What ARE my students actually learning during this long term project (PBL)?


In an earlier post, I discuss some of my unit planning that (I hope!) further breaks down a few of these misconceptions - my students are not teaching themselves on google. They are weaving back and forth between learning content and the larger reason for learning the content.

However, every single one of these comments above are valid. It is really difficult work to ultimately balance individual accountability and group accountability. Every student needs to master basic stoichiometry before they leave my general chemistry course.

Grateful Grading of Labs?

Thank you for your feedback, students!

One challenge I have is knowing how to evaluate labs properly. In writing my new lab manual, I am setting up rubrics for each lab. The ultimate goal is for this manual to be used by all instructors across the chemistry department at our community college, so they need to have a consistent grading system. Writing these rubrics has been challenging. 

Solubility and Models

First, I had my students examine the conductivity of a puddle of water the size of a nickel. They checked for conductivity. Then they took a very small amount of sodium carbonate and a fresh puddle of water and pushed in a few crystals from the side.  You can still see the crystals in the water but it tested positive for conductivity. They had to explain this. They did the same with a fresh puddle of water and a few crystals of copper (II) sulfate. Again, it tested positive for conductivity but they could still see the blue crystal. Finally, they started again with another fresh puddle of water, pushed a few crystals of sodium carbonate on one side and on the opposite side they pushed in a few crystals of copper (II) sulfate.  After waiting five minutes, a solid dull blue precipitate formed in the middle.  Also, the drop tested positive for conductivity.