How can you tell if a crate is explosive in the Testing Area?

Throughout the game, there are crates with yellow tape on them that you can break open to get an item. Prior to the Testing Area, I don't remember any of these boxes exploding after being broken open. Now, these boxes may explode after being broken.

Is there any way of knowing if they are explosive? They look like any of the other crates from what I can tell. I don't want to waste ammo shooting them from a distance. I figured since one can spot the trip wires for the other explosive traps in this area, that there is a way to identify explosive crates as well.

Solution 1:

You could hear the ticking sound if you go close to the crates if you increase the background volume. Other than that, in Ethan Must Die DLC, if the number of tapes on crate are more, then it contains explosive, but not sure if it is the same in normal game mode.