This is called rectification, and rectifier diodes are most commonly used in low current power supplies. A switching diode is most often used to turn a circuit on or off, and band switching diodes are used for switching high frequency band signals.
Thunder occurs when energy from lightning heats and rapidly expands the air. The resulting sound wave gets heard as thunder. While lightning and thunder occur at roughly the same time, lightning travels at the speed of light, or at 186,000 miles a second, while thunder travels at the speed of sound, equivalent to one-fifth of a mile in one second. People see the lightning long before they hear the thunder.
Lightning usually claims only one or two victims at a time and usually does not cause the mass destruction left in the wake of tornadoes or hurricanes. Lightning generally receives less attention than any other weather hazard. During a thunderstorm, each flash of cloud to ground lightning is a potential killer. However, lightning deaths can be prevented if people are aware of the dangers and seek shelter. Lightning can strike as much as 10 miles away from the rain area in a thunderstorm.