<p>Science labs vary. Bio and chem labs are usually 4-5 hours and physics is about 3-4. Granted some people finish early and can leave early, and others take longer and stay later.</p>
<p>There is an instructor during lab, so you definitely are supervised! In my experience, all labs start off with the lab instructor giving an explanation of the days activities. They’ll introduce key formulas you’ll need for computations, certain computer programs if those are needed, cover all the “stations” in lab if there are different activities going on. After that, you go about the day’s activities: sometimes you focus on one specific thing (eg. dissection, titration, etc) and other times you’ll focus on a variety of different things.</p>
<p>Bio and chem labs have a lot of step by step activities that have to be completed. Keeping a good lab notebook is essential in these labs, since you will use those notes to write up your lab reports afterwards. Physics labs had a general overall theme, and once you finish the calculations, you are free to leave. Physics instructors place much less importance on your lab notebook and lab reports in general, imo. They tend to just want the right thought process and answers, where I feel chem/bio want everything (procedure explicitly noted, materials list, etc).</p>