The term high voltage characterizes electrical circuits, in which the voltage used is the cause of particular safety concerns and insulation requirements. High voltage is used in electrical power distribution, in cathode ray tubes, to generate X-rays and particle beams, to demonstrate arcing, for ignition, in photomultiplier tubes, and high power amplifier vacuum tubes and other industrial and scientific applications.

Skateboarding is the act of riding and performing tricks using a skateboard. A person who skateboards is most often referred to a skateboarder, skater or skate rat.

Skateboarding can be a recreational activity, an artform, a job, or a method of transportation. Skateboarding has been shaped and influenced by many skateboarders throughout the years. A 2002 report by American Sports Data found that there were 18.5 million skateboarders in the world. 85 percent of skateboarders polled who had used a board in the last year were under the age of 18, and 74 percent were male.

Skateboarding is relatively modern. A key skateboarding maneuver, the ollie, was developed in the late 1970s by Alan "Ollie" Gelfand as a half-pipe maneuver. Freestyle skateboarder Rodney Mullen was the first to take it to flat ground and later invented the kickflip and its variations.