# What do you use scales for?

Sep 14, 2015

Physical scales are generally used to measure mass, but if you mean temperature scales, ""^oC and $K$ are commonly used in chemistry to express reaction conditions.

#### Explanation:

Typically laboratory scales and balances are used to measure mass in grams. In physics, there are spring scales that measure weight in Newtons.

In Chemistry, I often see the usage of ""^oC to express reaction conditions, like how biological reactions often occur at ${37}^{o} C$, or STP is at ${25}^{o} C$, or water freezes at ${0}^{o} C$.

I also often see $K$ used to do calculations, like using the ideal gas law, or using the universal gas constant $R$.

You may also see $K$ being used interchangeably with ""^oC when describing changes per unit of temperature (e.g. $\frac{J}{{g}^{o} C}$ vs. $\frac{J}{g \cdot K}$), since any $\Delta T$ is identical in $\text{^oC}$ as in $K$.