A Mini-Lesson

LENGTHY RELATIONSHIPS

Foot Length, Stride, Leg Length, Height

Jennifer Johnson

EVOLUTION

 SYNOPSIS

 CONCEPTS & OBJECTIVES

Patterns can help understand the past, in light of the present.

Bipedalism has appeared several times.

OBJECTIVES: TO FIND THE RELATIONSHIP BETWEEN:

A. Foot Length and Leg Length B. Foot Length and Height C. Leg Length and Height D. Stride Length and Leg Length E. Stride Length and Speed

 MATERIALS

 STUDENT HANDOUTS

(see end of lesson for the formatted handouts).

 TEACHING STRATEGY

This lesson could be used as an extension of the "Footsteps in Time" lesson, or even a preliminary to that lesson. The use of this lesson, however, should NOT be considered as an alternative to "Footsteps...", as the intrinsic value of "Footsteps..." is that it uses real fossil tracks, of real hominins, and sheds light on the great antiquity of bipedalism in hominins (formerly "hominids").

See handouts (below) for introduction, procedures, and questions.

POSSIBLE EXTENSIONS or VARIATIONS:
There are many elements of science in crime scene investigations (CSI), or forensic science, and, as in thIs lesson, there are many ways to incorporate this exciting field in your Nature of Science efforts. A couple of lessons on our site which do this well are the Crime Scene Scenario and the Checks Lab. Try them. And an excellent online resource for all sorts of ideas and materials can be found on Eric Rude's site: "Sources of Forensic Information and Supplies."

NEW EXTENSION (5/06): Teacher Patti Carothers of Monte Vista High School in Danville, CA offers this extension: Cut 20-meter pieces of butcher paper for each lab group. Each group selects one person to step one foot into tempura paint and walk on the paper. After washing that color off (she uses purple for walking prints), they step into green paint with one foot and run on the paper. They are able to measure their strides that way. We dry a section of each one and hang them on the wall.

 ATTRIBUTION

Some of the ideas in this lesson may have been adapted from earlier, unacknowledged sources without our knowledge. If the reader believes this to be the case, please let us know, and appropriate corrections will be made. Thanks.

1. Original Source: Unknown

2. This lab was contributed by Jennifer Johnson at SENSI 96 in Hillsoborough, CA. She is now at the UC Berkeley Museum of Paleontology.

3. Edited / Revised for website by L. Flammer 4/99

INTRODUCTION

Look around at people's feet. You will notice that some people have longer feet than others. Do the individuals with longer feet also have longer legs? Are people with longer legs taller? Are the number of strides a person takes in a given distance different when he/she is running or walking? Does the person's stride length change with speed? Would the same hold true for birds? For dinosaurs? For early hominins? Can patterns of the present give you clues to patterns in the past?

Your job is to answer the following questions using the following lab procedures. You will gather data from classmates and family members to determine if there is a relationship between foot length, leg length, and height. You will also measure your stride while walking and running. Use the following terms when taking your measurements:

foot length: distance from heel to toe (without shoe)

leg length: distance from the base of the heel (calcaneous) to the hip joint (acetabulem)

hip Joint: top of femur on the outside of the hip joint (To find this spot, lift your knee until your thigh is parallel to the floor. Feel for the hip joint in your buttocks area, put your leg down, and measure from that point to the floor.)

height: distance from floor to the top of the head

stride length: usually the distance from the back of the heel of one footprint to the back of the heel of the next footprint of that same foot; in other words, the distance of TWO steps.

OBJECTIVES: TO FIND THE RELATIONSHIP BETWEEN:

A. Foot Length and Leg Length B. Foot Length and Height C. Leg Length and Height D. Stride Length and Leg Length E. Stride Length and Speed

MATERlALS

Meter Stick, Data Table, Overhead Transparencies, Graph Paper

PROCEDURES

Part A

1. In your lab group, gather the following data and Record in Data Table 1. foot length, leg length, height (all measurements must be in centimeters)

2. Calculate the ratio of leg length (L) to foot length (F) for each group member and record in Data Table 1.

3. Calculate the ratio of leg length (L) to foot length (F) for each lab member and enter your results in Data Table 1.

4. For homework, collect the above data from a minimum of three family members and/or friends.

5. Plot your data on the transparencies.

Part B

1. Measure and mark off a distance of 2,000 cm (20m) (D).

2. Walk the length while counting the number of strides (Nw). Record in Data Table 2.

3. Run the length while counting the number of strides (Nr). Record in Data Table 2.

4. Calculate the stride length (S) by dividing the distance (D) by the number of strides (N)

Sw = 2.000cm / Nw; Sr = 2.000cm / Nr

5. Measure and record your leg length.

6. Calculate the ratio of your stride length to leg length (S/L). Record in Data Table 2.

7. Graph (draw a graph using the data from as many people as possible, showing the relationship between stride length and leg length)

8. Repeat #6 and #7, but comparing stride with height (S/H)

CONCLUSION

1. Do you see a pattern on the graph? Explain.

2. Superimpose all (or several of) the group's graphs and determine if there are any relationships between the variables.

3. Determine if foot length can be used to predict height. Test you hypothesis by measuring a person's foot length and using your graphs to predict the height. Now, measure the height of that person. How close are you to the actual height? Calculate your percent error (difference between predicted and actual, divided by the actual, all times 100). Explain.

4. Pool the class data for the ratio of Leg Length to Foot Length. What is the average L/F ratio for people based on the class data?

5. Paleontologists use the ratio of stride length divided by leg length (S/L) to tell whether a dinosaur is walking, trotting, or running. Paleontologists use the following values to determine how a dinosaur might have been moving.

<2 walking 2 - 2.9 trotting >2.9 running

Examine the class data for the ratios of stride to leg length (Sw/L and Sr/L) to see if the values in the above chart would also apply to people.If not, what values would change?

ANALYSIS

1. If a person's footprints were discovered in someone's backyard, what information could be determined about the person who made the footprints? What information about the person could not be determined from the footprints?

2. If you had a dinosaur trackway, how could you use the processes we learned in this activity to draw some conclusions about the dinosaurs which made the tracks?

3. Why did you count your stride over a 2,000cm iength rather than make only one stride measurement?

4. Below is a series of footprints found in the mud outside school. Based upon the measurements given, calculate the leg length and heigth of the person. Who do you think the footprint belongs to? Write a paragraph describing what the person was doing.

Foot Length = 29 cm; Stride Length = 160 cm