The zero conditional describes sentences that use the simple present tense in both clauses to express general truths and scientific facts. The order of the clauses can be reversed without changing the meaning. "If" can be replaced with "when" as both indicate general situations that are real and possible. Examples given are "If you freeze water, it becomes a solid", "Plants die if they do not get enough water", and "If my husband has a cold, I catch it usually".

1.  
The Zero
Condicional
Paula Jimena Mancera Ramírez

2.  In the ( "zero conditional " ) conditional sentences type 0 tense in
both propositions is the "simple present" .
 As with all conditional sentences , the order of the propositions is
not fixed. It may be necessary to change the pronouns and
punctuation by reversing the order of the proposals but the
meaning of the sentence will not change. In the prayers of
"conditional zero " you can replace "if " to " when" without
affecting the meaning , since both terms are used to express
general facts .

3.  The conditional type 0 is used to make statements about
the real world and usually refers to general facts we take
for certain , as scientific facts . In these prayers the time
frame is now or ever and the situation is real and possible.
 EXAMPLES
 If you freeze water , it Becomes a solid .
 Plants die if They do not get enough water .
 If my husband has a cold , I catch it Usually .