Thursday, April 4, 2013

Science goes BOOM!

Over the last 24 hours on Twitter there has been some interesting discussion on chemistry teaching methods. Specifically, explosions.

Most of the comments that I saw  were of the opinion that demos should be more positive - which, to me, means that they think a balloon exploding is negative (which I just don't see). Sure, you can overdo it. You don't need an explosion every day and there are certainly plenty of other really interesting demos to help teach. But I just don't see what's wrong with a little bang every now and then. For example, filling a balloon with hydrogen and oxygen will produce a loud bang. A balloon with just hydrogen will not be as loud. Why? Both balloons are explosive by the reaction:

2{H_2} + {O_2} \to 2{H_2}O

However, the balloon that is filled with hydrogen and oxygen reacts much faster, and thus the louder explosion (it reacts faster because hydrogen and oxygen are already mixed). There are plenty other examples (butane balloons compared to propane balloons, for one), but the idea is the same - sometimes an explosion can help you teach.

I can see both sides to this story. My undergrad education was very slim on explosions. In fact, I can't remember a single explosion during a lecture. I don't feel like I missed out. Chemistry was interesting to me for more reasons than the explosions. On the other hand, in graduate school I've seen more than my fair share of explosions (seriously, every professor here is like some deranged pyromaniac). I've seen students become interested because of the demos (though I don't think I can say with any certainty it was because of the explosions).

Of course I can see the point that Dr. Smith is making. If we're just blowing something up, or using an explosion to supplement poor teaching ability we're obviously doing something wrong. An explosion shouldn't be a crutch to keep students interested - Chemistry can be awesome without the explosions. A demonstration should have a specific purpose and should be tied to a specific concept you're trying to teach. Sure, there are times when luminol, a howling gummy bear, or elephant toothpaste are the demos you should be using, but every now and then you just need a good explosion.