What Is Efficiency

There are no perfect machines—all machines produce waste energy.



C9.5 thermal image of high voltage power lines
There are limits to the amount of useful energy that can be formed from the conversion of potential energy to other forms in a technological device. With each energy conversion that occurs, more waste energy is produced, and therefore less useful energy is available.

Therefore, it is important to analyze the efficiency of energy transformations in a technological device, in order maximize the useful energy output. The next lesson in this section looks at how to calculate the efficiency of a device or system.

  Watch This

Bill Nye on Making His House Energy-Efficient © YouTube Wall Street Journal  


Watch this video for to see how Bill Nye has made his house energy-efficient to save money and to help the environment. He has implemented a number of devices and concepts discussed in this section of the physics unit so far.