Difference Between Digital and Glass Thermometer | Science Equip

A thermometer is mostly associated with the measurement of fever. However, when it comes to science laboratories, a thermometer is used for various purposes like measuring the temperature of liquids, foods, air, etc. 

The two most common types of thermometers are mercury and digital. Let's understand the difference between the two.

Mercury Thermometer

This is a glass thermometer, one of the most traditional ways to take the temperature. It contains mercury, a dense poisonous metal. The reading is based on the natural chemical reaction between mercury and temperature. You can read the temperature by observing where the bar stops on the standard temperature scale marked on the tube.

Pros:

A mercury thermometer can resist boiling and freezing temperatures without breaking.

Cons: 

• Mercury is toxic. You need to handle it with care. 
• Being made of glass, mercury thermometer is fragile and can break easily. 
• If mercury falls on the ground, it spreads all over the surface, creates hazardous conditions, and is difficult to clean.
• It takes time to give the reading.
• It has a low thermal co-efficient.

Digital Thermometer

A digital thermometer has become a more popular choice than a mercury thermometer. It has a heat sensor that can identify the temperature and display the reading on a digital screen. It works through metal probes and voltage. They use batteries and hardly require any charging.

Pros:

A digital thermometer is simple and convenient to use.

• It gives faster results than a mercury thermometer which usually takes time to heat up.
• It is safer as it doesn't contain any harmful chemicals.
• It gives more precise results than a mercury thermometer.

Cons:

You to keep additional batteries handy just in case the digital thermometer runs out of power.

• If the batteries are about to die, then the results may not be accurate.
• It is difficult to predict when the battery needs replacement.
• A digital thermometer is difficult to clean as water can mess with its mechanical system.

Which is Better – Mercury or Digital Thermometer?

It isn't easy to give a verdict in favor of any of these two thermometers. Both have their distinct features, advantages, and disadvantages. However, mercury thermometers are more commonly used as laboratory glassware these days. Digital thermometers are gradually replacing mercury thermometers, especially in household and industrial applications.

The choice of thermometer depends on the purpose you use it for and the level of accuracy you want.