How to Use a Mercury Thermometer

Do you know How to Use a Mercury Thermometer? In a mercury-in-glass thermometer, a glass tube is crammed with mercury, and a typical scale is marked on the tube.

How to Use a Mercury Thermometer

With temperature changes, the mercury expands and contracts, and therefore the temperature is often read from the size.

Mercury thermometers are often wont to determine body, liquid, and vapor temperature. Mercury thermometers are utilized in households, laboratory experiments, and industrial applications.

Accurate body temperature readings can make a difference in treatment decisions. Using a mercury thermometer is easy but requires a bit of practice and skill.

Mercury Thermometer

A mercury thermometer is a type of thermometer that uses the thermal expansion of mercury to measure temperature. It consists of a glass tube with a bulb at one end containing mercury, and a calibrated scale marked on the glass tube.

When the thermometer is exposed to a change in temperature, the mercury expands or contracts, causing it to rise or fall in the tube. The temperature is read by observing the position of the mercury column on the scale. Mercury thermometers were widely used in scientific, medical, and industrial applications in the past, but they are now being phased out due to the potential health hazards associated with the use of mercury.

How to Use a Mercury Thermometer

Mercury thermometers are designed to measure temperature accurately, but they require proper handling and care due to the toxic nature of mercury. While many places have phased out the use of mercury thermometers in favor of digital or safer alternatives if you have one and need to use it, here’s how to do it safely:

Check for damage: Inspect the thermometer for any cracks or damage to the glass. If you notice any, do not use it, as it may release mercury vapor.

Wash your hands: Before handling the thermometer, wash your hands thoroughly with soap and water. This will help prevent contamination.

Shake it down: Hold the thermometer at the top (the end opposite the bulb) and flick your wrist to force the mercury down to the bulb. This ensures that the thermometer is ready for use.

Place the thermometer: Place the bulb end of the thermometer where you want to measure the temperature. Keep it in position for at least 2-3 minutes to allow the mercury to reach thermal equilibrium and give an accurate reading.

Read the temperature: Hold the thermometer at eye level and read the temperature where the mercury level in the tube stops. Be cautious, as the mercury level may fluctuate slightly as you read it. The temperature is typically measured in degrees Celsius (°C) or Fahrenheit (°F), depending on the scale used on the thermometer.

Record the temperature: Once you have taken the reading, record the temperature, and be sure to do so accurately.

Handle with care: After use, carefully wipe the thermometer clean with a tissue or a cotton ball. Make sure to wash your hands thoroughly again after handling it. Do not rinse the thermometer under running water or use alcohol wipes to clean it, as this can damage it.

Store safely: Store the mercury thermometer in a protective case or container to prevent breakage. Store it in a cool, dry place away from direct sunlight. Keep it out of reach of children and pets.

Dispose of responsibly: When it comes time to dispose of a mercury thermometer, it should be handled as hazardous waste. Contact your local hazardous waste disposal facility for guidance on proper disposal. Do not throw it in the regular trash or down the drain.

Reading a Glass Mercury Thermometer

Because different models may have slightly different reading methods, one should first read manufacturer directions that come with all mercury thermometers. The following are general guidelines for many of the mercury glass thermometers:

1. Standard precautions like washing hands and wearing gloves if appropriate

2. Handle with care to prevent the thermometer from chipping or breaking

3. Remove the probe cover and/or wipe the thermometer with dry tissue from the stem to the bulb. Do not use an alcohol swab before reading the temperature reading

4. Remove the cover. Wipe the thermometer with dry tissue from the stem to the bulb. Do not use alcohol swabs before reading the temperature

5. Hold the thermometer at eye level and parallel to the floor

How to Read a Mercury Glass Thermometer?

Reading a Mercury Glass Thermometer properly is important, both in reception and the hospital. Accurate checking of blood heat is significant for determining the course of treatment or medication.

One should read the mercury-in-glass thermometer immediately after taking the temperature. The temperature should be read to the closest line.

In a Fahrenheit Thermometer:

1. Long lines indicate 1 degree

2. Short lines indicate 0.2 degrees

3. While in a Celsius thermometer

4. Long lines indicate 1 degree or 0.5 degrees

5. Short lines indicate 0.1 degrees

Most Mercury-in-glass Thermometers

One should be careful while reading temperatures between 100 degrees and 101 degrees because many people mistakenly record or report a tenth of a degree as a whole degree.

For example, 100.2 degrees is between 100 and 101 while 102 degrees is between 102 and 103. Avoid mistakes because it could end in inappropriate therapy.

