Title: Dino Long Legs: The Relationship between Stride Length and Leg Length
Authors: Mike Baxter and Robert Lawrence, D. C. Everest Jr. High, Schofield WI. 54476, mbaxter@dce.k12.wi.us
Grade: Middle School Earth Science.
Suggested Time: Two 45 Minute periods.
Overview of lesson: In this activity the students will work with accepted relationships between leg length, stride length and speed to determine information about an individual that only left behind tracks.
Students Prior Knowledge: Students need to know the length of their leg from the hip to the base of the heel. Students will also need to know their height. The students will have to find out their stride length which can be found by measuring the distance from the back of the left heel of one footprint to the back of the left heel the next time it hits the ground.
Background Information: Students need to know that there is a direct relationship between the length of a person’s leg and the height of the person. Students will also need to know that there is a direct relationship between the length of the leg and the length of the stride of a walking individual. There is also a relationship between the length of the leg and the length of the stride of a running individual. Paleontologists use this information and tracks to calculate the height and speed of dinosaurs.
Materials: Tape measure, meter stick, graph paper and a 2000 cm long walkway marked off so the stride can be measured.
Student Activity Part A: Students will work in groups to collect their heights and lengths of their legs from their hip joint to their heel. The students will also collect the length of their walking stride and the length of the running stride. Later the student's data will be included in with the larger class set of data.
Student Activity Part B: Students will measure a group of tracks produced by a walking unknown individual and will be asked to extrapolate on their graphs how long the leg length of the individual is from the SL/LL graph and then extrapolate the individuals height from the graph of Height/Leg length graph.
Teacher Notes: Paleontologists use the ratio of stride length divided by leg length (SL/LL) to tell whether a dinosaur is walking, trotting, or running. Paleontologists use the following values to determine how a dinosaur might have been moving.
Less than 2 walking
2 to 2.9 trotting
Greater than 2.9 running
There is a suggested data table attached at the end of this lesson (or click here). Examine the class data for the ratio of stride length to leg length to see if the values would apply to people. The sample data for walking should show that children and adults have a Stride length to Leg length ratio of less than two. Running ratios should be greater than 2.9. The unknown tracks will be made using sheet rocker’s stilts rented from a construction rental store. The stilts take a bit of practice to walk on and can be adjusted for length. The direct relationship between height to leg length is a 2.0:1.
Vocabulary: stride length, stride, ratio
Interdisciplinary connections: Math: Use of measurements, division and graphing skills.
Extension Activities: Students can use the scale models of the dinosaurs and diagrams of dinosaurs available to calculate the leg length and therefore the stride length of a running or walking animal. Students can use the length of the leg of an animal, such as a dog, cat, or an ostrich and calculate the running stride and walking stride. If an animal is available it might be possible to make a walking track and measure the stride and see if there is a relationship between the leg length and stride length.
Wisconsin State Science Standards:
A.8.3 Defend explanations* and models* by collecting and organizing evidence* that supports them and critique explanations and models by collecting and organizing evidence that conflicts with them.
A.8.6 Use models* and explanations* to predict* actions and events in the natural world
B.8.3 Explain* how the general rules of science apply to the development and use of evidence* in science investigations, model*-making, and applications*
C.8.2 Identify* data and locate sources of information including their own records to answer the questions being investigated
C.8.5 Use accepted scientific knowledge, models*, and theories* to explain* their results and to raise further questions about their investigations*
F.8.2 Show* how organisms have adapted structures to match their functions*, providing means of encouraging individual and group survival within specific environments
Wisconsin State Math Standard:
D.8.1 Identify and describe attributes* in situations where they are not directly* or easily measurable (e.g., distance, area of an irregular figure, likelihood of occurrence)