John C states, "Conservation
reasoning should have clicked in by then, but it usually does not. Even in
the senior year of HS there are students who have still not grasped
conservation reasoning."
I ran into this very issue 3 weeks ago. I am using McDermott's Physics By Inquiry with some juniors and seniors. They were working on water displacement. A group of 3 students had difficulty deciding if a graduated cylinder must be emptied in between each trial. They had a 50 mL cylinder with some water. Measure the initial volume, placed an object in the cylinder, measured the 2nd volume. Then they could not decide if they could simply add another object for the next test, or if they had to completely empty the cylinder and start over. It took a full 4 minutes of discussion for them to reach the conclusion that they probably /could/ just add the water. One student stated that while they probably could, it would just be easier to dump the water and start over...
Normal kids. Typically categorized as smart and hard working.
Eye-opening.
Paul Lulai
Physics Teacher
Medtronic - St Anthony RoboHuskie 2574
3303 33rd Ave NE
St. Anthony Village Senior High
Saint Anthony Village, MN 55418