So why a MacBook?
This is coming from someone who is an Apple fan (although I am posting this using my Surface Pro). Yes the quality of the devices is great, and yes I do enjoy Mac OS X and it's ease of use/seamless backups/speed/lack of annoying things/etc... but really you need to figure out why you are choosing a MacBook.
IMO the MacBook Air is the ideal uni student laptop but it's so old now (heck I bought an 11.6" MacBook Air when I was in uni) that unless you really really like it, it's probably not worth it even though it's quite well priced now <$1k with education discount IIRC. You can install Windows on it too but that almost defeats the point since it'll add quite a bit of cost (assuming you buy the retail version of Windows and not an OEM) and then you're missing out on some of the benefits of Mac OS X. That leaves MBP and MacBook if you're heart is set on a MacBook but in both those cases you'll be facing compromises whether it be lack of ports (and high price) on the MacBook, or just size/weight/price for the MBP.
Before you jump in to this make sure you research what else you need to run - I suspect if you're doing a science degree, you might end up needing Excel and some advanced macros/scripts which won't run on the Mac version of Office as far as I know. It'll also boggle your mind later on when it comes to working on a Windows machine which is what the vast majority of companies use and hence make things harder- I struggle using Excel on my MacBook despite living most of my professional life inside Excel on Windows! It'll also make things easier on you during your degree if you can share stuff easier with friends on Windows/etc.. If after thinking about this you still want a MacBook, then I'd say the MacBook Pro is probably the best bang for buck solution and will cover you in other scenarios - but if it were me, I'd go for the MacBook with it's limitations since it just had a hardware refresh for the new Core M processors, USB-C is becoming more common so charging it should be a little less inconvenient as more people may have chargers with them you could borrow if needed, and it's just a more compact machine. Downside is it's not really that powerful so you won't be playing games or anything on it.
I'd also suggest you consider some of the other form factors or devices whether it be pure tablets (e.g. iPad) or 2-in-1's (e.g. Surface 3, Surface Pro 4). I'd probably avoid a Surface 3 now given it's a year old and hasn't had a spec upgrade (unless you find it for a great deal?) but the Surface Pro 3 and 4 are looking like better value options although you will need to carry the charger with you since it might not be easy for you to find someone else with a charger for this on them.
FYI when I was at uni I used a Dell Mini 9 (a netbook!) which was horrible, and then I moved to the MacBook Air. I also had a work provided Lenovo T_series which was great but damn heavy so I rarely pulled it out. Now I own a Surface Pro 4 (and recently sold my Surface 3) and if I was to go back to uni again, I'd definitely go Surface since it's just so convenient having a 2-in-1 which I can write on, type on, and have enough power to do other things.
