Definition
Thermometer
A thermometer is an instrument that measures temperature on a numbered scale or display.
What it means
On a scale thermometer, first find the value of each interval, then read where the liquid or pointer ends. On a digital thermometer, read the displayed number and its unit. Temperatures can be above or below zero.
Remember it
Find the interval, read the level, keep the degree unit.
Example
The marks from 20°C to 30°C are split into five equal intervals. Each interval is 2°C. A level three intervals above 20°C reads 26°C.
Watch for
Zero degrees is a temperature reading; it does not mean there is no temperature.
Common mix-up
A thermometer measures temperature, not how long something has been heating.
Exact meaning
A thermometer is an instrument for measuring temperature. Its reading is given as a number with a temperature unit, such as degrees Celsius (°C).