SUPERHUMANS & BIONICS:
Building Hi-Tech Exoskeletons
Can an ordinary person become a superhuman, or is that the stuff of fantasy and science fiction? Who wouldn't want to run faster, jump higher and lift objects many times heavier than their own weight? Technology has produced many machines that can do what humans cannot do, but can technology devise machines that will enhance the human body's natural strengths and abilities? Frontiers introduces you to scientists who have taken the first steps.
Activity: Making Strides
ACTIVITY: MAKING STRIDES
Before designing a machine that can perform better than the body does, it's necessary to understand how the body works. What we take for granted may be more complicated than we realize. Gait, or how a person moves, includes not only the up and down movement of limbs, but the posture of the body, how the weight is distributed, and how the limbs align with each other. It even includes the length of a stride. Stride length can tell us something about speed. When an animal moves slowly, its strides are short. As it quickens its pace, the length of the stride increases. Use this investigation to find out more about the relationship between speed and stride length.
- old socks
- pieces of different colored chalk
- mailing or duct tape
- metric measuring stick
- stop watch
Divide into cooperative groups of four and assign the following roles:
- Materials Manager: gathers materials and assigns cleanup duties
- Time Keeper: times the runners
- Chief Scientist: keeps group on track; assigns additional roles if necessary
- Marker Maker: powders chalk and attaches it to runner's shoe
- Place pieces of colored chalk into two old socks.
- Beat the socks against the ground until the chalk becomes powder.
- Use mailing or duct tape to secure each sock to the back of a sneaker. Tape it to the sneaker so that just the bottom of the sock makes contact with the ground. The rest of the sock should be taped up out of the way.
- Test the sock markers by taking several steps. The socks should leave a chalk mark at every step.
- Mark off a track on a playground about 10 meters (33 feet) long.
- Have a runner walk down the track at a normal walking speed.
- Record the time it takes. Measure three stride lengths. Then, record the average stride length.
- Have the runner walk quickly. Repeat step 3.
- Have the runner jog. Repeat step 3.
- Have the runner run fast. Repeat step 3.
- You may wish to use different colors of chalk for each type of movement. You can then identify and compare all of the tracks at once.
- You can replace chalk dust with baby powder.
- Make sure that only the tip of the sock contacts the ground. Otherwise, you may trip over the sock.
- How does stride length compare to speed?
- Why were three stride measurements taken?
- What can stride length tell us about the biology of dinosaurs?
- The faster the speed, the greater the stride length.
- An average is a more accurate representation.
- Long stride lengths indicate that these animals moved quickly. Some paleontologists believe that if the dinosaurs were active, they may have also been warm-blooded like today's quick-moving animals.
NOTE: Other concepts to discuss in connection with this segment include stored energy, springs, force, exoskeletons. This activity can be used with the segment on electrical stimulation of muscles, also in this program. You may wish to graph results of the investigation.
Scientific American Frontiers
Fall 1990 to Spring 2000
Sponsored by GTE Corporation,
now a part of Verizon Communications Inc.