Young Explorers Chemistry and Physics: Lesson One

So, we are officially in class!  My husband, Rob, is taking charge of the class, which runs concurrently with Chemistry. Today the kids are doing Flinn Scientific's Measurement Challenge.  Rob is catching up Anna and doing the volume, mass, and density calculations with Gen, who will help as class aide for the younger boys.  Does this sound familiar?  Co-op operates in a similar manner to your home-school classroom.  Rob want to emphasize data tables, careful notes, units, and a little math.  We're measuring and comparing densities to a bunch of materials: glass marbles, acrylic blocks, metal cubes, etc.