Chapter 7: Rani's Gift

Rani has brought a big colourful box. But how long is it? How heavy is it? Let us measure and find out!

What we'll do

• Compare which thing is longer or shorter.
• Use hand-spans, feet and strings to measure length.
• Compare which thing is heavier or lighter.
• Use a simple balance to weigh things.

The big idea

To find out how long something is, we measure it. Long ago, people did not have rulers. They used their own body , fingers, hand-spans, feet, arm-lengths. We can do the same!

A hand-span is the distance from the tip of your thumb to the tip of your little finger when you stretch your hand. We can ask: how many hand-spans long is the table? How many feet wide is the room?

For length, "longer" means more units; "shorter" means fewer units.

To find out how heavy a thing is, we use a balance. Place one object on each side. The side that goes down has the heavier thing. The side that goes up has the lighter thing. If both sides are equal, both things are equally heavy.

We can use small stones or rajma seeds as our "weight units". For example, "this pencil weighs 5 stones".

When two people measure the same table, they may not get the same number , because their hand-spans are different sizes! That is why grown-ups later use rulers and weighing machines that everyone agrees on.

Let's play!

Hand-span hunt. Measure your bed, your study table and one door using your hand-span. Write down each number.

Make your own balance. Tie a stick to a string in the middle so it hangs flat. Hang two paper cups, one on each side. Put a pencil in one cup, an eraser in the other. Which side goes down?

Heavier or lighter? Pick up two things , a book and a banana, a spoon and a slipper. Guess which is heavier. Check with your balance.

A small story

Rani's gift was a long ribbon. She wanted to know if it was longer than the one she already had. She placed both ribbons side by side, starting at the same edge. Her old ribbon ended at her shoulder. The new one went past her shoulder! "The new ribbon is longer," she said with a smile.

Quick check

1. Which is longer: your foot or your pencil?
2. Name two things that are heavier than a feather.
3. How many hand-spans is your study table?
4. On a balance, the heavier side goes __________ (up / down).
5. If two friends measure the same room in feet, will they always get the same number? Why or why not?

What did we learn?

• We measure length using hand-spans, feet or strings.
• We measure weight by comparing on a balance.
• "Longer" means more units; "heavier" means the side that goes down.