Stepping Science: Estimating Somebody’s Height from Their Walk
Have you ever noticed you need to walk faster just to keep up with some people, or decrease your pace to walk with other people who are going slower? This is likely because of the difference in leg length between you and the person you are walking with. In this science activity, you’ll get to investigate just how much faster or slower different people walk, and see if you can use the relationship between a person’s walking pace and their height to estimate your own height.
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.
A pedometer is an instrument that is often used by joggers and walkers to tell them how far a distance they have gone. On some pedometers, when a person sets the instrument before an outing, they must enter their height into the pedometer to get an accurate reading.
Extra: Try this activity with a greater number of people. For example, you could go to a park with a jogging path or a similar location where you can ask for volunteers as they pass by. Try to collect data from at least 10 volunteers. Is there much variation in the ratio of step length to height when comparing many people? Does collecting more data make your height estimation more accurate?
Extra: You could do this activity again but this time have volunteers walk slowly, moderately fast or very fast. How does a person’s speed affect their step length?
Extra: The human body has many other interesting ratios, such as mentioned in the Background of this activity. You could look into other ratios in the human body and come up with an activity like this one to investigate them. See the More to Explore section on the next page for relevant resources. What other ratios are consistently found in the human body from person to person?
Observations and Results
When you divided your volunteers’ step length by their height, did you get a ratio value close to 0.4? Were you able to roughly estimate your height based on this, accurate to within two inches?
The measurements of a pedometer are based on the hypothesis that all people have common ratios and proportions, even if they are different heights. In this activity you should have found this hypothesis to be pretty accurate. On average, people have a step length of about 2.2 to 2.5 feet. In general, if you divide a person’s step length by their height, the ratio value you get is about 0.4 (with a range from about 0.41 to 0.45). This is why you can take a person’s step length and divide it by about 0.43 to roughly estimate their height – the estimated height will likely be within two inches of (and probably much closer to) their actual height.
More to Explore
Teisha Rowland, PhD, Science Buddies
Science Buddies |
Height, distance, walking, estimations
Explore Our Science Videos
Toy Sailboat with Keel
4 Easy Robot Science Projects for Kids
DIY Toy Sailboat