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Teacher cue
A2 · English Grammar

Zero
Conditional

If you heat water to 100°C, it boils.

if + present present simple
The idea

What is the zero conditional?

Used for things that are always true — scientific facts and general truths. It's not about a specific moment, but what always happens.

Examples

If you heat water to 100°C, it boils.

Plants die if they don't get enough water.

The structure

if + present simple

→ present simple

Both clauses, present simple. Always.

💡 Handy fact

If and when mean the same thing here

If you freeze water, it becomes ice. = When you freeze water, it becomes ice.
When I'm tired, I make mistakes. = If I'm tired, I make mistakes.
Don't confuse them

Zero vs first conditional

Zero — always true

If you touch fire, it burns you.

First — specific future

If you touch that fire, you will burn yourself.

In real sentences

See it in action

If it rains, the ground gets wet.
If you mix red and blue, you get purple.
Plants die if they don't get enough water.
⚠ Watch out

Common mistakes

If you will heat water, it boils.

If you heat water, it boils.

If it rains, the ground will get wet.

If it rains, the ground gets wet.

Plants dies if they don't get water.

Plants die if they don't get water.

If you mixes red and blue, you get purple.

If you mix red and blue, you get purple.

Now it's your turn

Let's
practice.

Say the answer out loud — then tap to check.

Practice 1
tap the blank to reveal

Fill the gap

If you heat ice, it(melt)
Plants(die)if they don't get sunlight.
If you(not / water)flowers, they wilt.
When metal gets hot, it(expand)
If you mix yellow and blue, you(get)green.
Practice 2
tap a sentence to reveal the error

Spot the mistake

If you heatA water toB one hundred degrees, it will boilC veryD quickly.

Cwill boil → boils

✓ zero conditional: present + present

IfA you mixB blue and yellow paint, you alwaysC would getD green.

Dwould get → get

✓ no would in the zero conditional

If water will freezeA, it expandsB andC can breakD the pipes in an old house.

AIf water will freeze → If water freezes

✓ no will in the if-clause

Practice 3
tap to reveal a model answer

Complete the sentence

If you don't sleep enough,
If you heat water to 100°C,
Plants grow well
When I'm tired,
Speak & write

Your turn

Answer with a general truth using if / when + present simple.

What happens if you don't drink water for a long time?
What happens when you mix two colors of your choice?
Complete: "If I'm hungry, I…"
Tell me a scientific fact using the zero conditional.
Recap

Remember this

Structure
if + present simple, present simple
Use
always true / general facts
If / when
interchangeable here
Never use
"will" in either clause

Both clauses present simple — it's always true, not a future possibility.

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