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Concepts:
Flammable solids, surface area, minimum explosive concentrations (MEC)
Safety:
Safety glasses MUST be worn at all times by demonstrator and the audience.
Safe distance from students.
Away from fire sprinklers or smoke alarms.
Best for non-combustible surfaces (Floor).
Fire extinguisher.
Be careful not to use too much as it can fall out causing flames to hit the ground. Smaller is better.
Equipment:
Plastic tubing with BBQ lighter zipped tied at one end.
Preparation:
Pour some lycopodium powder into the tubing, about 1 oz or so.
Ensure the BBQ lighter is functional.
Demonstration Instructions
Pour a small amount of the Lycopodium on a table and try to ignite with the lighter.
Nothing happens as there is not sufficient surface area for the individual pieces to light and propagate.
Now for the second part below...
Find an area with about 10 feet of stand off distance from students.
Grab the BBQ lighter with your left hand, also holding the tubing.
Extend your arm fully, light the BBQ lighter.
With the other hand grab the end of the tube, put the tube in your hand so tube only extends up to your middle finger.
Take a deep breath, and blow into your hand/tube. Your mouth should not touch the tube only your index finger.
Blow very hard!
Observations:
Fire Ball! As you blow out you are forcing the small organic pieces to separate and disperse like in a sugar/flour mill. In these types of mills there are always particles in the air. If the concentration is sufficient and there is and ignition source you will have an explosion!
Learning Outcomes:
Combustible dusts are dangerous!
This is going to be important in 3D printing. Many exotic metals are used in this industry and house keeping is paramount!
Most hazmat teams do not have dust meters to figure out the particulate counts.
Chemical Disposal:
None. Used up in demo.
Additional Information:
Large scale demo, Myth Busters did this with coffee creamer https://www.youtube.com/watch?v=yRw4ZRqmxOc
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