$\require{mhchem}$

A spark from a Tesla coil is used to ignite ethanol vapor in a bottle, propelling a cork upward. Exciting! 

Curriculum Notes 

This is pretty much an all purpose demo for introducing reactions in general, oxidation, combustion, or thermochemistry. Allow about 5 minutes for this demo.

One day of lead time is required for this project.

Discussion 

The high-voltage, high frequency electricity emitted by the Tesla coil arcs to the nail, producing a spark. The current then arcs from that nail to the other nail, producing a spark inside the bottle, which ignites the ethanol/air mixture.

$\ce{C2H5OH(g) + 3O2(g) -> 2CO2(g) + 3H2O(g)  }$

Materials 

• plastic juice bottle with cork to fit
• Tesla coil
• wash bottle with ethanol in it.
• blast shield

Procedure 

Spray about a couple of milliliters of ethanol into the bottle, replace the stopper, and roll the liquid around to coat the inside of the bottle. Place the bottle, pointing upward, in the middle of the table. Plug in the Tesla coil and turn the knob on the end clockwise until you hear a crackling sound as the probe begins to ionize the air around it. Dim the house lights. Holding the Tesla coil at arms length, bring it close to one of the nails protruding from the side of the bottle. Sparks will jump between the coil and the nail and between the two nails. Theethanol/air mixture inside the bottle will explode, propelling the stopper skyward. Turn the knob on the Tesla coil counter-clockwise until the crackling stops and unplug it.

Safety Precautions 

• Wear goggles when performing this demonstration.
• The stopper is ejected from the bottle very rapidly. It may strike objects above it and bounce back down. Make sure there is a clear path above the bottle. Make sure that the bottle is pointing straight up.
• No students should be seated nearer than five meters from the demonstration.
• Ethanol is flammable. Move the bottle of ethanol away from the demo once you are finished using it.
• No flammable objects should be in the vicinity of the demonstration. Know the location of the nearest fire extinguisher.
• The Tesla coil probe produces high-voltage, high frequency electrical current. Do not bring it near anyone's body as it is capable of arcing through the air and shocking and burning them.
• No one with a pacemaker should handle a Tesla coil.
• Perform all operations behind the blast shield.