Class 1 — Mathematics

Measurement: Comparing Length and Weight

Class 1

✓By the end of this lesson students will be able to identify objects as 'long' or 'short'.
✓By the end of this lesson students will be able to compare two objects and tell which one is 'longer' and which one is 'shorter'.
✓By the end of this lesson students will be able to identify objects as 'heavy' or 'light'.
✓By the end of this lesson students will be able to compare two objects and tell which one is 'heavier' and which one is 'lighter'.

Key concepts

Long and Short

When we look at objects, some are spread out more from one end to the other. We say these objects are 'long'. Other objects are not spread out as much; we say these objects are 'short'. For example, a snake is long, and a worm is short. A pencil is long, and an eraser is short.

Heavy and Light

When we lift objects, some objects are harder to lift because they have more 'weight'. We say these objects are 'heavy'. Other objects are easy to lift because they have less 'weight'. We say these objects are 'light'. For example, a big stone is heavy, and a feather is light. A watermelon is heavy, and an apple is light.

Comparing

Comparing means looking at two or more things and finding out how they are different from each other. We can compare objects by their length (how long or short they are) or by their weight (how heavy or light they are). When we compare, we use words like 'longer than', 'shorter than', 'heavier than', or 'lighter than'.

Key facts to remember

1Length tells us how long or short an object is.
2Weight tells us how heavy or light an object is.
3When comparing length, we use words like 'longer' and 'shorter'.
4When comparing weight, we use words like 'heavier' and 'lighter'.
5A long object covers more distance from end to end.
6A heavy object is harder to lift than a light object.

Worked examples

Example 1

Look at the two pencils. Which pencil is longer?

IStep 1: Observe both pencils carefully.

IIStep 2: See which pencil extends further from one end to the other.

IIIStep 3: The pencil that covers more space in length is the longer one.

Answer

The first pencil is longer.

Imagine placing them side-by-side to see the difference clearly.

Example 2

Look at the book and the leaf. Which object is lighter?

IStep 1: Observe both the book and the leaf.

IIStep 2: Think about which one would be easier to lift or blow away.

IIIStep 3: The object that feels easier to lift or has less weight is the lighter one.

Answer

The leaf is lighter.

A leaf is very thin and airy, while a book has many pages and a cover.

Example 3

You have a school bag and a lunch box. Which one is heavier?

IStep 1: Think about a typical school bag filled with books and a lunch box with food.

IIStep 2: Imagine lifting both objects.

IIIStep 3: The object that requires more effort to lift or has more weight is the heavier one.

Answer

The school bag is heavier.

School bags usually carry many heavy items like textbooks and notebooks.

Common mistakes

✗Confusing 'long' with 'heavy' or 'short' with 'light'. These are different properties.
✗Not looking carefully at both objects when comparing their length.
✗Guessing the weight without thinking about the material or size of the object.
✗Thinking that a bigger object is always heavier (e.g., a big balloon is lighter than a small stone).

Exam tips

★Always look at the picture or read the question carefully to understand what you need to compare (length or weight).
★For length, imagine placing the objects next to each other to see which one extends further.
★For weight, think about real-life examples of the objects and which one feels harder to lift.
★Use the correct comparison words: 'longer', 'shorter', 'heavier', 'lighter'.

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