In previous posts, I have been writing about teaching problem solving (here, here and here). This post describes a strategy that appears counter-intuitive, until you think about what you really want your students to learn.
When you use this question in class, which of the following learning goals is most important to you:
A: learning how to solve this type of problem
B: finding out how much vertical supporting force the rock really supplies.
I’m assuming that you don’t really care about the answer to the question.
When you set this question, any student who can’t solve it is actually less likely to solve it or a similar one next time (Hattie and Yates. 2011 – Visible Learning and the Science of How We Learn. p151). Your student is so caught up in the goal (solving the problem) that she has no working memory left to reflect on learning the strategy.
This blog describes the strategy that prompted John Sweller to develop Cognitive Load Theory (CLT) – the Goal-Free strategy (read more about its history here).
Reducing the cognitive load allows the learner to learn. In the question above, simply cut off the bottom line. You then have a situation to explore with your students – the boy on the plank.
I like to go cooperative at this stage, asking students to discuss the situation in turns. I use a strategy I learned from Jakob Werdelin, a cooperative learning specialist, called Word-Round. In groups of four, students have 20 seconds to talk about the situation in the question. After 20s, the next team member speaks. The teacher listens in to pick up any useful and interesting points to share with the class after the Word-Round is finished. (Another cooperative strategy that works well in this situation is Think-Pair-Share).
A considerable amount of learning has happened by this stage, especially if your learners recognise the situation as a familiar one involving beams with two supports. It is possible that your students are now ready to tackle the problem. You may wish to demonstrate the working yourself or you might prefer to give a partial solution and allow your students to complete it.
Going Goal-Free might sound directionless, but it is the fast route to problem solving.