ONLY FOR THE EXPERIENCED INSTRUCTORS! DO NOT TRY THIS AT HOME!

If you have not done this before you must tdo this with an experienced instructor to learn how to do the demo properly. There are inherent risks when using open flames as demos! But if you follow strict safety protocols, practice it can be done safely!

Often this experiment is called the Methane Mamba or Fire Bubbles. This demo is a class favorite. Remember to do this demo in the right location away from fire sprinklers or you are gonna get an unwanted shower! It makes GREAT pictures but need a dark background. Bigger is not always better! Lots of water! And if your participates are big hairy fellas, they may loose a bit of hair on their arms if they have not prepared correctly!

DEMO #1

Concepts:

Lighter than air flammable gas, compressed gas cylinders, pressures, CGA numbers, 4-gas correction factors

Safety:

Safety glasses MUST be worn at all times by demonstrator and the audience

Adhere to the safety protocols

Ensure you have adequate overhead space, not under fire sprinklers!

Fire extinguisher

Emergency shower, decon, water

Bubble placement, only on the hands, NOT under hands, NOT on wrists or arms.

Adequate water on hands/arm

Pin long hair back.

Remove bracelets, watches.

Equipment:

• Methane, compressed gas cylinder (Air Gas Linde or local gas supply)

• CGA #350 dual stage regulator barb fitting (Air Gas Linde or local gas supply)

• Flexible tubing that can connect to the barb fitting (Small funnel that fits in the tubing is optional to make small bubbles that can rise in air)

• 5 gal. bucket for water. Heat conducting properties of water will protect your skin!

• Dawn soap & glycerin (Purchase at pharmacy)

• Container with wide opening around 6-8"

• BBQ lighter

• Table

• Fire extinguisher

Preparation:

• Fill the 5 gal. bucket 1/2 to 3/4 with water

• Add a generous amount of soap and glycerin to the wide mouth container add water and mix. Try not to make too many bubbles. Let it sit for a bit so the bubbles rest.

• Remove the cylinder hood and attach the dual stage CGA #350 regulator. Ensure the cylinder is secured and located away from the flames.

• Attached the tubing to the regulator barb fitting.

Demonstration Instructions

• You need 3 participants to make this happen. Safety glasses for all!

  • Gas handler = experienced instructor

  • Lighter = informed student on how to light the bubbles (NO PROPANE GAS TORCHES)

  • Bubble holder = participant

• Best done in the bay at the fire station, do not do this inside with low ceilings. Need high ceilings.

• Ensure the bubble holder (Participant) fully submerges their arm in the clean water up to elbow area just before the demonstration. Remove watches or other large jewelry, small rings are ok.

• The gas handler will turn on the Methane cylinder, and adjust the gas flow appropriately, you do not need a lot.

• Bubble the gas into the soapy water solution to create bubbles. Don't make too many as they may float up and away. Create a small mound of bubbles in the dish. Remove the tubing and close the gas flow.

• Have the bubble holder flatten their hand, keep fingers together and form a small cup in hand. Gently start by slicing into the water vertically first until you get just above the water level then turn hand to horizontally and slowly scoop the bubbles up in the dish.

• Bubble holder will FULLY extend their arm, keep fingers together and flatten their hand.

• Gas handler will then remove all bubbles on the underside of the hand by wiping them off. Take all bubbles off the wrist/arm area. Bubbles shall only be on the hands! A 6-10" mound is good.

• Once the gas handler has checked that safety glasses are on, bubbles are in correct position and hand fully extended away from bubble solution then the lighter can proceed.

• Gently touch the top of the bubble mass and the methane will ignite, the gas flames can go up ~10-15 feet sometimes.

• The bubble handler is not to move their arm, the flame will dissipate in seconds and the water will absorb the heat

• This can be repeated as needed. Be careful and make sure the cylinder, bubble and lighting area are all segregated by at least 4-6'

Observations:

As soon as the bubbles are lit you will see a mushroom cloud of flames take off straight up! Saucer sized eyes and a whoa from the bubble holder. Surprising how well water absorbs the heat of the flames, your hand does not even get hot! The colors of the flames is that classic orange organic flame with clean burning fuel like Methane.

Learning Outcomes:

• Lighter than air flammable gas. You can talk flammable ranges, vapor pressure, monitoring strategies, laster Methane detectors

• Before you start the demo cover the compressed gas components.

  • High pressure vs low pressure

  • Compressed Gas Assocation (CGA) numbers found on valve neck and regulators

  • Relief components such as fuesable plugs vs pressure relief valves (Propane) or frangable discs

• Propane vs Methane density (RGasD)

• 
  

Chemical Disposal:

None

Additional Information:

• This demo creates great pictures! Best done in the early morning hours at the start of class. Less ambient light and use a dark backgroud.