If you are interested in inventions, you will be impressed by Galileo's Thermometer. At a minimum, because this is the very first thermometer, which was invented by the same Galileo Galilei, the founder of classical mechanics. To those who invented the telescope and discovered other planets of ours solar system and in general he did an incredible amount of things for science.

But let's return to Galileo's thermometer. This is a glass flask filled with liquid. Small glass buoys filled with dark liquids of different densities float in the liquid. Each buoy has a gold temperature tag attached to it. It's simple - under the influence of cold, the liquid in the buoys expands, and the buoys themselves float. And since the density of liquids is different, they expand at different temperatures. Let's remember school course physicists? In fact, detailed instructions information on how to determine the temperature in a room is right on the wooden stand of the thermometer.

How does it work

So, as we already understood, liquids with different densities react differently to changes in temperature. The colder it is, the higher the buoys. Since the flask is narrow, they begin to “crowd” from above, and then the temperature is determined by the tag on the lower of the floating buoys. And if all the balls have sunk, on the contrary, they look at the top one.

Of course, now that we can detect the most subtle temperature fluctuations with ultra-sensitive instruments, this ancient device is perceived primarily as an elegant decoration for the room. But, what is important, the temperature in the room can really be determined from it - with a small error. By the way, at the very beginning of use it is important to allow the liquid in the flask to adjust to room temperature, so do not expect instantaneous accurate readings. Why wait? Aesthetics, of course!

The accuracy of temperature readings fluctuates around 0.4 degrees Celsius. The Galileo thermometer, which you can buy at the Mr. Geek store, shows temperatures from +18 to +26 degrees. But if you want to look into the future and predict changes in the weather outside, another ancient invention will help you - the Storm Glass Crystal Weather Predictor.

Characteristics

• glass flask with liquid and cones, in a wooden stand with instructions in Russian and English;
• temperature range: from +18 to +26⁰С;
• 5 cones with liquid of different densities: 18, 20, 22, 24 and 26⁰С;
• material: glass, wood;
• blown by hand;
• environmentally friendly liquid without freons;
• harmless to health;
• used indoors;
• size in stand (L*W*H): 8*7*26 cm;
• flask diameter: 3.5 cm;
• packaging: cardboard box;
• package size (L*W*H): 8*9*33 cm;
• weight: 480 g.

Thermometer?" is not so simple. This object, descriptions of which can be found in ancient writings, went through a serious evolution over a century and a half until it took on its current form.

History of the invention of the thermometer: stages

• 1st century AD. Description of the first thermometer by Heron of Alexandria.
• The turn of the XVI - XVII centuries. Thermoscopes created by Galileo and other scientists.
• 1724 - Gabriel Fahrenheit developed a temperature scale for a mercury thermometer.

Age of Galileo

According to indirect information, the inventor of the first thermometer was Galileo Galilei. The surviving works of the scientist contain references to this device. Between 1592 and 1597, Galileo invented the thermoscope, which was a glass containing water and air that showed changes in temperature.

This invention is mentioned in a letter to Galileo from the mathematician Giovanni Sagredo. The latter proposed improving the thermoscope by adding a scale for measuring temperature. Sagredo later wrote to Galileo how he used a thermoscope to measure the temperature of the air in different months of the year.

Another mention of Galileo's thermoscope can be found in a letter from a certain Father Castello to Monsignor Cesarini in 1638. The priest was telling the recipient how he had witnessed Galileo use a thermoscope during a lecture in 1603.

The Italian doctor Santorio, a professor at the University of Padua, used a thermoscope in his practice. With its help, he established normal human temperature and used Galileo's invention as aid when making a diagnosis.

Santorio is sometimes called the inventor of the thermometer, but the scientist never attributed this honor to himself in his writings. On the contrary, in his Commentary on Galen he calls the thermoscope the most ancient instrument.

In 1624, Jesuit Jean Levercon published a book in which he first used the word “thermometer.” He described it as a device for measuring heat and cold, which is located in the air. The book became popular and was translated into European languages.

The Jesuit named a certain Cornelius Drebbel as the inventor of the thermometer. He was a native of Holland who was fond of alchemy and claimed to have constructed a perpetual motion machine. Unable to convince the assembly of alchemists and learned men of Prague of his invention, Drebbel was thrown into prison by order of the emperor. One of his works actually contains a description of the operation of a thermometer, due to which Leverkon may have named him as the author of the discovery.

