Day 30

Today we continued the station rotation activity, and discussed conversions involving squared and cubed units (see EDpuzzle for related video).

The PhET Density Simulation activities were also returned and some key points were shared.

• Volume of the objects can only be measured if the object is completely submergedin the water.  If you kept getting density values of 1.00kg/L for multiple objects (especially the ones that floated), you probably did not have the object submerged.
  
• Substances with densities >1.00kg/L will sink in water...all the way to the bottom.  There is no way to tell just by observation which object is the densest without knowing the mass of the object compared to others that also sank.  Objects that float, however, can be ranked by density, based on the proportion of the object that is submerged.  The higher the proportion of the object that is submerged, the closer that object's density is to 1 kg/L; the smaller the proportion of the object that is submerged, the smaller that object's density is (less than 1kg/L).
  

A sheet of practice density problems (requires some thoughtful analysis and application of the concepts of floating/sinking and material density) was also distributed.  You can access the handout here (will require your Office365 login info).  These would make for some nifty open-ended test questions...

Element Quiz #4 (Metalloids & Nonmetals) is tomorrow, as well as time to ask questions in preparation for Friday's Unit Exam.