Charlie wants to know when he is going to learn science - yesterday we decided that he is a hip hop scientist (and inventor).  
Here is what I found to help him out:
Neuroscience for Kids -- link enclosed -- so I can find it again.
http://faculty.washington.edu/chudler/chsense.html
Maybe he can solve the mystery of migraines!  Though I don't want to wait that long...
Just a snip from the site:
The Senses - Hearing, Smell, Taste, Touch, Vision, Working Together 
Our SENSES tell us:
What is out in the environment. 
How much is out there. 
Is there more or less of it than before. 
Where is it. 
Is it changing in time or place.