After Galileo

Scientists of the 17th and 18th centuries knew about the thermoscope and were looking for ways to improve it. The first known diagram of it was made by Giuseppe Biancani in
1617. In 1638, Robert Fludd depicted a thermometer in the form of a vertical pipe, closed on top by a flask of air. Its lower hole went into a vessel with water. The liquid level in the pipe depended on the expansion and compression of air.

The most serious modification of the thermometer in this era was made by Ferdinand II, the Grand Duke of Tuscany from the Medici dynasty, famous for his patronage of science. He himself did not shy away from scientific pursuits. The Medici took an ordinary thermometer, filled it to a certain limit with alcohol, and then sealed it with molten glass. The new thermometer did not depend on atmospheric pressure.

Fahrenheit

Gabriel Fahrenheit was born in 1686 in Danzig into a merchant family. Having lost his parents at an early age, he left commerce for science and travel. While studying meteorology, Fahrenheit improved the thermometer and over the course of many years developed a scale for measuring temperature.

He began experiments in 1706, first using alcohol in his experiments, but then decided that mercury would give more accurate readings. In 1724, Fahrenheit completed the liquid thermometer. He was able to achieve relative accuracy of readings by establishing several points whose temperature was known and dividing the distance that was between them.

In the 1730s and 1740s, scales developed by Delisle and Reaumur were also used in thermometers. In 1742, the Swede Andreas Celsius developed a new scale for measuring temperature, which gained great popularity.

When answering the question "Who invented the thermometer?" it is worth recognizing the primacy. The rest of the scientists refined his model and created the thermometer we are familiar with.

Galileo Galilei - Italian physicist, mathematician, astronomer and philosopher who made invaluable contributions to scientific revolution 16th century. He was the first person to discover that the density of a liquid changes as a result of increasing or decreasing temperature.

The thermometer, named after this scientist, is made of a closed glass cylinder. Inside it is a clear liquid and several cones. Each cone has a certain weight. They rise or fall as the temperature changes. Besides everything else, Galileo thermometers are beautiful in appearance :) Perhaps these are the most beautiful thermometers of all.

Although Galileo did not actually invent this thermometer, it was named after him because without his discoveries the invention would not have been made. Such thermometers have been produced since the end of the 17th century.

Each of the cones floating inside the vessel has a weight indicated on it. Each one is also engraved with the number and degree. Their weight is regulated by a counterweight. The weight of each cone varies slightly. Colored water in the bubbles is added so that each has the same density - this also makes the thermometer even more attractive.

The lowest cone shows the correct temperature. When the density of the liquid inside the cone changes, gravitational force exceeds the buoyancy force, causing the cone to sink.

Modern thermometers seem to be something familiar and ordinary. And few people think that until relatively recently, the temperature of surrounding objects, water and air had to be determined only by sensations. A person could only tell whether it was warm or cold today, but there was nothing to accurately determine the temperature.

The Middle Ages became an era, and interest in science and precise measurements increased. Mathematics, with its methods of quantitative assessment of phenomena, has firmly occupied the position of “queen of sciences”. People have learned to quite accurately measure the volume and weight of the most various items. And only temperature could not be measured for a long time. And this is not surprising, because it is impossible to see or objectively evaluate this characteristic of material objects in the usual way.

Galileo thermoscope

Luck at the very end of the 16th century smiled on one of the greatest minds of his time, the Italian Galileo Galilei. He is widely known for his discoveries in astronomy, and for having developed and implemented a number of very useful instruments. Galileo is also considered one of the creators of modern mechanics.

In the scientist’s manuscripts, researchers found images of a device called a thermoscope, as well as a description of experiments carried out using this instrument, unusual at that time.

Galileo's prototype of a modern thermometer was a ball made of glass, to which a glass tube was soldered. Conducting his experiments, Galileo warmed a glass ball, and then turned it over, immersing the free end of the tube in a container with tinted liquid.

As the ball gradually cooled, the volume of air in it became smaller. The place of air was taken by the air, which rose through a glass tube. In Galileo's thermoscope, the working agent was not mercury, but water. This design of the thermometer made it possible to judge how hot a particular body was compared to the object.

But the accuracy of the measurements was quite low at that time, since Galileo’s instrument depended on atmospheric pressure.

Half a century later, other researchers and inventors significantly improved the first thermoscope by adding a scale to the device. If it was possible to tell an object whether it was colder or hotter than another object, it was now possible to find out the extent of the differences in temperature. Of course, temperature instruments were very imperfect and very different from those convenient and accurate devices that humanity widely uses today.

