Our Question Book

My kids, especially my seven year old, have a lot they want to know. Sometimes they ask me at a time when I can't get to the answer (like we're in the car) and sometimes I just don't know the answer.
What we decided to do was start a "Question Book". It's a spiral notebook, left out in the open for easy access. When they have a question, they write it down and leave room for the answer. It has helped us out a lot because sometimes they ask questions when we're not near the computer, the library or someone who knows the answer and then we forget.

Some of the unanswered questions we have in there right now are:
Why do bananas grow in bunches?
Where does dust come from?
What makes the weather hot or cold?
How does cantalope grow?

Anybody know?