  ### Home > PC3 > Chapter 7 > Lesson 7.2.1 > Problem7-72

7-72.

The dew point is the temperature at which the air would be completely saturated with water ($100\%$ humidity). How can $Δ$ be used to represent the change in dew point with respect to the change in height? Using the data from the balloon problem, calculate the average rate of change of the dew point with respect to height from $t=0$ to $t=3600$. Homework Help ✎

$\left. \begin{array} { | c | c | c | c | } \hline \text { Time (s) } & { \text { Altitude } ( ft ) } & { \text { Pressure } ( mb ) } & { \text { Temp } ^ { \circ } C } & { \text { Dew Pt } ^ { \circ } C } \\ \hline 0 & { \text { ground level } } & { 1000 } & { 17.8 } & { 9 } \\ \hline 360 & { 2900 } & { 925 } & { 25.6 } & { 4 } \\ \hline 650 & { 9900 } & { 850 } & { 13.0 } & { - 13 } \\ \hline 2750 & { 19900 } & { 500 } & { - 4.1 } & { - 26 } \\ \hline 3600 & { 24900 } & { 400 } & { - 179 } & { - 37 } \\ \hline \end{array} \right.$

$\frac{\Delta\text{ dewpoint}}{\Delta\text{ height}} = \frac{-37 - 9}{24900 - 0}$