[Grammar] What happens if I press this button?

[kadioguy]

What happens if I press this button?

https://www.macmillandictionary.com/dictionary/british/happen
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a. What happens if I press this button?
b. What will happen if I press this button?

What is the difference in meaning between them?

 

[J&K Tutoring]

They have the same meaning.

a. This is a general statement of what always happens at the press of this particular button. Present tense is appropriate.
b. This asks about a future result after pressing the button.

Both consider the result of pressing a button which we presume activates some mechanical devise and always results in the same outcome.

 

[jutfrank]

It may be useful to understand the difference in terms of general/specific.

a. is a about a general outcome. The use of the present simple shows that the speaker assumes that the same thing happens every time. In other words: What always happens?

b. is about a specific outcome. The use of will shows that the speaker is asking for a prediction. In other words: What will happen on this occasion? It is different from a. in that it does not presuppose that the same thing happens every time. (However, that's not to say that the speaker definitely doesn't think that the same thing happens every time.)

Practically speaking, they are are both very likely to be used in the same way.

 

[Tdol]

What is the difference in meaning between them?

Nothing much in many contexts.