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Alcohol Thermometer vs. Mercury Thermometer: What's the Difference?

Edited by Janet White || By Harlon Moss || Updated on October 10, 2023
Alcohol thermometers use alcohol to measure temperature, safe but less accurate; mercury thermometers use mercury, precise but toxic if broken.

Key Differences

Alcohol thermometers leverage the expansive and contractive property of alcohol, making them suitable for various applications. Mercury thermometers utilize mercury's thermal expansion, renowned for its precision and consistent reliability in measurements. While both thermometers serve the fundamental purpose of measuring temperature, they do so utilizing different mechanisms and materials.
Alcohol thermometers are typically used where safety is a priority, owing to the non-toxic nature of alcohol. On the other hand, mercury thermometers pose a risk of toxic exposure if broken, thus requiring careful handling and disposal. Though alcohol and mercury thermometers can both be used across numerous applications, the latter often finds usage where high accuracy is paramount due to its stable, uniform thermal expansion.
Alcohol thermometers often exhibit vibrant colors, making readings clear and visually appealing, especially beneficial in educational contexts. Mercury thermometers, by contrast, display a silvery liquid, which may be less vibrant but is often associated with traditional, high-precision temperature measurement. Both thermometers visually represent temperature changes, though with distinct aesthetic appearances.
Alcohol thermometers may present a larger operational temperature range due to alcohol’s lower freezing point compared to mercury. Meanwhile, mercury thermometers might be limited to environments where the substance remains in a liquid state, ensuring accurate measurements. The operational ranges of alcohol and mercury thermometers hence define their suitability for diverse climatic conditions.

Comparison Chart


Alcohol begins with a vowel
Mercury begins with a consonant


Alcohol thermometer has 6 syllables
Mercury thermometer has 6 syllables

Common Abbreviations

None widely recognized
Hg thermometer (Hg is symbol for mercury)

Associated Adjectives

Often described as "safe" or "colored"
Often described as "accurate" or "toxic"

Use in Sentences

Usually a standalone object
Sometimes used with "old-fashioned" or "traditional"

Alcohol Thermometer and Mercury Thermometer Definitions

Alcohol Thermometer

Alcohol thermometers are known for their vibrant, colored fluid.
I could easily read the bright red level of the alcohol thermometer from a distance.

Mercury Thermometer

The mercury thermometer operates effectively within its liquid state temperature range.
The mercury thermometer failed to register the extreme cold due to mercury solidifying.

Alcohol Thermometer

An alcohol thermometer is often chosen for its non-toxic properties.
Schools prefer using an alcohol thermometer to avoid mercury spills in the classroom.

Mercury Thermometer

Mercury thermometers often have a silvery column to indicate temperature.
The silvery column of the mercury thermometer dipped as the night grew colder.

Alcohol Thermometer

Alcohol thermometers typically have a wide operational temperature range.
The alcohol thermometer displayed temperatures accurately, even in the freezing outdoors.

Mercury Thermometer

The mercury thermometer contains mercury, which is toxic when exposed to air.
Breaking a mercury thermometer requires careful clean-up to avoid toxic exposure.

Alcohol Thermometer

The alcohol in an alcohol thermometer can be dyed various colors for visual appeal and clarity.
The blue liquid in the alcohol thermometer sank as the air temperature dropped overnight.

Mercury Thermometer

A mercury thermometer uses mercury, a metallic liquid, to gauge temperature.
The old mercury thermometer read a steady 22 degrees Celsius in the room.

Alcohol Thermometer

An alcohol thermometer uses alcohol as its thermometric fluid.
The science kit included an alcohol thermometer for safe experimentation by kids.

Mercury Thermometer

Mercury thermometers are prized for their accuracy and reliability.
Physicians often relied on a mercury thermometer for precise body temperature readings.


What fluid is used in an alcohol thermometer?

An alcohol thermometer uses dyed ethanol or other alcohol.

What is the main advantage of using a mercury thermometer?

Mercury thermometers are known for their high accuracy and reliability.

What colors are usually seen in alcohol thermometers?

Alcohol thermometers commonly utilize red or blue dyed alcohol.

Where is the mercury in a mercury thermometer located?

The mercury is contained within a small, sealed glass tube.

Why are mercury thermometers becoming less common?

Due to mercury’s toxicity, many prefer safer alternatives like alcohol thermometers.

How does an alcohol thermometer respond to temperature changes?

The alcohol expands or contracts, moving up or down a graduated scale.

How are mercury spills from mercury thermometers handled?

Mercury spills require careful handling and clean-up due to its toxicity.

What happens when a mercury thermometer breaks?

Mercury is released, which is toxic and requires safe cleanup procedures.

Are mercury thermometers still used in medical settings?

Usage has declined due to safety concerns, but they might be used where high accuracy is crucial.

Can a mercury thermometer be used in extremely cold temperatures?

No, mercury thermometers are limited by mercury's freezing point (-39°C or -38°F).

How is temperature read on a mercury thermometer?

By observing the height of the mercury column along the calibrated scale.

Is an alcohol thermometer environmentally friendly?

Generally yes, as it does not contain toxic substances like mercury.

What is the typical maximum temperature an alcohol thermometer can measure?

Typically, up to 78°C (172°F), depending on the specific type and design.

Is it difficult to read an alcohol thermometer?

No, they often have brightly colored alcohol for easy reading.

Is a mercury thermometer safe for home use?

While accurate, its usage is often avoided in homes due to breakage and toxicity risks.

Are mercury thermometers illegal?

In some regions, yes, due to environmental and health concerns regarding mercury.

Can alcohol thermometers measure very high temperatures?

Generally, alcohol thermometers are not suitable for extremely high temperatures.

Is an alcohol thermometer suitable for science experiments?

Yes, they're often used in educational settings due to their safety.

Is the alcohol in alcohol thermometers dangerous?

Generally, no, alcohol in thermometers is considered safe and non-toxic.

Can I use an alcohol thermometer for medical purposes?

Yes, but they might be less precise than mercury thermometers for medical readings.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.

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