Question

Describe a process in which entropy appears to decrease, but is coupled with an increase in entropy elsewhere in the universe. Do not use freezing liquid and please make the answer at least 150 words in length.

Answer 1

The second law of thermodynamics can also be stated in terms of entropy. Entropy is a measure of disorder in a system. Entropy appears to decrease, but is coupled with an increase in entropy elsewhere in the universe. Since it takes work to increase the orderliness inside a closed system, an increase in order corresponds to a decrease of entropy. Hence, the second law of thermodynamics can also be expressed in terms of entropy, a decrease in the entropy of a system requires an input of work into that system.

Application of the second law of thermodynamics helps explain the various ways in which engines transform heat into mechanical work, as for instance in the gasoline engine of a car or in a steam turbine.Some part of the heat generated inside the engine is used to perform the work moving piston inside the engine cylinder. The piston is connected to the crankshaft via connecting rod. The reciprocating motion of the piston is converted into the rotary motion of the crankshaft, which is converted to the rotary motion of the wheels via gear box. The remaining part of the heat generated inside the engine is released to the atmosphere as the exhaust gases or tailpipe emissions. In this case the engine where heat is generated is called as source, whereas the atmosphere where heat is released is called as sink. As per the second law of thermodynamics, higher the temperature of the source and lower the temperature of the sink, higher is the efficiency of the engine.