watt

Examples of watt in the following topics:

• Boulton and Watt

• Solar power

  • Power from the first solar cells, for example, cost about $200 per watt.
  • In 2007, the price was $2.70 per watt (before payback) and in 2012, in Germany, the cost (minus installation fees) was $1.34 per watt (before payback).

• What is Power?

  • The unit of power is the joule per second (J/s), known as the watt (in honor of James Watt, the eighteenth-century developer of the steam engine).
  • For example, the rate at which a lightbulb transforms electrical energy into heat and light is measured in watts (W)—the more wattage, the more power, or equivalently the more electrical energy is used per unit time .

• References

  • ., Watts, D., Croston, J., Durkin, C. (2002).

• Energy Policy

  • Incoming solar radiation to the Earth equals 341 watts per square meter (Trenberth et al., 2009).
  • Some of the solar radiation is reflected back from the Earth by clouds, the atmosphere, and the Earth's surface (102 watts per square meter).
  • About half of the solar radiation is absorbed by the Earth's surface (161 watts per square meter).
  • Solar radiation is converted to heat energy, causing the emission of longwave (infrared) radiation back to the atmosphere (396 watts per square meter).
  • Outgoing infrared radiation from the Earth equals 239 watts per square meter.

• Intensity

  • The SI unit for intensity is watts per meter squared or,$\frac W{m^2}$.
  • Although the units for sound intensity are technically watts per meter squared, it is much more common for it to be referred to as decibels, dB.

• Psychosurgery

  • Watts devised what became the standard prefrontal procedure and named their operative technique "lobotomy."
  • Watts study an X-ray before a psychosurgical operation.
  • Freeman and Watts developed a lobotomy technique that became the standard.

• Present Sources of Energy

  • The amount of energy the sun provides has been measured by satellite to be roughly 1368 watts per square meter, although this amount fluctuates by about 6.9% during the year due to the Earth's varying distance from the sun.
  • This value represents the total rate of solar power received by the planet, although only about half, 89 PW (PW = petawatt, which is equivalent to 1015 watts; a watt is equal to J/s), reaches the Earth's surface.

• Steps to Integrating Experiential Learning in the Classroom

  • It was found that many of these courses did not allow for concrete experience and active experimentation due to the fact that the learning processes were based on more traditional learning methods and not capitalizing on the self-directed nature of the learners (Friedman, Watts, Croston, & Durkin, 2002).

• Recycling

  • Recycling a plastic bottle saves enough energy to power a 60 watt light bulb for three hours.