HE Student Knowledge Base URL: http://cmg.screenstepslive.com/s/MacmillanMedia_StudentHelp/m/52448/l/609357
Yes, but when you exit a lab, it will reset the next time you enter it. Any lab work you've done will not be saved for the next time you enter; only your lab notes will be saved if you have used the Save button to save them.
While you wouldn't want to exit in middle of an experiment, you can complete different experiments in your lab at different times. But if you've completed an experiment and want to start the following experiment at another time, be sure the future experiment doesn't involve materials you've created in the previous experiment.