Why do we measure heat in temperature

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What does the term "temperature" actually mean? Using examples from nature and technology, it is clarified what is actually meant by cold or warm and how one can measure temperature precisely and without feeling.

By: Rupert Ernhofer, a film by Wolfgang Voelker

Status: 07.09.2012

Essential for survival: the human sensation of warmth

A student dips one hand in warm water and the other in ice-cold water. Then he lowers both hands in lukewarm water - and each hand reports a different temperature! The human sensation of warmth is therefore not particularly suitable for measuring temperatures.

Our senses cannot measure temperatures, but they can show temperature differences. On a school trip to the far north, you have to wear suitable clothing to protect yourself from the low temperatures. But the worker at the blast furnace who drains red-hot molten pig iron also needs protective clothing. In everyday life we ​​use heat to prepare food, but in the refrigerator we extract heat from food so that it can be kept longer. Water can change its physical state depending on the supply or release of heat.

In the 19th century, English engineers succeeded in converting heat into mechanical energy. This made it possible to develop and build machines such as the steam engine or steam locomotive. When the blacksmith heats the iron, he can shape it and create the desired item. Targeted hammer blows on an object also add heat to the body.

The degree hike begins ...

The particle model can be used to explain what happens in bodies at high or low temperatures. It is also possible to display the individual aggregate states.

Colored alcohol is filled in a glass flask with a glass tube fastened by a stopper. The glass flask is held in ice water and then in boiling water until the water column no longer falls or rises. These two measuring points are marked and as Ice point and as boiling point of the water. The distance between these two points is divided into 100 equal sections. The Swedish physicist Celsius carried out this procedure. Nowadays a wide variety of temperature measuring devices are manufactured. In addition to the digital thermometers used today, liquid measuring devices are the most frequently used measuring devices.

The temperature scale cannot be arbitrarily extended in the minus range, since the absolute zero point is at -273 ° C. The English physicist Lord Kelvin discovered this. Lower temperatures are not possible because there is no more heat movement. The absolute zero point has a temperature of 0 ° K (Kelvin). Finally, our cartoon character Tobi Tüftler has problems converting the degrees of Fahrenheit that are common in English-speaking countries into degrees of Celsius.