Measurement: Length, Weight & Capacity
Length (cm and m)
Length is how long something is. We measure short lengths in centimetres (cm) and longer ones in metres (m). 1 m = 100 cm. A pencil is about 15 cm; a door is about 2 m. We still compare with longer and shorter.
Example 1: Which unit suits the length of a classroom — cm or m?
Metres (m), because a classroom is long.
Example 2: A ribbon is 30 cm and another is 45 cm. Which is longer?
45 cm is longer.
Quick recap
- Short lengths: centimetres (cm). Long lengths: metres (m).
- 1 m = 100 cm.
✓ Quick check
Which is best measured in metres?
A cricket pitch is long, so metres.
1 metre = ___ centimetres?
1 m = 100 cm.
Weight (kg)
Weight tells how heavy something is. We measure it in kilograms (kg). A bag of rice may be 5 kg; an apple is much less than 1 kg. We compare with heavier and lighter and use a balance to weigh.
Example 1: Which is heavier — 2 kg of sugar or 5 kg of sugar?
5 kg is heavier.
Example 2: A watermelon is about 3 kg. Is an apple more or less than that?
Much less than 3 kg.
Quick recap
- Weight is measured in kilograms (kg).
- Compare with heavier / lighter; use a balance.
✓ Quick check
Which would weigh about 1 kg?
A packet of sugar is about 1 kg.
Add: 4 kg + 3 kg = ?
4 + 3 = 7 kg.
Capacity (litre)
Capacity is how much a container can hold. We measure liquids in litres (L). A water bottle may hold 1 litre; a bucket holds many litres; a spoon holds much less than a litre.
Example 1: Which holds about 1 litre?
A common water bottle.
Example 2: A bucket holds 8 L and is filled with two 4 L jugs. Does that fill it?
Yes — 4 + 4 = 8 L fills the bucket.
Quick recap
- Capacity is measured in litres (L).
- Buckets hold many litres; spoons hold very little.
✓ Quick check
Which is measured in litres?
Milk is a liquid, measured in litres.
A jug holds 2 L. How much do 3 such jugs hold?
3 × 2 = 6 L.
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