with different glass shapes and integrated-circuit-driven electronics, create the vivid colors, range of motions, and complex patterns seen in today's plasma spheres. Applications Plasma balls are mainly used as curiosities or toys for their unique lighting effects and the "tricks" that can be performed on them by users moving their hands around them. They might also form part of a school's laboratory equipment for demonstration purposes. They are not usually employed for general lighting. However, in recent years, some novelty stores have begun selling miniature plasma ball nightlights that can be mounted on a standard light socket. Plasma balls can be used for experimenting with high voltages. If a conductive plate or wire coil is placed on the ball, capacitive coupling can transfer enough voltage to the plate or coil to produce a small arc or energize a high voltage load. This is possible because the plasma inside the ball and the conductor outside it act as plates of a capacitor, with the glass in between as a dielectric. A step-down transformer connected between the plate and the ball's electrode can produce lower-voltage, higher-current radio frequency output. Careful earth grounding is essential to prevent injury or damage to equipment. Hazards Bringing conductive materials or electronic devices close to a plasma ball may cause the glass to become hot. The high voltage radio frequency energy coupled to them from within the ball may cause a mild electric shock to the person touching, even through a protective glass casing. The radio frequency field produced by plasma balls can interfere with the operation of touchpads used on laptop computers, digital audio players, cell phones, and other similar devices. Some types of plasma ball can radiate sufficient radio frequency interference (RFI) to interfere with cordless telephones and Wi-Fi devices several feet or some meters away. If an electrical conductor touches the outside of the ball, capacitive coupling can induce enough potential on it to produce a small arc. This is possible because the ball's glass acts as a capacitor dielectric: the inside of the lamp acts as one plate, and the conductive object on the outside acts as the opposite capacitor plate. This is a dangerous action that can damage the ball or other electronic devices, and presents a fire ignition hazard. Perceptible amounts of ozone can be formed on the surface of a plasma ball. Many people can detect ozone at concentrations of