The scientific laboratory is located in front of the cafeteria.

The preposition "in front of" is used to indicate the location of one thing in relation to another. In this sentence, the laboratory is located in a position that is physically closer to the observer than the cafeteria.

Here are some examples of the use of "in front of" in a sentence:

The store is located in front of the park. (商店位于公园前面。)
I always sit in front of the TV when I watch a movie. (当我看电影时，我总是坐在电视前面。)
He stood in front of the painting for a long time, admiring it. (他站在画前很长时间，赞美它。)