Do lost people really walk in circles? One inquisitive teen finds out.

Last summer, 16-year-old Andrea Axtell read a riveting article in the papers: A family had wandered aimlessly in an Arizona desert after their car broke down. Family members said they felt as if they'd wandered in circles for hours before help arrived. That detail ignited Andrea's interest. "Without a compass or specific landmarks, do people who get lost end up walking in circles?" she wondered. "And if they do, why?"

These simple questions fueled Andrea's 10th-grade science project. Hungry for answers, she hit the library to conduct background research. Among many facts, she discovered that several body organs control direction and movement. For example:

* Eyes allow people to see their route.

* Structures in the middle ear affect a person's sense of balance.

* The brain controls whether a person's right side or left side is dominant, or exerts more control. "Studies of runners' strides show that the dominant foot pushes off with a greater thrust, which pushes the runner slightly right or left," she explains.

Armed with this information, Andrea designed an experiment to test whether people who don't know where they're going end up walking in circles. And several months later, that experiment nabbed a prize at the Intel International Science and Engineering Fair!

MAKE A PLAN

Like every well-designed science experiment, Andrea's follows a step-by-step plan. It begins with an educated guess, or hypothesis, about what the results of the experiment will be.

ANDREA'S HYPOTHESIS

Based on extensive homework, Andrea made an educated guess about what would happen in her experiment:

If a person can see the final destination, he or she will walk in a straight line to the destination. But if someone doesn't have a defined path to follow and can't see a final destination, the person will curve toward his or her dominant side. If allowed to continue, the person will eventually walk in a circular or elliptical path. The arc of this curved path will be influenced by the person's height or stride length.

To test her hypotheis, Andrea needed a plan of action, or procedure. Here's a first draft:

INITIAL PROCEDURE

1 Have test subject stand at one end of en empty football field.

2 Observe blindfolded test subject as he or she tries to walk straight across the field to the opposite side.

3 Stop test subject as soon as he or she crosses a sideline or reaches the opposite side.

What's wrong with this procedure? It's too vague. A well-designed experiment should include detailed instructions anyone can follow. This checklist will help you cover all the bases:

CHECKLIST

[check] What materials do you need? Make a list. Include amounts and measurements.

[check] Choose a control, or standard, to compare against your test variables. For a control, "I had one male and one female--not blindfolded--walk across the same field," Andrea says. "Both were able to walk in a perfectly straight line to the opposite goalpost."

[check] Determine your independent variables (the characteristics you change on purpose). Based on her research, Andrea chose three independent variables: the test subjects' gender, height, and dominant hand.

[check] Identify dependent variables (the characteristics that respond when you change the independent variables). In Andrea's experiment, the direction subjects curved would depend on their dominant hand. The curve's sharpness would depend on subjects' height.

[check] Keep all other variables constant. Andrea's test subjects were male and female teens. And she ran her trials at a single location.

[check] Repeat the experiment. Andrea conducted 32 trials: 16 boys and 16 girls.

This checklist helped Andrea write a clear and easy-to-follow final plan.

FINAL PROCEDURE

Last winter, Andrea conducted her experiment over a single weekend at a high school football field. Here's the procedure she followed:

You Need

* 17 teen boys, 17 teen girls, chosen at random

* football field with yard lines

* flags to mark the walk paths

* heavy blindfold, such as a dark polar-fleece scarf and hat

* tape measure

* 34 scale drawings of the football field on graph paper with room to record date about each test subject (see sample, above)

* pen or pencil to record your observations

Note:

Don't allow subjects to watch each other wlak the field. Test one person at a time while all other participants wait out of view of test site.

To Do

1 Place a mark at the center of each goal line. One at a time, have a male and female control subject walk from the center of one goal line to the mark at the center of the opposite goal. Record their names, heights, dominant hands, and paths on separate sheets of graph paper.

2 On graph paper, record a test subject's name, gender, and dominant hand. Use tape measure to determine subject's height, and jot it down.

3 Position the subject squarely at the center of the goal line on one end of the field. Blindfold the subject, making sure the person can't see anything.

4 Ask the subject to walk a straight line until told to stop.

5 Quietly follow the subject, placing a marker in the ground at the point where subject crosses each 5-yard line.

6 When the subject crosses a sideline or reaches the goal, stop the trial and unblindfold subject.

7 Use tape measure to record the distance between each marker and the starting point. Plot subject's path on graph paper.

8 Repeat steps 2 to 7 for all remaining test subjects.

Draw a Conclusion

How does being blindfolded affect a person's ability to walk straight? What factors seem to affect the direction a blindfolded person takes?

A WINNING PROJECT

Andrea's project led her to an intriguing conclusion: People who are lost and can't see a defined path or final destination do in fact tend to walk in circles. But Andrea never expected to walk off with a prize at the 2003 Intel International Science and Engineering Fair. "I just hoped my project would do well in our school fair," she says.

It just goes to show, says Andrea: "A winning project doesn't have to be save-the-world science. Just pick something that fascinates you."