We did a round the lab trip for density stations this week, the seventh week of school (thus the 6th lab). We saw moth balls in vinegar get raised with air bubbles, saw that hot water is less dense than cold water (with a density ball--a ball with a density very close to 1 g/cc), ranked cylinders from least dense to most dense, and tested antifreeze concentrations. I had students wear safety goggles and aprons, which they don't like that much, but which is much, much safer and better practice for a scientist.
Sweet j.