Video on the topic

In the history of the creation of thermometers, it is impossible to establish either an exact date or just the name of the inventor for the reason that many scientists and naturalists of the end of the sixteenth century worked simultaneously on the problem of measuring temperature. They offered various instruments for measuring the temperature of air, the human body, water, metal, etc. The most famous are Galileo Galilei and the doctor Santorio Sanctorius.

Who worked on the creation of the thermometer

Galileo Galilei developed and described the idea of ​​the thermoscope between 1592 and 1597. This fact was witnessed by his disciples. The operation of the thermoscope was based on the ability of air to expand when heated, and it consisted of glass and a tube. The device could measure temperature changes; there was no scale. Later, in 1657, Galileo's students used beads on a tube to record changes in temperature.

Santorio Sanctorius of the University of Padua in 1626, a device for human body temperature. It was a ball and a graduated tube filled with a colored liquid. The device was so bulky that it was installed outside the building.

It is believed that the Dutch inventor, optician and metrologist Cornelius Drebbel, Lord Francis Bacon, philosopher, founder of empiricism, Robert Fludd, British doctor and mystic philosopher, French hydraulic engineer and architect Salomon de Causse were involved in the development of thermometers.

Descriptions of liquid thermometers date back to 1667. And the physicist Evangelista Torricelli from Florence converted an air thermoscope into an alcohol thermoscope. The bulky vessel with water was removed, the tube ended up at the bottom, and the device stopped changing due to changes in atmospheric pressure, as was the case with the air thermoscope. The thermometer used wine alcohol because the water froze.

In 1703, the Frenchman Amonton improved the air thermometer. The principle was based on changing the elasticity of air. The model was imperfect, but a cold level was introduced at which elasticity was lost, later called “absolute zero.”

The appearance of a scale on thermometers

It took a long time to select the starting points for uniform division of the scale of thermometers of various designs. One of the first options was proposed in 1694 by the Italian physicist Carlo Renaldini. He took it for extreme points The thermometer shows the melting point of ice and the boiling point of water. Two decades later, in 1714, Gabriel Fahrenheit chose several base points. The temperature of a mixture of snow and ammonia or salt was proposed as zero. Point 32 showed the freezing of pure water, 96 gave the body temperature of a healthy person, and the boiling point of water was 212. In addition, Fahrenheit proposed a mercury thermometer.

The French physicist Rene Reaumur proposed an alcohol scale from 0 to 80 in 1730. Mikhail Lomonosov proposed a scale divided between the freezing and boiling of water into 150 divisions. But the most popular was the scale proposed in 1742 by Anders Celsius. The boundary points of the Celsius scale are the freezing point of water and its boiling point. The scale itself was divided into 100 intervals. Initially, the boiling point was taken to be 0, and the freezing point to be 100°C. The scale was “inverted” a little later, presumably after the death of Celsius, by his contemporaries, the botanist Carl Linnaeus and Morten Stremer, the astronomer.

Only in 1848, Lord Kelvin, physicist William Thomson calculated and proved the existence of absolute zero at a temperature of -273.15 ° C. By this time, the design of thermometers had changed so much that it became possible to produce them on an industrial scale and sell them for the needs of laboratories and industries. Into medicine a century later, in the middle of the 19th century.

Galileo thermometer

Galileo thermometer

Galileo thermometer It is a sealed glass cylinder filled with liquid in which glass spherical buoy vessels float. Each such spherical float has a gold or silver tag attached to the bottom with the temperature value stamped on it. Depending on the size of the thermometer, the number of floats inside varies from 3 to 11. Currently, the thermometer has aesthetic value as a spectacular piece of furniture.

History of invention

Galileo's thermometer close up

The name comes from the Italian physicist Galileo Galilei, who in 1592 invented the thermoscope, which became the progenitor of all thermometers. According to some sources, Galileo himself had a very indirect relationship with the creation of this device, which is often used as a souvenir; according to other sources, the world owes this invention of the late 16th century to Galileo.

Operating principle

The floats are filled with liquid in different ways in such a way that their average density is different: the smallest density is at the top, the highest at the bottom, but for all of them it is close to the density of water, differing from it only slightly. As the air temperature in the room decreases, the temperature of the water in the vessel decreases accordingly, the water contracts, and its density becomes greater. It is known that bodies whose density less density the liquid surrounding them float up in it. As the temperature in the room decreases, the density of the liquid in the cylinder increases and the balls rise up one after another, and as the temperature rises, they drop. This effect is achieved due to the very high precision of thermometer manufacturing. All balls are calibrated by ascent temperature in the range of 0.4 °C. The temperature range measured by the thermometer is around room temperature: 16-28°, step: 1 °C. The current temperature value is determined by the lower of the floating balls.

see also

Notes

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