Continuity mistake: When Meg finally Realizes her feelings for Tim she puts her legs on his lap. The angle changes and she does it again.
Continuity mistake: The scene where he gives his lecture before being called out you can see 3 small measuring instruments on the wall on the right below the board. Once Ed begins to mumble during his lecture there are only 2 instruments on the wall, and they've been moved.
Continuity mistake: When Meg, Tim, and Walter are on the sailboat, from one angle (facing forward) the water is smooth whereas from the other angle (facing aft) the water is choppy.