What is the main purpose of the lab experiment?

M: Have you done the lab for physiology yet -- the one on taste?
W: Yeah, it was kind of fun -- mapping the taste buds. Didn’t you think so?
M: I’m doing it this afternoon. How long will it take?
W: It went pretty quickly -- under an hour, anyway. See first you mix up the four solutions.
M: You take water and add either sugar, lemon juice, salt, or -- oh -- What was it?
W: Bitter quinine.
M: That’s it -- oh -- then what?
W: Then all you have to do is taste each sample and describe where each flavor seems most intense.
M: Is that hard?
W: Not really. One thing to remember though -- not all the taste buds are on the tongue.
M: Right. I’ll keep that in mind. And thanks for going over this with me. Maybe we could talk about this after I’ ve tried it -- we could get a pizza or something.
W: Great. Give me a call.