Why it is important to make clear the purpose of experiments in teaching.
As you all know by now, I am a big fan of hands-on experiments in teaching. One reason is that I enjoy running the experiments. Another is that students generally enjoy running experiments. And the third is that I believe that hands-on experiments offer learning opportunities that cannot be replaced by any other form of teaching, and that are a valuable and necessary part of any science and engineering education.
All the more reason to pay close attention when colleagues say that they don’t see the value in letting students do experiments themselves. In the paper “What is the purpose of this experiment? Or can students learn something from doing experiments?” Hart et al. (2000) state that despite of many historical claims of the value of lab work in schools, research often doesn’t support the expectation that lab work leads to meaningful learning. They give many reasons that can prevent students from actually learning in lab work settings, for example that students are, in those settings, mainly concerned with the completion of the task at hand, which can overwhelm any serious learning possibilities. In the same vein, lab experiments can lead to a cognitive overload because there are so many things to recall at the same time. Most importantly, the authors state that students often fail to relate the hands-on experiments to the other aspects of their learning.
The authors go then on and run a lab course which is not primarily aimed at conveying scientific knowledge, but which has as a main purpose that the students understand how the scientific process works. From that successful course, the authors come to the more optimistic conclusion that lab work can actually help learning – if not learning of science knowledge, so at least of other things.
The main point I am taking from the article is that the purpose of the lab work (the pedagogical reason why the teacher chose to run an experiment at that specific time) and the aim of the experiment (for example proving Newton’s law) are two very different things, that need to be communicated as two very different things. Students need to be aware that the process is the most important thing right now, or their learning to use a specific instrument, or whatever the purpose is, so they can focus and consciously engage in the learning process rather than focus on something meaningless (like finding the correct numbers to write in the lab report without understanding the process).
This article is very interesting to me, because I am currently trying to structure an article on the purpose of lab work at university. Apart from stressing again the importance of discussion in the process, I think we need to clearly distinguish two purposes of lab works: understanding of concepts and learning of methodology. And these two types need very different labs.
If the purpose of lab work is conceptual understanding, experiments need to be simple, easy to conduct and quick. That way students have the time for discussion and reflection that they need to actually learn and understand.
If the purpose, on the other hand, is to learn a methodology or how to handle an instrument, the experiments can be a lot more complex and time-consuming. But it is important that in this case it is clearly communicated that the purpose is to learn a new practical skill, otherwise students are likely to just go through the steps, completing them one after the other without actually engaging in the learning process.
And then in both cases it is of course important that the whole course is designed following the concept of constructive alignment: If the purpose of the experiment is to learn how to use the scientific method, this is what should be practiced during the course and also what should be evaluated in the end, regardless of whether the scientific method led to the correct results of any given experiment. If, however, the purpose is to learn to use an oscilloscope, this is what needs to be practiced and evaluated – not whether the students know any theory about oscilloscopes.
So what is the purpose of the experiments you are having your students run?