Zero Conditional

Zero Conditional: certainty
We use the so-called zero conditional when the result of the condition is always true, like a scientific fact.
Take someice. Put it in a saucepan. Heat the saucepan. What happens? The ice melts (it becomes water). You would be surprised if it did not.
IF | condition |result |
  | present simple | present simple |
If | you heat ice | it melts. |
Notice that we are thinking about a result that is always true forthis condition. The result of the condition is an absolute certainty. We are not thinking about the future or the past, or even the present. We arethinking about a simple fact. We use the present simple tense to talk about the condition. We also use the present simple tense to talk about the result.The important thing about the zero conditional is that the condition always has the same result.
We can also use when instead of if, for example:When I get up late I miss my bus.
Look at some more examples in the tables below:
IF | condition | result |
  | present simple | present simple |If | I miss the 8 o'clock bus | I am late for work. |
If | I am late for work | my boss gets angry. |
If | people don't eat | they get hungry. |If | you heat ice | does it melt? |
 
result | IF | condition |
present simple |   | present simple |
I am late for work | if | I miss the 8o'clock bus. |
My boss gets angry | if | I am late for work. |
People get hungry | if | they don't eat. |
Does ice melt | if | you heat it? |