I met this guy in my biology lab class about two weeks ago. He became my new lab partner because his original seat got taken. He introduced himself to me and we have occasionally talked since. He seems like a social, friendly guy. I'm not sure if he's trying to make moves on me or not though. For one I added him on Facebook and he messaged me for my phone number to talk about "biology related stuff" but I changed the topic on the chat because I don't give out numbers to anybody especially him when I just met him. A week later we were talking and walking and he asked for my phone number again. I gave it to him and he texted me that night. We've been texting occasionally but he only texts back if he's not busy or probably when he feels like it. On Saturday he told me that I should drop by my college campus to see a movie (I think with him) but I declined since it was too late at night and I didn't want to go all the way to the campus just to see a movie. He seems to like to poke fun and stuff, but I'm not sure if he wants to be friends or go into the potential relationship zone. I don't know if he treats his friends any differently than me, but I know in my chemistry class he somewhat talked to me during the lecture just to strike conversation. Help?

Oh and he's single and he's straight... at least according to his Facebook. I haven't really seen him around girls (mostly guys).

Since you are the one telling the story, and we've never met him, there is no way we can answer your question. Just continue to be friendly, and if YOU like HIM, there are plenty of little ways to let him know without being too forward. 'That was fun.' 'You have a great sense of humor.' 'Want to work on the bio lab results together?'
Good for you for being a bit cautious about your phone number, and for not going to the movie just because he suggested it. School is a constant juggling of casual relationships vs serious ones. You sound like you have a good instinct.