Why does thermometer use mercury

The alcohol would have cooled down too fast. Mercury also has a high coefficient of expansion, but it is not too high. This means you can subject the mercury in a thermometer to heat and it will react. You can then look at your thermometer, and you will have enough time to read the temperature it displays before the mercury goes back down again.

Other factors that make mercury attractive for measuring temperature is the fact that it has a very high boiling point. Alcohol has a much lower boiling point, and it would not even be able to measure the temperature of boiling water.

Although it can measure temperatures much lower than mercury can. In addition, mercury is the only metal that is a liquid at room temperature, making it an attractive candidate. It is also cheap to acquire and very accurate at measuring high temperatures. Lastly, you do not need an external power source like a battery or electricity to run a mercury thermometer. Mercury powers itself, making it an attractive substance. Although mercury thermometers pose many benefits to users, they also have their drawbacks.

Temperatures can be checked in the mouth, rectum, armpit, ear, and across the forehead. While rectal temperature is the most accurate it is often impractical to measure temperature this way. There are many types of thermometers. The oldest thermometers used are mercury in glass.

Newer thermometers include non-mercury liquids in glass and digital and electronic devices that use sensors to measure temperature. Thermometers that check body temperature in the ear, across the forehead, or have a digital display do not contain mercury.

The Environmental Protection Agency EPA recommends using mercury-free thermometers but it does not recommend any specific brand. You should pick a thermometer that is easy to use and read. Potentially harmful effects from broken thermometers vary depending on the type of thermometer. The most concerning are mercury-containing thermometers. However, many of the electronic thermometers contain button cell batteries which can be very harmful if swallowed.

If a battery is swallowed, contact the battery ingestion hotline at Exposure to broken glass thermometers can lead to injury from the broken glass. Studies of children in emergency rooms have noted injury to the mouth, rectum, and ear from broken thermometer glass.

There can be other dangers related to glass thermometers depending on the type of liquid inside them. If you have a liquid-in-glass thermometer, it is important to be able to tell if it contains mercury.

A few simple steps can help. If the liquid is not silver in color, it does not contain mercury. The non-silver liquid-in-glass thermometers typically contain a colored alcohol. Contact with the skin or inside the mouth could cause minor irritation or a burning sensation that should go away quickly. If the liquid spills, rinse off exposed areas with water.

If the liquid gets in the eye, flush the eye with water for 15 to 20 minutes, then call Poison Control. Galinstan liquid consists of tin, indium, and gallium. According to its manufacturer, Galinstan is not toxic when swallowed because it passes through the digestive system without effect. Inhalation is also not a concern because there is no absorption through the lungs. Skin exposures to Galinstan can cause irritation. If the liquid is silver in color it might be mercury.

Spilled mercury has a unique appearance. It is a thick, shiny, fast-moving liquid metal that can break up into little balls that reform when pushed together. But not all thermometers with silver liquid contain mercury. Mercury can be poisonous in certain situations. Most oral and rectal thermometers contain about 0. The main health problems from mercury are from the vapors. These are produced at room temperature and especially when mercury is heated. EPA has launched an effort to reduce the use of mercury-filled non-fever thermometers used in industrial settings where suitable alternatives exist.

To date, multiple ASTM standards have been updated to approve the use of mercury-free alternatives for temperature measurement. View a list of the updated ASTM standards. This is to help remove the threat of thermometer breakage and the subsequent release of mercury vapor indoors.

The Health Care Without Harm website presents information on specific state laws, resolutions and declarations. A variety of accurate and reliable mercury-free fever thermometers are available at your local pharmacy. The most similar alternatives to mercury fever thermometers are battery- and solar-powered digital thermometers.

These are similar to mercury thermometers in both price and use. These can all be used orally, rectally, or in the armpit. You should choose a thermometer that is easy to use and read.

If you are choosing a battery-powered digital thermometer, choose one that contains a replaceable battery. Some of these thermometers do not have replaceable batteries.