What has many keys but can’t open a single lock?

The more of this there is, the less you see. What is it?

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

A wooden log balances equally on the scales when weighed with three-quarters of a pound and three-quarters of a wooden log.

Can you calculate the weight of the entire wooden log?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

What month of the year has 28 days?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.