The experiments in this lab show a person moving along, walking, biking, or something else. The speed of the person can be described as "fast" or "slow." This is a qualitative measurement because it depends on your judgment and not a specific number value of the speed. When you use a formula for speed, you can calculate the speed of the glider as a number from the data collected in an experiment. This makes it possible to compare accurately the speed in one experiment with the speed in another experiment. When a value is a number it is called quantitative.