Chemistry explosions are all bang and no buck


I am a chemist and I am heavily involved in science outreach especially in chemistry. I have built a library of demonstrations that I can pull out to demonstrate scientific principles. I also have an array of demonstrations that result in an explosion, not something to brag about when needing to board a flight. The explosions and flames are my least called upon demonstrations. I loathe these demonstrations and use them sparingly. Chemistry is so much more than pyrotechnics and it is an incredible tragedy that this is what it has become to not just people outside of science but also within science. As a chemist of 10 years, I have not once used an explosion in any of my work.

Well meaning science communicators and chemists have used them to grab the attention and awe from audiences in chemistry talks and demonstrations for who knows how long. I have seen too many to count in many guises and for a range of audiences, and all with the intention of telling people about the chemistry of matter. The bits that make up stuff around us and the chemical  reactions of the bits. This mode of chemistry outreach is a dismal failure at representing chemistry and inspiring future scientists. I say this because the vast majority of people whose only exposure to chemistry is demonstrations sum up chemistry with one word, “explosions”. Even students who have yet to step into a chemistry class will say this and then lament about the lack of explosions.

Chemistry isn’t a study of pyrotechnics. I may know the chemical components of what is needed in a firework and the chemical compounds in a number of explosives but I don’t know the first thing about firing them safely. I’m not a pyrotechnician. There needs to be an overhaul of chemistry demonstrations that are trotted out on stage before a switched on public. Let’s face it, people who turn up at these are already interested so they’re not a hostile audience. It’s time they got more than a scaled down fireworks display.

Instead of trying to design a show that encompasses the whole of chemistry, I think shows should focus on aspects of chemistry. This would mean a greater variety of demonstrations, (we’ve got the equipment so let’s flaunt it), and a better representation of what chemistry is and more importantly how pervasive it is throughout science and everyday life. Let’s see more chemistry shows with themes and targeted messages beyond, “Chemistry is awesome and exciting!”.

There are demonstrations involving dry ice beyond placing it in a bottle or an old 35mm film cannister and waiting for a big bang. Yes gases expand and this is an excellent demonstration but given that CO2 is now a much talked about gas, there is opportunity to show people some of its other properties. You could collect CO2 and pour it over a flame to demonstrate the fluidity of gases. It also shows that it doesn’t support combustion and the principle behind COfire extinguishers. Get an empty aquarium, throw in pellets of CO2 and blow bubbles into it and voila, floating bubbles.

Then of course there is the visual demonstration of bubbling CO2 through a solution to change the pH of a solution. The acidification of oceans has entered mainstream media reporting so why not get a sample of ocean water and experiment before a live audience? And with the advent of cheap webcams and livestreaming, leave a shell in acidified ocean water for the audience to monitor over time after the show to see what happens. Chemistry isn’t confined to laboratories and shows so why not encourage ongoing discussion?

Why not bring in some analytical instruments to analyse samples? There are so many handheld devices now and if you have access to them, show them off in action. I attended an open day at a chemical analytical lab and the most popular and busy stalls had working handheld devices. Bring it in and analyse something live in front of an audience in a themed show. Ask the audience for an everyday object they have on them and tie it into the show.

One of the most awe inspiring demonstrations I have seen did not have one explosion. It was a colour show showing off chemiluminescence accompanied with an informative talk. You know that CSI trick where they spray a bottle in a crime scene and then shine a UV light and suddenly the blood splatter can be seen? The chemists behind this talk took that right out of CSI, put it in front of the audience, and showed just how bright luminol can get and with more colour. It no longer remained in the domain of television magic. The speakers did finish off with an explosion but what everyone was talking about after was the much more complicated chemical reactions behind chemiluminescence.

This kind of discussion only comes if the chemistry has content beyond the flashes of light and colour. Content is king. Chemists are not magicians or performers in white lab coats. Every chemist I talk to has a story of intrigue and mystery about their work, and not just the forensic chemists. Each one of us has a mystery to solve and who doesn’t love a good detective story? Why don’t these stories get shared and in doing so shed the snap, crackle and pop impression of chemistry? After all, it’s not the study of a breakfast cereal.

