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Thermodynamics

physical science Maturity 9-11 Vital Level 3 Next article →

Thermodynamics is a major branch of physics. It studies heat, work, and temperature. These concepts relate to energy, entropy, and the physical properties of matter and radiation.

system boundary
system boundary

Scientists use thermodynamics to understand how energy moves through the universe. It applies to many different fields. These include physical chemistry, biochemistry, and mechanical engineering. It even helps meteorologists understand the weather. This science helps us describe how systems respond to changes in their environment.

To study these changes, scientists define a thermodynamic system. A system is a specific collection of particles. These particles have average motions that define the system's properties. These properties are linked through equations of state. Everything outside the system is called the surroundings.

system boundary
system boundary

By studying the interactions between a system and its surroundings, we can predict how things behave. We can use these properties to find equilibrium. Equilibrium is a state where a system is stable. We can also use them to study spontaneous processes. These are changes that happen on their own.

Thermodynamics is governed by four fundamental laws. These laws act as an axiomatic basis for the science. The first law states that energy can be transferred between systems. This happens as heat, as work, or through the transfer of matter. The second law introduces a quantity called entropy. Entropy describes the direction a system can evolve. It also quantifies the state of order within a system. Scientists use entropy to calculate how much useful work can be extracted from a system.

Carnot engine (hot body - working body - cold body)
Carnot engine (hot body - working body - cold body)

There are different ways to look at these laws. Classical thermodynamics focuses on macroscopic properties. These are large-scale properties that we can measure directly. It describes systems that are near equilibrium. Statistical mechanics is a different approach. Also called statistical thermodynamics, it looks at the microscopic level. It studies the collective motion of individual particles. This field uses statistics and quantum theory to explain bulk properties. It shows how tiny atoms create the large-scale effects we see in classical thermodynamics.

Chemical thermodynamics is another important branch. It studies how energy relates to chemical reactions. It also looks at physical changes in the state of matter. The main goal is to determine the spontaneity of a transformation. This helps scientists know if a chemical reaction will occur naturally.

Kurzzeitfotografie sektkorken 06-19-s02 2017-09-03 01 hinnerk-ruemenapf exif
Kurzzeitfotografie sektkorken 06-19-s02 2017-09-03 01 hinnerk-ruemenapf exif

This branch grew from the study of mechanical heat engines. It eventually provided a massive amount of knowledge regarding chemical processes.

The history of this science is tied to the steam engine. In 1650, Otto von Guericke built the first vacuum pump. Later, Robert Boyle and Robert Hooke built an air pump in 1656. They discovered a link between pressure, temperature, and volume. This led to Boyle's Law. In 1712, Thomas Newcomen built an early engine. Later, James Watt improved efficiency by 100% using an external condenser.

Carnot engine (hot body - working body - cold body)
Carnot engine (hot body - working body - cold body)

Sadi Carnot is called the father of thermodynamics. In 1824, he published a work on heat and engine efficiency. This marked the start of thermodynamics as a modern science.

Many brilliant minds shaped the field. Lord Kelvin provided a concise definition in 1854. He linked heat to forces between bodies. Rudolf Clausius was another founding father. He published a paper in 1850 that stated the second law. In 1865, he named the concept of entropy.

Eight founding schools
Eight founding schools

Josiah Willard Gibbs launched chemical thermodynamics. In 1876, he published work on heterogeneous substances. He showed how to analyze chemical reactions using energy and entropy. His work allowed scientists to determine if processes would happen spontaneously.

Today, thermodynamics is essential for many technologies. It is used in aerospace engineering and materials science. It helps biomedical engineers and cell biologists. Even economists use these principles. The science is powerful enough to describe black holes in space. From tiny chemical reactions to massive engines, these laws rule the physical world.

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File:Eight founding schools.png
Eight founding schools.png
File:Carnot engine (hot body - working body - cold body).jpg
Carnot engine (hot body - working body -...
File:Kurzzeitfotografie sektkorken 06-19-s02 2017-09-03 01 hinnerk-ruemenapf exif.jpg
Kurzzeitfotografie sektkorken 06-19-s02...
File:system boundary.svg
system boundary.svg
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