- Steam Point : Highest of Water
- Ice point : Lowest of water
- We can measure anything with respect to these two temperature in our Celsius scale.
- Average : a huge number of particles, $10^{23}$.
- In mechanics, each molecule described by Newton's laws: $m \frac{d^2 \vec{x}}{dt^2} = \vec {F}$
- $3 \times 10^{23} \rightarrow$ average description.
![image](https://temp-public-img-folder.s3.ap-south-1.amazonaws.com/sathee.prutor.images/subject-images/iitpal/image/physics-class-11-unit-11-chapter-01-microscopic-and-macroscopic-approach-to-thermal-properties-l-1-4-qj6i2wgl9oe-6.jpg)