# Woosh Bottle

Required Training

Required PPE

UC Lab Safety Fundamentals

Flame-resistant lab coat, safety glasses/goggles,

hearing protection, nitrile gloves

Performers Required: 1

Equipment

Chemicals

Dry polycarbonate bottle (5 gallon)

Methanol (CH3OH)

Stand for bottle

Ethanol

Rubber stopper (to fit bottle)

Propan-1-ol

Tissue fixed to a 1-meter stick/pole

Propan-2-ol

Procedure:

1.) A clean dry bottle is required for each reaction (1 bottle = 1 alcohol). The ignition site should be 5 feet away from flammable materials (such as the alcohols).

2.) Fill a beaker with 40 mL of selected alcohol then transfer to the bottle. Insert the rubber stopper and roll the reaction vessel on its side for 10 seconds, to and fro, allowing the alcohol to vaporise and the vapor to fill the vessel.

3.) Pour any surplus liquid alcohol back into the beaker, draining the bottle as completely as possible. Excess liquid may results in igniting the bottle itself. Ensure any alcohol or flammable material is removed from the area by 5 feet.

4.) Stand the bottle inside of the stand, ensure a tight, secure fit then remove the stopper. Light the tissue affixed to the pole and apply the lighted end to the open next of the bottle. It is dangerous to ignite by dropped a lighted match into the vessel when using ethanol or methanol, and in general should be avoided even with additional safety measures.

5.) The alcohol vapor should ignite with a loud ‘woosh,’ with flames shooting out of the top of the vessel no greater than 6 inches.

Clean-up: Leave the bottles upright for several days until completely dry.

Hazards: Methanol is toxic and highly flammable. Ethanol, propan-1-ol and propan-2-ol are flammable and harmful/irritants. If the bottle is not secured it may tip over, therefore it is critical to have a well-fitting stand and remove any excess liquid in case of spillage. Igniting the vapor results in heat and fire, the bottle may be warm to handle afterwards. Hazards include thermal burns from the fire. If the water bottle is not made of polycarbonate it can be prone to combustion or explosion.

Principle: Alcohols with low boiling points vaporize readily and in enclosed spaces forms a volatile mixture with air (the critical component being oxygen). Alcohols are heavier than air, so even when the bottle is opened it will remain inside for some time. The fire provides the activation energy required for the combustion of the alcohol and oxygen. In the vapor form, alcohol molecules are farther apart than in the liquid phase, presenting more surface area which in turn causes the combustion reaction to occur faster. Using different alcohols will result in different flame colors and timing. Ethanol and methanol are short chain alcohols and burn very quickly with a blue flame. Propan-1-ol and propan-2-ol are longer chain alcohols and burn slightly slower with blue and yellow flames. The woosh sounds results from the rapid burning in a confined space with a small outlet (the bottleneck).

$$(CH_3)_2CHOH(g) + \frac{9}{2}O_2 \rightarrow 3CO_2(g) + 4H_2O(g) ∆H = –1886.6 kJ/mol)$$