2nd and 3rd law

2nd and 3rd law

2nd law of Thermodynamics

When objects of different temperatures are brought into contact, the flow of themal energy is always from the higher-temperature object to the lower temperature object. Temperature in Kelvin

Discussion: Why is the 2nd law more restrictive than the first?

Entropy

• Measures the amount of disorder in a system.

• Related to the 2nd law

•  $\Delta S=\frac{Q}{T}$  

• Adding Heat increases entropy

• Removing heat decreases entropy

Discussion: Can Entropy decrease in the Universe?

No. Though entropy can decrease in a system more disorder will enter the universe or disorder will remain the same.

3rd law

• It is impossible to lower an objects temperature to absolute Zero

• Temperature in Kelvin

Research: Discuss and Describe the Carnot efficiency theorem.

Conclusions

• 1st law- you cant get something from nothing. More work can be done than heat energy inputed but you can break even

• 2nd law- more restrictive- cant break even some heat inputed will be lost

• 3rd law- nothing can be cooled to absolute zero. This is why we cannot have total energy efficiency