Self-made piezoelectric igniter from an empty cigarette lighter   
Piezoelectric cigarette lighters use piezoelectric igniters ("piezo") to ignite the liquid gas (Photo 1). When the fuel is consumed this device can be removed and re-used to assemble an igniter for eudiometer experi-ments. "Piezoelectricity is the ability of some materials ..... to generate an electric potential in response to applied mechanical stress....If the material is not short-circuited, the applied charge induces a voltage" of up to 15.000 Volt. This gives rise to electric conductivity of air. The right Photo shows a young student with 20 piezo divices he has assembled in 2 hours.
Material
Tray, empty piezoelectric cigarette lighter, small board ( 5 x 5 x 2 cm), saw, drilling machine with a drill in the diameter of the piezo metal cylinder, 6 cm of insulated copper wire (D 0.8 mm), pincers, knife, glueing pistol.
Procedure
1. Saw a small board from a remnant of wood obtainable from a carpenter.
2. Drill a hole into the middle of this board. Its diameter should be the same like the one of the piezo metal cylinder. (Photo 2).
3. Cut off 0.5 cm of insulation at the wire ends of piezo and of the second wire. At the other end of the second wire remove 1,5 cm of insulation.
4. Bend the long end of the second wire like seen in Photo 2.
5. Press the bended wire and the metal cylinder of the piezo into the hole of the board, fix it with liquid glue from the pistol (Photo 3).
6. Bend the bare wire ends to a distance of 1 cm. Press the button down strongly.
Observation
A flash of lightning jumps from the end of one wire to the other one.
Explanation 
The high voltage between the bare wire ends is high enough to ionize the molecules of the air. In a split second an electric circuit is closed.

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back................first publication: 29.12.2007...........................................last modification: 17.10.2008