What Do You Want Me to Do In Lab?

Many introductory physics labs involve a low friction cart on a track. Many introductory physics labs involve a low friction cart on a track. Rhett Allain

Here are some typical questions I get from students in the introductory physics lab:

Do you want me to make a graph?

How many different masses should I measure?

What angle do you want this ramp at?

What units do you want me to use?

Here is the answer. I really just want one thing. I want the students to build a model. What is a model? It could be anything. It could be an expression for the force a spring exerts as it is stretched. It could be an equation that shows the relationship between friction force and other things. A model could be a numerical calculation that shows how an object falls with air resistance.

That’s really all I want from lab students. I want them to explore and build. Oh, I know it’s tough building models. You have to start with simple things like a free falling ball or a cart rolling down a ramp. On top of that, that are other problems. You need to understand how to make a graph and what it means. You need to know how to use different equipment to collect data. You need some data analysis skills. Maybe you need to know how to create a numerical model.

Because it’s not so easy to build models, I try to help. I sometimes will give students a model for them to collect data and compare (like with friction). I will sometimes show students the steps that I would use to build a model so that they can follow.

But in the end, I really don’t want the students to do anything in particular. I want students to be builders, builders of models. Imagine this was an art class and a student asked “what color do you want me to paint this flower?” My answer would be “well, what are you trying to accomplish?” In the end, lab is like art class. The students need to create something and I am there to help.

Students in lab are not my assistants collecting data. I am not training them to follow instructions, I am training them to be humans. If lab was all about following instructions, we could just use robots. Robots are good at stuff like that.

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