This is real weather balloon data from 1991, a weather balloon ascent in Coffeyville, Kansas, USA. Many more attributes (e.g.,, pressure, humidity, dewpoint, wind speed and direction) come in the data sets with Fathom, but this will get you started.

height is the altitude of the balloon in meters
time is the time since launch in seconds

First predict: how do you think height will depend on time?

Then graph it and see.

Make as simple a function as possible to fit the data and look at a residual plot.

How does the speed change over time? How can you tell from the residual plot?

Can you calculate instantaneous speed? (Sure. Use the prev( ) function!)

(found and downloaded by Tim Erickson, long ago)