Liquid Pouring: Capacity

Today's big idea

One litre and 1000 millilitres are the same amount wearing two different labels.

Jug markings often show both, so read the one your question is written in.

How it works

👀 What's going on?

A water bottle holds about 500 mL. A bucket holds about 5 L. Capacity is how much liquid a container can take, and only two units are needed for it.

💡 Here's the trick

Look at the beaker above. Its top line reads 1000 mL, and the very same line is labelled 1 L on the left. So 1 L and 1000 mL name one amount. The water rests on the 750 mL line, which the beaker also calls three quarters of a litre. Going from L to mL you multiply by 1000, and coming back you divide by 1000.

🪄 How to do it

1.Read the level on the beaker above, and note its unit.
2.To turn L into mL, multiply by 1000.
3.To turn mL into L, divide by 1000 and keep the leftover as mL.

✍️ Try it

1.A jug holds 4 L of squash. How many mL is that?
2.A tank holds 3250 mL. Write that amount in litres and millilitres.

The jug is 4 × 1000 = 4000 mL. The tank splits instead: 3250 mL holds 3 whole litres, and 250 mL is left over, so it is 3 L 250 mL.

⚠️ Watch out

You might be thinking 1 L 50 mL is 1500 mL, because 50 looks like half of something. It is not. 1 L 50 mL is 1000 + 50 = 1050 mL. Pad the small part out to three digits and the mistake disappears.

🌟 Why this matters

Capacity turns up whenever you cook, share a drink, or fill a bottle for school. A recipe wanting 1 L 500 mL of stock is really asking for three 500 mL cartons. Reading the label and the jug in the same unit is how you know you have enough.
Exam tip: Turn everything into mL before you add or subtract, then change the answer back.

Watch me solve one

Quanta solves it

“Watch how I think through one of these — then you try.”

THE PROBLEM

“A jug has 2 L 350 mL of juice. How many mL is that?”

1
Recall the conversion
1 L = 1,000 mL. 💧
2
Convert the litres
2 L = 2 × 1,000 = 2,000 mL.
3
Add the leftover mL
2,000 + 350 = 2,350
4
Total ✓
2 L 350 mL = 2,350 mL

Now you try one — same steps, different story 👇

See it in action

⚡ Time to play!

Pour 250 mL at a time. Fill the jug up to the 750 mL line.

CAPACITY · ROUND 1 OF 3

750

POURED

0 mL

Quick check

✅ VERIFICATION

A jug already holds 500 mL. How much more juice is needed to fill it to 2 L?

⚡ Finish the activity above first to answer.

Keep going!

Up next: Weighing Scale

1 kg = 1000 g. Multiply or divide by 1000.

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