SI unit of power, equal to one joule per second
named after James Watt, who improved the steam engine
measures the rate of energy transfer or conversion
1 horsepower ~ 746 watts
human basal metabolic rate: ~80 watts
typical household light bulb: 10-100 watts
Sun luminosity: 3.846e26 watts
kilowatt (kW) for appliances, megawatt (MW) for power plants, gigawatt (GW) for national grids
electrical power: P = volt times ampere (voltage times current)