Locker Puzzle (VIDEO!)

In this two-part video, students of St. Mark’s School first act out the famous locker puzzle:

100 lockers, all initially closed, lie along a corridor. Student 1 walks down the corridor and opens every locker. Then student 2 heads down and closes every second locker. Student 4 heads down next and changes the state of every third locker (closes it if is open, opens it if it is closed). She is followed by student 4 who changes every fourth locker, then student 5, student 6, and so on, all the way down to student 100 who touches every hundredth locker (namely, just the last one!).

What do the students see at the end of this result?

Video number 2 explains what we see in video number 1.

Video 1: The Demonstration
Video 2: The Explanation

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