He thermometer Is an instrument used to measure temperatures. Depending on the type of thermometer, you can measure body temperature, water, air and many other things.
The thermometer is used in clinical, chemical and even gardening. Air and water expand and contract because of the temperature that exists.
When Galileo Understood the relationship between these two elements, it was the moment when he decided to create something that would help him to decipher the temperature, being in 1592 when he invented a rudimentary thermometer that would lay the foundation for the creation of more advanced thermometers.
This first thermometer did not have a scale, only used water to show changes in temperature and how it rose or fell.
It was the physicist Santorio who set a scale on a thermometer for the first time. But by not knowing properly how the water expands, these thermometers were very imprecise.
In the year 1714, the physicist and engineer Gabriel Fahrenheit Created the first thermometer that used mercury instead of water, as it expanded and contracted more quickly.
In addition, the mercury expansion is more predictable so it can be measured more easily, at the same time published its scale that today is called the Fahrenheit scale to measure temperature.
This scale was very famous in the century, but it would be the Swedish Anders Celsius who in 1742, and although initially rejected, would introduce the scale of more use today. This set 0 ° C as the freezing point of water and 100 ° C as the boiling point.
Thermometer parts
There are different types of thermometers that are used in different industries, each adapted to the place where they will be placed, but all have the same function: to measure the temperature.
We can highlight the thermometer known as clinical, which continues to operate on a mercury basis despite the many technological alternatives that exist in the market.
The reason why this is one of the most famous is because mercury goes from being solidified to liquid quickly, therefore it expands more quickly and offers a much more precise measurement.
Bulb
The bulb is the basis of mercury thermometers. It is at the bottom and is cylindrical or spherical depending on the artifact. The functionality of the bulb is to store the mercury and is usually made of stainless steel, but can be made of glass as well.
When it comes in contact with the place to measure and the temperature rises, the mercury leaves the bulb and when the temperature descends the mercury low and returns to deposit inside the bulb.
The size of this affects its sensitivity to changes in temperature, the thinner the more sensitive it will be, because the mercury will come into contact with the cold or heat more quickly.
Capillary
The capillary or stem is the tube through which the mercury flows. It is inside the glass body of the thermometer and is connected to the bulb.
It is the route that allows the mercury to travel until reaching the temperature at which the target is in measurement and back to the bulb.
The size of the stem also affects the measurement, because of being long mercury would take longer to fully expand, giving a broader range of temperature.
Body
The body is the glass tube that covers the stem. It is of elongated and triangular shape but the edges are softened, giving them a rounded appearance for a better handling. Usually measures 20 to 30 cm.
It is for this part that has given so many negative replicas to the mercury thermometers, since if it is ingested in considerable quantities can be toxic.
Because the body of glass is considered delicate and very fragile, it is imperative to take care of extremely strong drops or grips, because it could rupture and leak the liquid.
However, the glass is used because it filters the temperature well. One side of this is a magnifying glass, which makes reading easier.
Expansion compartment
The expansion compartment is the space above the stem, where gas and air are deposited while the mercury rises and the place where the mercury will be located in case it is exceeded.
When the mercury reaches the compartment, it means that the thermometer can not expand further and reach higher degrees of temperature.
Scale
The scale includes the marks on the body of the thermometer and indicates the temperature level. Depending on the thermometer you can have ° F or ° C.
Valve
The shrinkage valve is the connector between the bulb and the shank. Because it is narrower than the stem, this valve causes the mercury to slow down; Giving the person the necessary time to read the temperature reached.
Functions
Clinical thermometer
The use of the thermometer depends very much on the reason why it was manufactured. Each thermometer has been created specially to make its measurement in a certain place, but absolutely everyone has the same unique function: to measure the temperature of something. The 4 most important are:
- Clinical thermometer : Includes traditional thermometer and electronic. Its function is to take the temperature in humans (sometimes, animals). It is used in the mouth, armpit or rectum.
-Thermometer : Are used mostly in industry to measure the temperature of confined gases.
-Pyrometer : Type of thermometer whose function is to measure extreme temperatures, can reach temperatures higher than 600 ° C. It uses infrared technology and is used mostly in the metallurgical industries.
-Thermometer of resistance : Its function is to receive variations of electrical resistance and convert them into temperature variations.
References
- Radford, T (2003) A brief history of thermometers. Extracted from theguardian.com.
- Pearce, J (2002) A brief history of the clinical thermometer. Published in Quarterly Journal of Medicine, Volume 95, Issue number 4.
- British Broadcasting Corporation (2011) Types of thermometers. Excerpted from bbc.co.uk.
- (2016) Thermometer, use and functions. Extracted from instrumentsdelaboratorio.org.
- Markings, S. Different Parts of a Mercury Thermometer. Excerpted from oureverydaylife.com.
- Camilleri, P. Extracted from staff.um.edu.mt.
- Bellis, M. The history behind the thermometer. Excerpted from theinventors.org.