Hydrogen Oxygen Demos

Concepts:

Fuel and oxidizers mixed create hazardous situations, hydrogen is a lighter than air flammable gas with a wide flammable range and can be explosive!

Safety:

Ear plugs or ear muffs are a must for everyone! The large balloon can set off car alarms.

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

Safe stand off distance if using the large balloon, ~50'.

Fire extinguisher.

Bubble on the Hand demo can be done in a large space.

Large balloon should only be done outside. NOT INSIDE! There is a lot of percussion with this mixture. Could cause damage.

Away from fire sprinklers.

Provide warnings to neighbors or anyone in the building. With the large balloon it is a good idea to let dispatch know so you do not create a response.

DEMON #1 HYDROGEN & OXYGEN BUBBLES ON HAND

Equipment:

• Hydrogen gas cylinder with dual stage regulator, barbed fitting (Air Gas Linde or local gas supply)

• Oxygen cylinder

• Large balloon

• Bowl with dawn dish soap and glycerine and water. Mixt it up a bit.

• 5 gal. bucket of water

• BBQ lighter

• Fire extinguisher

• Ear plugs

• Folding table

Preparation:

1. Stage equipment and secure gas cylinders to ensure they do not tip over.

2. Use a table for the bucket of water and bubble solution. Use a fair amount of soap and glycerin. Glycerin will help make good bubbles.

3. Prepare to fill the balloon. Have students back up and use earplugs. Blow up the balloon (With your lungs) many times to it's full capacity to stretch it out and feel the balloon to see how tight it is near capacity. As you do the final fill you can see the size and feel the tension prior to it being too full.

4. Attach the regulator, ensure the regulator output (Balloon fill barb valve) is closed. Open the cylinder and check for leaks. The brass connections just need a snug fit to ensure there is good contact. Adjust the output to a minimal flow to fill a balloon.

5. This is the tricky part. Wrap the balloon opening around th barb fitting, you may have to fold it to make it tight. Open the fill valve and fill the balloon to to 65% full. Its a bit overfilled as you will loose a bit of gas filling the oxygen. Shut off the gas flow and close the cylinder.

6. Pinch the balloon with one hand then use the other hand to fit onto the threads of the oxygen cylinder or gas regulator, release the first pinch and seal it on the cylinder. Open the cylinder slowly and fill the balloon until it is almost full, check the tension of the balloon. Trying to get a 66.5/33.5 (H2O) mix. This may take a couple try's to make it right.

7. When full, turn off the oxygen cylinder.

Demonstration Instructions

1. You need 3 people for this demonstration

• • Participant or bubble holder

  • Lighter

  • Gas handler

2. Take the balloon and exhaust it into the liquid creating bubbles, you do not need a lot. A handfull will do.

3. Remove the balloon and keep it closed.

4. Have the participant remove any watches or other bracelets. Wedding rings are ok.

5. Have the participant dip their arm into the bucket of clean water up their elbow.

6. Have the participant scoop up some bubble with fingers together and hand slightly cupped.

7. Have the participant fully extend their arm arm (Ensure they have safety glasses and earplugs)

8. Tell the participant to flatten out their hand, keep fingers together away from the bowl.

9. Gas handler will remove ALL bubbles under hand and on wrist/arm area.

10. When ready have the lighter fully extend their arm and carefully light the bubbles from the top. No propane torches as it will blow through the bubbles and burn the skin and ignite the bubbles.

Observations:

THE WOW FACTOR! There is a significant amount of energy in this little package! The sound can be as loud as a 45 caliber gun.

Learning Outcomes:

• You can start off with the cylinders and talk about the hazard classes of flammable gases and oxidizers.

• Pressure of the cylinders, high or low? Cylinder markings for DOT, hydro dates, tare weights, compressed gas numbers (CGA) on valve and regulators, how a dual stage regulator works.

• You can show them how hydrogen alone makes a low thud sound (In a balloon) with more of a flowing yellow flame (Mostly due to the balloon). Hydrogen flames are difficult to see that's why many firefighters are trained to use thermal imaging cameras. In the old days a straw broom. You would slowly advance with the broom and if it lit the hydrogen flame was present.

• The addition of the oxidizer creates the perfect storm to balance the reaction. You can play around with mixtures but will find that the 66% Hydrogen to 33% Oxygen will be the loudest bang, H2O. Oxidizer can create a more flammable environment for combustible materials. You can talk about oil rags saturated with liquid oxygen, with sufficient impact will have a similar effect.

• This conversation can lead into liquid oxygen leaks and how dangerous they are when in contact with organic materials, like you! If you can complete the fire triangle you may be in trouble.

• Monitoring for hydrogen and its cross sensitivities on the carbon monoxide sensor.

• Monitoring for oxygen also.

• Mitigation techniques for each type of gas leak or if there was a mixture.

• Fuel cells that react hydrogen and oxygen to produce water, heat and electricity

Chemical Disposal:

Not much to dispose of it just makes water. Save for the Methane demo! Pour the soap and glycerin down the sink when done.

Additional Information:

DO NOT try this with other gases such as Acetylene or propane.

DEMONSTRATION #2 FULL BALLOON

All of the same safety precautions as above and equiipment. Some additional equipment is necessary.

Equipmenet (Additional)

• Vertal stand. Best to be about 4' tall. This can be a ring stand or makeshift stand as long as it is secure and will not send debris flying. An example could be a broom stick secured down the hole of a traffic cone. The broom stick will get a bit burnt.

• Hobby fuse, ~7 seconds per foot. Can be found at www.cannonfuse.com I like to use hobby fuse as it provides separation from the explosion.

• Electrical tape

• Lighter

Preparations

1. Stage all of the equipment in an open space like a parking lot. Secure the stand.

2. You need an assistant who will also have safety glasses and earplugs. Warn the assistant that the balloon can pop or explode at any time. I have had the balloon explode in close proximity once. I was fine, just very loud.

3. Take the hobby fuse and cut a section about 3' off the roll.

4. Start at the top of the stick and put a piece of electrical tape to secure the fuse at 2' below the top of the stick leaving a 6" tag line (Overhang).

5. Continue to tape the hobby fuse every 4 inches all the way down. The fuse likes to "Roll up" and could pop the balloon if too long of a tape distance is used.

6. Ensure there are no sharp edges at the top of the stand/stick.

Demonstration Instructions

1. Notify neighbors/dispatch they may hear a loud boom.

2. Fill the balloon with the correct ratios of gas. Tie it off in a knot.

3. Hold the balloon next to the top of the stand/stick and tape the tag end on the balloon carefully, secure it well as it will bounce around in the wind.

4. Advise the class you are lighting the hobby fuse.

5. Ensure all students are ~50 feet away from the balloon.

6. Wait....

Observations

LARGE KABOOM, CAR ALARMS GO OFF!!! Then you yell "Feel the Chemistry." That is if you got the mix correct. You can actually feel the slight pressure wave sometimes from a distance. Sometimes you don't get the mix right and have to do again. You will figure it out but slightly more hydrogen than oxygen most of the time.

Learning Outcomes

Same as above.

Chemical Disposal

None

Additional Information

This is the most dangerous experiment on the website.

Be careful!

Be Safe!

I have done this demonstration hundreds of times with great outcomes following safe protocols. It helps to have the balloon wet when the humidity is low, like fire conditions. Static electricity can set off the balloon, electrons move! Hydrogen activation energy is very low.