1. Read the Mercury Thermometer at Eye Level

2. Long lines on the Fahrenheit scale indicate 1 degree

3. Short lines on the Fahrenheit scale indicate 0.2 degree

4. Read the Celsius scale to the nearest 0.1 degree

5. Read temperature to nearest lines

After taking the temperature, hold the thermometer up to a light where you can see the mercury line and the numbers. Rotate the thermometer until you can see the number and the lines between the numbers, much like on a ruler.

How to Check a Temperature Under the Tongue (Orally)?

Shakedown the mercury with a glass thermometer before placing it under the tongue. Do this by holding the thermometer firmly and flicking the wrist until the mercury reads at or below the rock bottom number.

Ensure the thermometer is far away from people and objects before shaking. Now, place the bulb end of the thermometer under the tongue and ask the person to shut his mouth and breathe through his nose. The thermometer must stay under the tongue for a minimum of a moment to 2 minutes.

When an Oral Temperature should not be taken?

1. Infant or child

2. Injured or bleeding orally

3. Unable to shut the lips or had surgery within the mouth recently

4. Experiencing chills or rigors or if her teeth are chattering

5. Having difficulty breathing or receiving oxygen via a mask

6. Using a nasogastric tube for feedings

7. Unable to take commands, confused, combative, or uncooperative

8. Unconscious or not responsive or on seizure precautions

DP20 – Mercury Basal Thermometer (°F)

Note: Basal thermometers are different from regular fever thermometers and used only by WOMEN to notice basal blood heat that happens with ovulation.

NET Basal mercury-in-glass thermometer is an accurate device to chart the basal blood heat of girls to predict their fertile phase or ovulation.

A basal thermometer, thus, helps women determine when they ovulate and thereby dramatically increases the chances of conceiving and falling pregnant. In this way, they can plan either to conceive or take precautions.

A woman is vulnerable to conception during 3 days of ovulation and the NET Basal mercury-in-glass thermometer can indicate lately.

With ovulation, body temperature increases due to an increase in the hormone progesterone, and by a precise recording of your body’s resting temperature first thing in the morning and at the same time each morning, you can know when ovulation takes place in your cycle. Made from top quality capillary with lens front in Jena normal glass. Suitable for oral (sub-lingual) and rectal use.

Temperature Range: 95° – 100°F Subdivided in 0.1°F

Household Uses of Mercury Thermometers

Common household uses of mercury thermometers include fever thermometers and oven, candy, and meat thermometers.

Fever Thermometers

Mercury fever thermometers are made of glass the size of a straw, with a silvery-white liquid inside. They are common in many households, schools, and medical facilities. Two general sorts of mercury thermometers measure body temperature:

Oral/Rectal/baby thermometers, containing about 0.61 grams of mercury` Basal temperature thermometers (used to track slight changes in body temperature), containing about 2.25 grams of mercury

Is There Mercury in My Thermometer?

1. If there is no liquid in your thermometer, for example, if it uses a metallic strip or coil to measure temperature, it is not a mercury thermometer

2. If the liquid in the thermometer bulb is any color other than silver, it is not a mercury thermometer

3. If the liquid in your thermometer bulb is silver, then the liquid might be Mercury or A non-toxic compound that looks similar to mercury.


What is a mercury thermometer?

A mercury thermometer is a type of thermometer that uses mercury as the thermometric fluid to measure temperature.

How does a mercury thermometer work?

The thermometer has a glass tube with a small bulb at one end that contains mercury. As the temperature changes, the mercury expands or contracts, moving up or down the tube, indicating the temperature.

What are the advantages of a mercury thermometer?

Mercury thermometers are very accurate and provide a stable and consistent reading. They are also durable and long-lasting.

What are the disadvantages of a mercury thermometer?

Mercury is a toxic substance, and if a thermometer breaks, the mercury can be released into the environment, posing a health risk. They are also more fragile and prone to breaking than digital thermometers.

Are mercury thermometers still used?

Mercury thermometers are becoming less common due to their potential environmental and health hazards. Digital thermometers are now more popular due to their accuracy and ease of use.

How should I dispose of a mercury thermometer?

Mercury thermometers should be disposed of at a hazardous waste facility or through a special collection program. Do not throw them in the regular trash. If a mercury thermometer breaks, follow appropriate cleanup procedures to avoid exposure to mercury vapor.

Can I still buy a mercury thermometer?

In many countries, including the United States, the sale of mercury thermometers has been banned or restricted. However, they may still be available for certain applications, such as in laboratory settings.

Final Words

Reading a Mercury Glass Thermometer properly is important, both in reception and the hospital. Accurate checking of body temperature is vital for determining the course of treatment or medication.

One should read the mercury thermometer immediately after taking the temperature. The temperature should be read to the closest line.

We also have a detailed review on Normal Baby Temperature Armpit in case if you want to check that out! and other articles.

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