What does this below rebus puzzle mean?

A tree doubled in height each year until it reached its maximum height over the course of ten years. How many years did it take for the tree to reach half its maximum height?

After a heavy Thanksgiving meal, the night watchman went to work. In the morning, he told his boss he had dreamed that a saboteur planted a bomb in the factory and that he felt it was a warning. The boss promptly fired him. Worker confused, Why boss fire him?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

By moving just one matchstick, you need to make the below statement true. Can you do it?

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

Find the number of squares in the below picture

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.