I am not saying do away with explosions entirely but if it means that the rest of the chemistry show talk can’t stand alone without them, then what is the point? Demonstrations should highlight the content and show off the chemistry. No smoke, no mirrors, just the revealing of chemistry in everyday life which in itself is magical. Give people something to walk away with a real story of chemistry instead of memories of a big bang and no buck.

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11 Comments

Filed under Life Observations, Opinionated Orations, Science, Science Communication in Action

11 responses to “Chemistry explosions are all bang and no buck

  1. Elizabeth Christophy

    Thank you! I hate that my students all say “When are we going to blow things up?” There is more to chemistry than that.

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  3. Red Cabbage

    I agree with the main points made in the article. I think that the main focus of any ‘science’ demonstration has to be content. This content should promote interest and participation from the audience – get them thinking, asking questions, and trying to understand what’s going on. I think that there is value in performing demonstrations involving explosives if done properly (I don’t just mean with proper safety precautions).
    Explosions are way cool! I mean this on many different levels. They are typically visually stimulating, but understanding the science behind them is very interesting too, and that’s something which needs to be included when demonstrating them to have lasting value. The audience sees an explosion which gives a red flash…what gives fireworks their distinctive colors? Here’s a teachable moment. You can go as far in depth as you want, but, I agree that explosions have no bang if there is no explanation. I think that this is true though of any demonstration.
    That being said, most of my favourite demonstrations are simple and can be understood by everyone regardless of whether they can derive the equations describing second order perturbation theory from first principles or not.

    • I know explosions are visually stimulating and the chemistry behind them is interesting and you can talk about electron energies, spectroscopy, thermodynamics, kinetics, and even quantum chemistry theories if that floats the boat of the audience. The problem is that the bulk of chemistry demonstrations is just this at the expense of every other area of chemistry.

      As a chemist I am not okay with being represented by one facet of chemistry and that is my problem with chemistry demos with explosions. They seem to be the only type of demonstration around. It isn’t because they are the most memorable but rather that they are the only ones offered up to people.

      There are so many other demonstrations that are way cool.

      The situation has become where every other chemistry demonstration in another area is assumed to be a new area of unexplored chemistry or worse, a novelty. I am an advocate for content in science outreach activities. Nothing wrong with having fun but if an activity didn’t deliver the key message, it failed.

  4. I agree completely. It is tragic how science programs on TV have become nothing but glitz and hand-waving with almost no real content. I recently wrote a post that consisted of little else than quotes from Carl Sagan. I led with the one about how, in an increasingly technological world, people are becoming more and more ignorant about the science behind their daily life. It’s like the always growing gap between the rich and the poor. There is a growing gap between the science literate and illiterate. This cannot possibly serve us well.

    As much fun as sodium and other explosive tricks can be, one of the most impressive chemistry demos I saw involved mixing two liquids which then alternated quite a few times between being black and clear as two competing chemical reactions won or lost. Astonishing!

    Have you noticed that in some of those CSI shows, they don’t bother using UV with the luminol? Just spray, and poof, blood spatters light up on their own. Must be a lot of ambient UV….

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  6. When students say they want to blow something up, I usually give them a balloon.

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  8. I remember my first real chemistry demonstration – I was actually a senior in high school. I saw a professor take a balloon filled with hydrogen and ignite it. The sound. The flash of light. From there, I knew – I KNEW – I wanted to study combustion and explosions.

    I went to school and majored in Chemical Engineering. We didn’t offer a specific major around explosives, but I figured engineering was a safe bet. About my third year of college I started in a lab working to reduce the explosivity of ammonium nitrate on a DHS/DOD contract. It was fantastic. I’ll never forget my first explosion.

    Explosions have their place and are often used to just draw a crowd. And there’s the thought that recruiting young minds to science is a numbers game – get enough people to come out and if you turn 1%, you still sparked curiosity of 5 people. So I guess what I’m trying to say is that the problem is that often – very often, I’d imagine – explosions are used without matching content.

    • That’s my point. The explosions used require a context.

      If recruiting people to science is inspiring the 1% who like explosions, then it’s a job poorly done. There are areas of science that don’t involve any explosions. I do not believe that it’s a numbers game. It is communication.

      I am not okay with the whole of chemistry being represented by explosion demonstrations, let alone the represent all of scientific endeavour.

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