-->
Home Store Project Ideas Project Guide Ask An Expert Blog Careers Teachers Parents Students

Scientist's Pick: Minty-Fresh Chemistry

Last month, Staff Scientist Dave opened a Science Buddies meeting with a small can of breath spray, a gas grill igniter, a film-canister, a homemade wooden apparatus to "hold" the canister in place, and the question: "Is it okay if I set this off in here?"

A few minty sprays into the canister, a few clicks of the lighter, and the canister was propelled across the room with a noisy "bang."

In subsequent demonstrations, Dave showed other ways to expand upon the initial experiment, even taking advantage of tire gauges and balloons, all the while pointing out the chemistry (and equations) behind the experiment.


Project: Getting a Bang Out of Breath Spray: Studying the Chemistry and Physics of a Small Explosion
Scientist: David Whyte
Science Buddies' Difficulty Level: 8

I chose the topic for Getting a Bang Out of Breath Spray because it involves making a great toy, a "Binaca bomb" that can be used to explore the chemistry and physics of a small explosion. To make the device, a small amount of ethanol (from Binaca breath spray) is spritzed into a film canister. The top is quickly placed on the canister, and the ethanol is ignited with a spark.


If all goes well, there is a loud "pop," and the canister flies through the air!

I like this project's vivid demonstration of how energy can convert into various forms: chemical energy from the combustion of the ethanol is converted into thermal energy (the heat that makes the gases expand in the canister), which in turn is transferred to kinetic energy in the form of the flying canister.

I also like that the project offers plenty of opportunity to explore questions about what is actually taking place during the explosion. There is more than just a "bang" and a "projectile" happening here. Some of the questions that can be asked include:

  • What is the pressure in the canister at the moment before it separates from the top?
  • What is the volume change that occurs when the gas is ignited?
  • What is the kinetic energy of the canister?

The project contains the science to determine the answers to all of these!

The project also has a nice mix of measurement and calculation. For example, the approximate temperature of the hot gas is calculated based on measurements of the pressure and volume.

Oh, and did I mention the project involves explosions?

~ Dave


Science Buddies Science Activities

Science Buddies and Autodesk for Student STEM Exploration


thumbnail
TIME recognizes "Ebola Fighters" as Person of the Year. Students explore science related to Ebola epidemic.

thumbnail
A science project, especially an advanced one, may have a longer shelf life than just a single fair or a linear competition circuit. Top science students may find many events and venues in which to enter and showcase their research and findings.

thumbnail
A new classroom activity, sponsored by Cubist Pharmaceuticals, helps students see how populations of bacteria respond to antibiotics. Using a colorful dice game, students roll the dice to see how many bacteria respond to treatment each day.

thumbnail
School and family science weekly spotlight: explore variables related to individual vocal range.

thumbnail
Support Science Buddies to help us keep our science education resources free for millions.

thumbnail
How do your favorite veggies compare when it comes to generating power? Find out with a hands-on science electronics kit from the Science Buddies Store!



Your Science!
What will you explore for your science project this year? What is your favorite classroom science activity? Email us a short (one to three sentences) summary of your science project or teaching tip. You might end up featured in an upcoming Science Buddies newsletter!



You may print and distribute up to 200 copies of this document annually, at no charge, for personal and classroom educational use. When printing this document, you may NOT modify it in any way. For any other use, please contact Science Buddies.