Learning is Like Mountain Climbing

Suppose I was a mountain climbing coach. For the day's lesson, the mountain climbing class would aim to get to the top of a mountain. Along the way, the terrain varied in climbing difficulty. Some parts were just foot paths, but some parts were quite steep requiring some more technical skills.

So here we are, everyone is happily progressing towards the summit. That is until some climbers are having trouble.

Climber: "Hey climbing coach! I can't get past this super steep part!"

My reply would be:

Me: "Well, let's see what you are doing wrong. Ah, look, you are trying to use your arms too much. Your legs are very strong, use them."

Yes, this part of the climb is difficult. Some of the climbers are past this part but some are still working on it. Then they call out again.

Climber: "Climbing coach! We are never going to make it to the summit by the end of class. Will you just lift us over this hard part?"

Me: "If you don't make it to the top today, that is ok. You really need to work on your skills on steeper parts of the mountain or you will never become a better climber."

If the goal of this mountain climbing class was to get to the top, couldn't we just take the ski-lift or something?

What about a physics coach?

"Physics Coach" is my new preferred job title. One of the classes I enjoy coaching is the physics for elementary education majors using the curriculum Physics and Everyday Thinking. However, there is one part of the mountain in this book that I always dread. Let me set up the situation for you.

In the third chapter, students look at interactions between things that don't touch - gravity, electrostatic, and magnetic. They have already looked at force and motion as well as energy and interactions. For this activity, they are looking at the gravitational interaction.

Most activities let the students collect experimental data that they can then use to build ideas. For this activity, there is a narrative and a demo of the Cavendish experiment. Essentially, this is device that shows a gravitational interaction between masses (where neither of them are the Earth).

Here is a picture of the Cavendish demo:

The small masses inside the glass (to block air currents and stuff) are on a rod suspended by a wire. This allows the two small balls to rotate horizontally with relatively small forces. The two large masses (notice how I didn't call them big balls?) are placed on the outside. There is a gravitational interaction between the small and large masses that makes a notice movement in the small masses. Boom. Gravity. Interaction between masses where none of them are the Earth.

After this demo (and some other stuff), the students try to come up with responses to several questions. This is a normal part of the curriculum. Students are used discussing the questions with the class and using evidence to support their answers (they are familiar with the procedure even if it doesn't make them too happy).

And here is the steep part of the mountain climb:

Some say that the rotation of the Earth is the cause of gravity. What evidence do you have that supports or refutes this idea?

Just to be clear, the students have collected evidence about forces and circular motion. They don't have a mathematical model for centripetal acceleration, but they do have evidence that a sideways force makes something turn and a continuous sideways force makes an object move in a circle.

Why do I dread this question? I don't think I dread it because students have trouble with the concept, it is a tough idea. (see the Veritasium video on the spinning Earth - not the same, but related). I dread it because when the students get stuck, they don't want to struggle with the idea, they want to skip the idea. They want me to lower a rope and pull them up.

Really, they can survive the course even if they don't figure out this spinning Earth puzzle. There is nothing else that builds on this idea and it isn't on the test. So, I sit back and let them struggle. No rope will be lowered today.

The worst part is that there are still some students standing at the bottom of this steep mountain. They are standing, and not trying to climb. They are telling me that my job is to pull them up with a rope. My response: "remember, use your legs - they are very big muscles."

More Evidence Regarding the Spinning Earth

Still, I am a sucker. The view from the top of this mountain is quite nice and I would like the students to enjoy it. To this end, I made the following video (which I showed to them during the next class):

I told them to observe the pieces of clay stuck on the side of the ball as it spun. If it spins super fast, the clay falls off. Some students seemed to enjoy but others were still angry about the steep part of the mountain. Maybe I should have used this spinning video instead.