It’s possible sometimes to gather information from indirect evidence about an animal. The footprint of an animal may tell many things. A biologist named R. McNeill Alexander developed a formula to calculate the speed of a living animal from the trackways (series of footprints) that the animal left behind. His formula used the stride distance and hip height to calculate the speed.

            A TRACKWAY can be divided into three sections: The PACE, the distance between the right and left foot; the STRIDE, the distance between two successive steps (right-right, or left-left); and the GAUGE, which is the width of the tracks, telling how close the legs were together. Measure toe to toe.

Materials

• Scientific Calculator
• Meter Stick
• Timer
• Place to walk or run where foot prints show

 Procedures:

1. On sand (or other good footprint area) measure out 5 meters.

2. Walk or run across this area timing how long it takes to go the 5m.

3. Measure your foot length and multiply by 4 to get the hip height.

4. Measure your stride from the footprints.

5. Calculate your speeds (on data table below).

6. Compare the two methods of calculation

Formula for direct measurement:

speed = =                                                     __________meters/second

Formula for Indirect measurement: (Alexander's)  NOTE: g= 9.8 meters/second²

speed=                                             ___________meters/second