Energy describes an amount transferred or used; power describes the rate of that transfer. A device can draw a modest amount of power over a long period and still use a meaningful amount of energy.
Read both the quantity and its unit when comparing information about a device. Watts describe power, while watt-hours describe energy. A rating alone may not tell you the consumption during a particular task or under a particular setting.
Use the manufacturer’s documentation to understand the figures relevant to ordinary use. Keep the task and duration beside the comparison. The distinction between an amount and a rate turns an appealing single number into a more useful question about what the device actually does.
An example to consider.
Imagine two lamps used for different lengths of time. Their power ratings describe a rate, while the duration helps determine the energy used.
Put it in perspective.
An observation has a method behind it. Keep the instrument, conditions, and comparison close to the result so another reader can understand what was measured.
- Distinguish an amount from a rate.
- Read the unit beside the number.
- Keep the task and duration in the comparison.
Follow a related question
Record the support behind the pilot.
From a pilot to an ordinary dayPick an everyday digital action.
The small details of digital lifeKeep learning
Related background to continue exploring this subject.
NASA: science learning resources NIST: the International System of Units
