three by heart — 2 quarters = 1 half, 4 quarters = 1 full, 2 halves = 1 full.
Q4.
Write some of the everyday objects that involve turns. For example, taps, __________, __________, __________, __________, and __________.
Answer
Any five of these will fill the blanks:
taps, door handles, bottle lids, ceiling fans, clock hands, and bicycle wheels
Many more you can add:
a key in a lock
the steering wheel of a car or an auto
a screwdriver and a screw
a mixer or grinder
a potter’s wheel
a spinning top (lattu)
the pages of a book, as you turn them
a merry-go-round or a giant wheel at the mela
Try This: Walk around your house for five minutes and write down every single thing you find that turns. Most children find more than fifteen.
Q5.
What is the maximum possible turn in each of these cases? Check and tick. (Clothes clip, Door with hinge, Tongs, Scissors, File cover)
Answer
Open each thing as wide as it will go, and compare that opening with a quarter turn — that is, with the corner of your notebook.
Object
Less than a 1/4 turn
1/4 turn
More than a 1/4 turn
Clothes clip
✓
Door with hinge
✓
Tongs
✓
Scissors
✓
File cover
✓
Here is the reason for each one.
Clothes clip. Press it hard — the two ends open only a small gap. Far less than the corner of your notebook.
Door with hinge. Push it right back till it touches the wall. That is much wider than a corner — more than a quarter turn.
Tongs (chimta). They open a little, to pick up a roti. Less than a quarter turn.
Scissors. Open them fully — the blades make a narrow V. Still less than a quarter turn.
File cover. Open it right out so it lies flat on the table. That is a half turn — more than a quarter turn.
Check it yourself: Hold the corner of your notebook against the opening. If the opening is narrower than the corner, it is less than a quarter turn. If it is wider, it is more.
Q6.
Do any of the above objects make a half turn? Write their names below—
Answer
Yes — the file cover, and a door.
File cover: open it out completely and it lies flat. The two halves are now in one straight line. That is exactly a half turn.
Door: a door that swings right back and touches the wall behind it has also made a half turn.
A file cover opened flat: the front cover has turned half a circle.
Why it happens: When the two parts lie in one straight line, the moving part has gone from one side right across to the other side — half of a full circle.
Q7.
Do any of the above objects make a full turn? Write their names below—
Answer
No. None of these five objects makes a full turn.
Each one is joined at a hinge or a joint, and the hinge stops it before it can go all the way round.
Did you know? A spiral-bound notebook is the one cover that can go all the way round — you can fold its front cover right behind the back cover. That is a full turn. Things that really do make full turns are a tap handle, a fan, a wheel and a clock hand.
Q8.
Pragya joined a green and yellow straw with paper clips. She holds the green straw steady and turns the yellow straw around. Observe different turns of the yellow straw.
Answer
Do this yourself with two straws (or two thin sticks) and a paper clip.
Join the two straws at one end with a paper clip. The clip is the corner.
Hold the green straw still on the table. Do not move it at all.
Turn only the yellow straw, slowly, and stop at different places.
Each time you stop, look at the opening between the two straws.
This is what you will see, in order:
Turn of the yellow straw
What the opening looks like
Name of the angle
a small turn
a narrow opening
acute angle
1/4 turn
a square corner
right angle
between 1/4 and 1/2
a wide opening
obtuse angle
1/2 turn
the two straws in one straight line
straight angle
3/4 turn
more than a straight line
more than a straight angle
full turn
the yellow straw is back on the green one
full turn
The green straw stays fixed. The yellow straw turns — here it has made a quarter turn, a right angle.
Sample answer: “When I turn the yellow straw a little, I get an acute angle. At a quarter turn I get a right angle. Past that I get an obtuse angle, and at a half turn the two straws lie in one straight line.”