How does an e-cigarette work?
Answer:
Pressing the battery's fire button closes the electronic circuit from the battery to the vaporizer. The vaporizer contains a small metal wire (hence the name "coil") that heats up with the force applied. This wire is wrapped in a material called a wick, which absorbs the liquid from the tank. This wick is often made of cotton or silica. When the wire is heated, the absorbed liquid is converted into vapor. Most new (pod-)systems no longer require a button; the system is activated by inhalation force, so there's no need for a fire button.