# Heat Engines and the Second Law of Thermodynamics Part of the Series: Physics 2 Tutor (Thermodynamics, Oscillations & Waves)

## Related videos

The Second Law of Thermodynamics
Trace the history of the second law of thermodynamics, considered by many physicists to be the one law of physics most likely to survive unaltered for the next thousand years. The second law says that entropy--the degree of disorder in a closed system--only increases or stays the same.
Entropy: The Second Law of Thermodynamics
Turn to an idea that has been compared to a work of Shakespeare: the second law of thermodynamics. According to the second law, entropy, a measure of disorder, always increases in a closed system. Order can only increase at the cost of even greater entropy elsewhere in the system.
Consequences of the Second Law
The second law puts limits on the efficiency of heat engines and shows that humankind's energy use could be better planned. Learn why it makes sense to exploit low-entropy, high-quality energy for uses such as transportation, motors, and electronics, while using high-entropy random thermal energy for heating.
The First Law of Thermodynamics
This program covers the important topic of the first law of thermodynamics in Physics. We begin by discussing how this law is derived and how it is applied to practical problems in physics. The entire lesson is taught by working example problems beginning with the easier ones and gradually progressing…
Heat and Temperature
Beginning a new section, learn that heat is a flow of energy driven by a temperature difference. Temperature can be measured with various techniques but is most usefully quantified on the Kelvin scale. Investigate heat capacity and specific heat, and solve problems in heating a house and cooling a nuclear…
Heat Transfer
Analyze heat flow, which involves three important heat-transfer mechanisms: conduction, which results from direct molecular contact; convection, involving the bulk motion of a fluid; and radiation, which transfers energy by electromagnetic waves. Study examples of heat flow in buildings and in the sun's interior.
Matter and Heat
Heat flow into a substance usually raises its temperature. But it can have other effects, including thermal expansion and changes between solid, liquid, and gaseous forms: collectively called phase changes. Investigate these phenomena, starting with an experiment in which Professor Wolfson pours liquid nitrogen onto a balloon filled with air.
Heat and Work
The first law of thermodynamics relates the internal energy of a system to the exchange of heat and mechanical work. Focus on isothermal (constant temperature) and adiabatic (no heat flow) processes, and see how they apply to diesel engines and the atmosphere.
Reversibility and the Laws of Physics
Isaac Newton's laws of physics are fully reversible; particles can move forward or backward in time without any inconsistency. But this is not our experience in the world, where the arrow of time is fundamentally connected to irreversible processes and the increase in entropy.
Using Newton's Laws: 1-D motion
Investigate Newton's second law, which relates force, mass, and acceleration. Focus on gravity, which results in a force, called weight, that's proportional to an object's mass. Then take a ride in an elevator to see how your measured weight changes due to acceleration during ascent and descent.
Newton's Laws in 2 and 3 Dimensions
Consider Newton's laws in cases of two and three dimensions. For example, how fast does a rollercoaster have to travel at the top of a loop to keep passengers from falling out? Is there a force pushing passengers up as the coaster reaches the top of its arc? The answer…