Tuesday, February 26, 2008

Revamping Intro Physics Laboratory - Part 2

So what is the main purpose of intro physics laboratory?

Keep in mind that MOST students in such courses are NOT physics majors. In fact, for many, these are the only physics courses they'll ever take. So I see it as the best opportunity to introduce to the students how physics actually work. How exactly do we consider something to be valid in physics? After all, anyone and everyone can come up with some "theory" to describe something (and in the age of the internet, everyone does!). How do we select which ones are valid and which ones aren't? It all comes down to experimental verification. How we know something to be valid come from our empirical observations. Therefore, proper experimental techniques must be crucial since it can determine what is valid and what isn't. This is where the acquired skills come in.

When I say "skills", I don't just mean physical skills, such as the efficient way of using an oscilloscope, or one's agility in soldering a piece of wire. It also includes mental skill, which is the ability to think through a problem, or a nagging feeling that something isn't quite right. It also includes the ability to know what is the best and most accurate way of doing something. For example, why can't a student simply make one measurement of the restoring force of a spring, make the corresponding measurement of the spring extension, and then plug those values into the Hooke's law equation to find the spring constant? Why do we have to make a series of measurements instead? The ability to know why we need to do that is an acquired skill in proper technique to test a particular relationship of two different variables. One acquire such skill after consciously and repeatedly learning ways to make such tests. However, the students need to be told that these are the skills they are being taught, so that they are consciously aware of what they are doing and why. So often, in the usual physics labs, this awareness is lacking and not being emphasized.

What the labs can do is reveal in a very direct way how we gain and verify knowledge. What exactly is the relationship between variable x and y, and how do I test it? How do I know my result is valid? In the end, without one having to tell them point blank, they learn the difference between "scientific evidence" versus other forms of evidence, and they get a glimpse of some form of what people like to call "the scientific method". Considering that most of them will go on to do other things in life beyond just doing physics (or even science), I would think that this ability to have them understand what is involved in determining what is valid is something extremely valuable. This lack of understanding can easily be the cause of why people accept pseudoscience and other flaky ideas. That is why I consider these physics labs as extremely important not just in physics, but as part of a general education of the population.

Since I've already mentioned what is wrong with the current way of doing intro physics labs, I should put my money where my mouth is. What exactly should we do in such courses? In the next part, I will give an explicit suggestion on how to revamp these lab sessions.


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