How to Use a Glass Thermometer

Galileo invented the precursor to our modern glass thermometer approximately 400 years ago. Today, there are many forms of glass thermometers that are used in a number of industries, most notably in the sciences. They have also had the household use of checking human temperature orally. While thermometers for checking temperature can last longer and be more cost efficient than inexpensive digital thermometers they run the risk of causing injury. If the glass breaks, shards could injure the user. The mercury inside is also toxic, if it escapes the glass.

Things You'll Need

• Glass thermometer

Instructions

Using a Glass Thermometer

1. Rinse the thermometer under cold water.

2. Grasp the opposite end of the thermometer that the mercury is in (mercury is liquid-like ball inside the thermometer). Snap your wrist to shake mercury down. The temperature should be below 95 degrees Fahrenheit.

3. Insert thermometer into a protective sheath, if you are using one. This is not necessary, but is a common practice in hospitals and/or doctors offices.

4. Place thermometer under the tongue and hold it there for three minutes with mouth closed.

5. Remove thermometer and hold it up to the light to see the temperature. The number that corresponds to the placement of mercury is the temperature. If you wish, record the time and temperature. The human body's healthy temperature is 98.6 degrees Fahrenheit. Any higher, the person is considered to have a fever.

6. Clean the thermometer using soap and lukewarm water. You can add isopropyl alcohol after washing to further disinfect.

Tips & Warnings

• Do not place thermometer in drastically different temperatures successively. Glass will break if moved from cold directly to hot temps, and vice versa.

References

• Municipality of York: How to Use a Thermometer
• Omega.com: Glass Thermometers: A Degree of History

Resources

• "A History of the Thermometer and Its Use in Meteorology"; W.E. Knowles Middleton; 1966