Heya shaunthesheep, it depends on what you would like to study. Most science courses are between 3 and 4 years. I did a 4 year course. This meant that I could go to America for a year and try out other labs. Normally if you do a 4 year course you can do a placement like me, or go and try industry out (like drugs companies). Are you thinking about science at university?
Yes, 3 or 4 years (depending on whether you want a bachelors degree or a masters degree. Then another 3 years if you do a PhD. (although it can take longer, depending on how quickly you write your thesis)
Like Mike said you can sometimes do a 4 year version of a 3 year course with the extra year being spent working in a company. The material you learn at university is the same, but you get an extra year of experience.