Avoid These Three Dangerous Chemistry Demonstrations

Chemistry class provides great opportunities for students to learn about the world around them. Experiments and teacher-led demonstrations are an important part of any chemistry curriculum, but unnecessarily risky experiments can go awry quickly and cause injuries to students and staff.

It’s important for all teachers to have an understanding of the risks associated with the chemical demonstrations they perform in the classroom. The student’s safety should always be at the forefront of teachers’ minds and should never be overridden by the need to provide a “wow” factor. Here are three experiments that should not be performed in K-12 classrooms.

Hot Lava Demonstration

In this demonstration using liquid methane, the teacher sets the floor on fire by spilling a flaming test tube on the floor, allowing the fire to spread across the room. It is extremely fortunate that no students were injured during this experiment. An injury could have easily resulted if a student put their feet or backpack on the floor. Any demonstration like this that puts students at considerable risk should not be performed in the classroom. Think of ways to safely engage your class without setting the floor on fire.

The Exploding Pumpkin Demonstration

With Halloween around the corner it may be tempting to find a way to incorporate some of the holiday spirit into your lesson plan. But experiments like the exploding pumpkin demonstration, which uses chemicals to demonstrate an exothermic reaction, can lead to serious injury. In fact, an Illinois school was sued for injuries a student suffered when the pumpkin explosion was more intense than expected. This demonstration, while thrilling, should not be performed in K-12 classrooms. If you want to perform a Halloween themed experiment, the foaming pumpkin demonstration is visually exciting but less risky. Just be sure to follow all the listed safety precautions.

The Rainbow Demonstration

The rainbow demonstration is another example of an experiment that can pose significant dangers to your students. This demonstration features flammable solvents to show how different elements produce different colors of light when burned. The rainbow demonstration has resulted in a number of student injuries, yet some schools continue to allow it in the classroom. The American Chemical Society Committee on Chemical Safety has repeatedly recommended that rainbow demonstrations should be discontinued, stating that highly flammable solvents should not be used in demonstrations or should be carried out only in a properly functioning chemical hood. There are a number of alternative demonstrations that illustrate the same educational concepts but do not involve the same hazards.

Weighing Educational Value Against Risk

The reason these demonstrations are popular is obvious: they are exciting! Regardless of how impressive these experiments are, they put your students in unnecessary hazardous situations. Additionally, students may try to copy the experiment at home creating another layer of potential danger.

It’s not necessary for you to reduce your science curriculum to baking soda and vinegar reactions. However, it is important for you to constantly be weighing the educational value of an experiment or demonstration against the risk it poses. When deciding if a demonstration is appropriate for the classroom, ask yourself: is there a way to illustrate the same concept without putting myself and students in danger? Chances are the answer to this question will be yes. For more information on chemical safety check out the resources in the chemical safety topic or visit the National Science Teachers Association website.