Zero Conditional

The zero conditional is used when describing situations which have automatic or habitual results. Using this conditional suggests that we are 100% sure of the result.

• If you heat ice, it melts. (will melt is also possible)
• If there is a shortage of any product, prices of that product go up.
• My parents get angry if I come home late.

As you can see, both the main clause and the if-clause are in the Present Simple.

The zero conditional is often used to give instructions:

• Press the button if you want a receipt.
• If you want to leave a message, speak after the tone.