How to Read Temperature Gauges

A thermometer is one type of temperature gauge.

Temperature gauges, such as thermometers and thermostats, are used in a wide variety of applications. Their main purpose is to provide you with information about how hot something is, usually measured in degrees Fahrenheit or Celsius. In the case of thermostats, the gauges are programmed to turn an appliance like a refrigerator or heater on or off when a certain temperature is reached.

Instructions

1. Place the temperature gauge (a thermometer in this example) in the area in which you want to measure temperature. For example, this can be underneath a person's tongue to measure his or her body temperature, or outside to measure the air temperature.

2. Leave the thermometer in the location for about 5 minutes and allow the gauge to adjust to the temperature.

3. Read the thermometer. If it's a digital thermometer, the screen will display the temperature by showing a number. With some analog thermometers, a needle will move and point to a an area on which the corresponding temperature is labeled. Other analog thermometers use mercury in a glass or plastic vial. Match the top of the mercury to the label on the side of the vial to read the temperature.

4. Round the temperature up or down to the nearest degree if the thermometer provides a reading between two lines. For instance, if the marks on the thermometer are in increments of one and there is a reading between 72 and 73 degrees, record the temperature as 72 degrees if gauge is closer to the 72-degree mark. Thermometers marked with five lines measure to 2/10 (.2) of a degree. For example, if the gauge reads at the second mark after the 72-degree mark, the temperature is 72.4 degrees Fahrenheit (72 degrees, plus 4/10 degrees).

5. Tilt a glass mercury thermometer when reading it. These thermometers are designed with flat areas that magnify the mercury to make it easier to read. Rotate the thermometer until the mercury is clearly visible, then record the temperature.

Tips & Warnings

• Placing the thermometer in direct sunlight or over an area which attracts heat (such as asphalt) can give the thermometer an artificially high reading.

References

• Reach Out Michigan: How to Read a Thermometer
• NSTA: How to Read a Thermometer
• Sweet Haven Publishing Services: Taking Vital Signs--Lesson 2--Temperature