I have always argued that educators have to be careful with the concept of “learning by doing.” The fact that a task requires motor activity (hands on) does not require that it also involve mental activity. This is not my original idea – Ausubel (an underappreciated scholar in my opinion) described certain tasks as rote discovery implying exactly the same thing. My favorite classroom example making this point is to compare the instructions for baking a cake (from a box) and the instructions for performing a high school chemistry experiment.
It appears the National Research Council has reached the same conclusion:
The typical high school lab is an isolated add-on that lacks clear goals, does not engage students in discussion and fails to illustrate how scientific methods lead to knowledge, says a report by the National Research Council.
(AP News Report) The full report will be available later this fall.