Save the Gummie Bears, Save the World!gummies

by Amy Cannon

I recently received an e-mail with a link to an article that had the title "Chemistry class explosion injures seven." I was hesitant to open it, worried about what disaster I would find inside, but did anyway. The article was about a local chemistry teacher who was demonstrating a reaction between potassium chlorate and "food" when the reaction went "awry" and exploded upon her and seven students. Luckily there were no life threatening injuries, just minor cuts and burns. But, despite these "minor injuries," my mind still went to that classroom on that day...

I wondered what the teacher was trying to teach the students; I wondered how the students felt upon seeing that accident; and, I wondered how common this type of demo actually is in classrooms today. Further investigation lead me to find that this is a fairly common demo used by chemistry and even non-chemistry teachers which involves the addition of a gummy bear (typically) to warmed potassium chlorate to produce quite a violent combustion reaction. There are many, many YouTube videos of these poor gummy bears being tortured for our viewing pleasure. But why? Why do we insist on torturing these delicious treats? To teach a lesson? To increase student interest in chemistry? Because we have something against gummy bears? All of these questions led me to write this note to you.

Let's first consider the science of this gummy bear destruction reaction. I am a chemist after all, and I always think about the science first. What can we teach students about chemical reactions or chemical reactivity by this demo? We are essentially performing a combustion reaction where potassium chlorate (KClO3) is reacted with sugar or sucrose (C6H12O6) and oxygen to produce carbon dioxide, water, potassium chloride and lots of heat.

Potassium chlorate it turns out is quite reactive and can put on quite a show upon prompting (or in some cases, without prompting… yes, it is quite dangerous). It is used in EXPLOSIVES! Yes, explosives! Do a simple Google search of 'potassium chlorate' and you will find the gummy bear demo, along with another favorite of "instant fire," which involves the mixing of solid potassium chlorate with sugar – upon the addition of a drop of sulfuric acid will cause a violent reaction which typically ends up producing so much heat as to explode the Pyrex glass beaker it is held in. In my experience as an industrial chemist – I find explosions to be very BAD and they typically end in the loss of life or the devastation of neighborhoods. This is not something to show children as a demonstration of a typical chemical reaction. These are examples of chemistry gone bad!

In that Google search of 'potassium chlorate' you will also read all kinds of warnings about the reactivity of the compound, with warnings not to scrape it out of the jar too vigorously because it can produce sparks and therefore combust into flames. It decomposes pretty readily into potassium chloride and oxygen (with lots of heat) – and, we all know that oxygen is a key component for keeping a fire going. If it decomposes this readily, then maybe that jar that has been sitting around since the dawn of time in the chemical stockroom might be slightly more reactive than a fresh batch… something to consider.

Ok, I'm going to get off of my soapbox for a moment and think beyond the science of this demo. From what I have heard another goal of this demo is to "peak student interest in science." Now, let's think for a moment about that classroom that experienced the accident as a result of this demo. My thoughts are that the accident certainly did not peak student interest in science, but rather turned a whole lot of students OFF to chemistry. They now equate it with danger, explosions and hazard. Who would want to put themselves in harms way and pursue a career in such a dangerous field? Now, as I stated previously, I am a chemist. I am actually trained as a green chemist. And, even as a green chemist, there is a certain amount of risk that I must take in order to work in a lab. I work with chemicals of varying levels of hazards, even as a green chemist. But, for me, I accept this risk because I know that each and every day that I am in the lab I am trying to be better than the previous day. I'm working towards a zero emission, zero hazard, zero waste process. With that said, I ask you to consider what level of risk is acceptable. What level is acceptable for a high school classroom? As a trained chemist, I am able to understand the nature of the materials and chemicals I work with. But, for a student who is just learning the in's and out's of the science – how can we put them in situations where the risk is so high?

Regardless of whether we continue to use these type of demos in our classrooms, I ask you to consider the following questions before beginning:

  1. What is the content of the lesson? What is it that I want to teach the students?
  2. What am I teaching my students about the field of chemistry or the profession of a chemist?
  3. What take away lessons do I want them to have?
  4. What level of risk is associated with this demo or laboratory exercise?

Thinking about these four simple questions might lead us to re-consider the demos we use or the lessons we adopt. Just remember that there are many, many ways to demonstrate a chemical concept – many can be found on our website (free-of-charge!). We can do so much without explosions and fires. Everyday in classrooms students fall in love with art, literature, mathematics, history and foreign language - and, nothing ever gets blown up, explodes or lights on fire in those classrooms. And, if you still want to demonstrate a concept and can't find a good substitute for that explosive reaction or the other dangerous demo that gets the "oooh's& and "aaah's" out of the students on a regular basis, then please, please send me a note. We are always looking to expand our portfolio of offerings and we are always looking for another way to amaze students through green chemistry hands-on experiences.

We find that students are quite excited about green chemistry because it offers a platform for them to use their creativity and apply it to solving problems. Students learn that chemists are innovative problem solvers and they hold an essential piece to the sustainability puzzle. And, we guarantee that this message is one that resonates deeply with today's youth. Through our outreach and curriculum programs we have found that many students are turned on to science that would otherwise not have been. And, this is exactly our goal – to inspire the next generation of scientists that will help us create sustainable, green chemistry solutions to global problems. We believe this to be quite exciting. And, yes, we have gotten many "oooh's" and "aaah's" from students as they learn about chemistry through this lense. Oh, and, we also get to teach them a thing or two about chemistry without having to worry about the risk of being the next headline titled "Chemistry class explosion injures seven."