I’m tall when I’m young, and I’m short when I’m old. What am I?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

How many sides does a circle have?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

During which month do people sleep the least?

Begin with a word, five letters to my name,
Remove the first and last but I am the same
Take out my middle and still, I remain.
What word am I?

I have no life, but I can die. What am I?

How many times can you subtract the number two from the number fifty?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

They do not possess flesh or feathers or scales or bone
But still, they are blessed with fingers and thumbs of their own.