Replies

Zeroth law of thermodynamics aka the law of zero entropy. The zeroth law was the last one defined and was an obvious afterthought, has to do with reaching a theoretical absolute zero ~ never to be attained ~ and thus in the same realm as the Heisenberg uncertainty principle. Yet there's not any one website that defines it completely and correctly. per wiki... The zero point of any thermodynamic temperature scale, such as Kelvin or Rankine, is set at absolute zero. By international agreement, absolute zero is defined as 0K on the Kelvin scale and as −273.15° on the Celsius scale. This equates to −459.67° on the Fahrenheit scale and 0 R on the Rankine scale. Scientists have achieved temperatures very close to absolute zero, where matter exhibits quantum effects such as superconductivity and superfluidity. per innovateus.net... Thermodynamics can be broken down into 4 laws. They are as follows. Zeroth law of Thermodynamics: Even though the zeroth law is added to the laws of thermodynamics after the 3 laws, it is usually discussed first. The law states, “Two systems each in thermal equilibrium with a third system are in thermal equilibrium to each other”. In other words, if 2 systems are in the same temperature as in the third system, then all 3 are in the same temperatures. First law of thermodynamics: The law states, “The change in the energy of a system is the amount of energy added to the system minus the energy spent doing work”. It means the total energy of a system remains a constant, even if it is converted from one form to another. For instance, the kinetic energy which is the energy that an object possesses when it moves is converted to heat energy when a driver presses the brakes on the car to slow down. There are often many phrases that are catchy to help people remember this law like, “Work is heat, and heat is work”. Basically, work and heat are equal. Second law of thermodynamics: This law states, “It is impossible for a process to have as its sole result the transfer of heat from a cooler body to a hotter one”. It is one of the most basic laws in science. If we put this in simple words, it says that heat could not flow to a system at a higher temperature from a system at a lower temperature by its own violation. For such an action, work must be done. If an ice cube is place in a cup of warm water, the ice cube melts as the heat from the water flows into it. The end result would be a cup of water that is slightly cooler. Ice cubes can only form if energy is used. Third law of thermodynamics: This law states that, “It is impossible to reduce any system to absolute zero in a finite series of operations”. This means that a perfectly efficient heat engine cannot be created. The change in entropy (measure of disorder) of a system when it converts from one form to another gets close to 0 as its temperature nears 0 on the Kelvin scale. Zero on the Kelvin scale is absolute lower limit to temperature - when atoms and molecules have the least possible energy. Entropy is defined as the availability of a system’s energy to do work. So, it follows that there is an absolute scale of entropy. As a result, no real system can ever reach 0 degrees on the Kelvin scale.