Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

A high school has a strange principal. On the first day, he has his students perform an odd opening day ceremony:

There are one thousand lockers and one thousand students in the school. The principal asks the first student to go to every locker and open it. Then he has the second student go to every second locker and close it. The third goes to every third locker and, if it is closed, he opens it, and if it is open, he closes it. The fourth student does this to every fourth locker, and so on. After the process is completed with the thousandth student, how many lockers are open?

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

Teacher ask the student

'Why are you standing on that chair in music class ?'.

what did student replied ?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

'S' refers to the number of seconds in a day and 'H' refers to the number of hours in ten years. Which quantity out of these two is greater?

In The 1st month of this year(the year 2013), I noticed that the date 13-1-13 (13 January 2013) is special.

This date is special as:

Date * Month = Year.

Can you figure out which year of this century has a maximum number of such dates?

There were five men at church, and it started raining while they were outside. The four that ran still got wet, but the one that was still stayed completely dry. Why did he stay dry?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?