Why is mercury and alcohol used in thermometers instead of water?

There is a technical reason for using mercury in clinical thermometers. Mercury has a greater coefficient of thermal expansion than alcohol. This means a column of mercury will expand and rise more than a column of alcohol for the same temperature change. As a result, you can get finer readings with mercury.

Why water is not used in thermometer instead of mercury?

Water is not able to be used as a thermometer liquid because of its higher freezing point and lower boiling point than the other liquids in general. This range is very negligible as compared to other liquids like mercury which has a freezing point of about −39∘C and boiling point 356∘C.

Why is alcohol used instead of water in a thermometer?

Alcohol is favored over water for the simple reason that it boasts a higher coefficient of expansion. Mercury has a higher coefficient of expansion than water, which means that changes in its volume with temperature are more noticeable. However, its value is almost six times less than that of alcohol.

Why are liquids used in thermometer?

It is because the liquids like mercury and alcohol expand uniformly on increasing temperature and also contracts uniformly on decreasing the temperature. So, it gives us the accurate measure of the temperature. That’s why liquids are used in the thermometer not solids or gases.

What happens to the liquid in a thermometer when the temperature gets warmer?

When heated, the molecules of the liquid in the thermometer move faster, causing them to get a little further apart. This results in movement up the thermometer. When cooled, the molecules of the liquid in the thermometer move slower, causing them to get a little closer together.

Can we use water in place of mercury?

Water can’t be used in place of mercury in a barometer because of its low density. It would require a 10.34 m long tube to measure 1 atmospheric pressure which is not practically possible while mercury having high density (13.6 g/cc) would require only 0.76 m long pipe which is practically possible.

Why is alcohol not used in clinical thermometer?

Alcohol is not used in a clinical thermometer. It cannot measure the high temperatures because of its low boiling point. Mercury is used in a clinical thermometer. Alcohol is used in a laboratory thermometer instead of a clinical thermometer.

Under what conditions is it better to use alcohol instead of mercury in a thermometer?

Explanation: The freezing point of mercury is approx -39°C and that of alcohol is -114°C. Therefore, in areas of extreme cold conditions, alcohol thermometer is better to use than mercury thermometer.

Why liquids are used in thermometer but not the solid?

Liquids are used in thermometers because they expand and contract with temperature changes and they take on the shape of a container without filling it. Solids do not work in thermometers because they do not take on the shape of the container.

Why does liquid in the thermometer?

The liquid in the thermometer goes up when the thermometer is heated because heating makes the alcohol molecules of the liquid move faster. The extra speed of the molecules competes with their attraction for one another and causes them to move slightly further apart.

How does the liquid in a thermometer work?

A thermometer has a glass tube sealed at both ends and is partly filled with a liquid like mercury or alcohol. As the temperature around the thermometer’s bulb heats up, the liquid rises in the glass tube. When it is hot, the liquid inside the thermometer will expand and rise in the tube.

Why is mercury red in thermometers?

Silver liquid indicates that the thermometer contains mercury, while red liquid is alcohol to which red coloring has been added. Although uncommon in modern thermometers, a clear color indicates water.

Why do thermometers have mercury in them?

If you have a thermometer that has a silver-looking liquid, your thermometer contain mercury. Because mercury is dangerous if you spill it, most thermometers today use alcohol colored with a red dye. Alcohol has a lower freezing point than water.

Why don’t thermometers use alcohol instead of water in them?

Alcohol has a lower freezing point than water. Also, real thermometers don’t use water inside because water doesn’t respond to temperature change very quickly. Try this variation.

Why is mercury used in Fahrenheit instead of alcohol?

To avoid this unreliability, Dutch inventor Danie Fahrenheit replaced alcohol with mercury. Mercury has a higher coefficient of expansion than water, which means that changes in its volume with temperature are more noticeable. However, its value is almost six times less than that of alcohol.

Can you measure temperature with a water thermometer?

The best part about our Water Thermometer experiment is that you have all the materials you need in your own home. That’s right, you’ll be measuring temperature with this amazing homemade tool in no time. SICK Science® is a registered trademark of Steve Spangler, Inc. All Rights Reserved. Sick Science!