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Guide Index

Why Are Peppers Hot?

Can You Beat Jet Lag?

How Do Bees Fly?

Why Does Traffic Jam?

Sand to Nuts

Viewer Challenge

Transcript for Life's Little Questions

Related Scientific American Articles

Related Sites for Life's Little Questions
in the classroom
TEACHING GUIDES


Life's Little Questions:
How Do Bees Fly?


According to the laws of aerodynamics used by airplane engineers, bees and other insects should not be capable of flight. And yet many insect species have been flying for over 300 million years. So how do they do it? Frontiers travels to Cambridge, England, and the University of California at Berkeley in a quest to find out. One of the answers involves a vestigial pair of wings.

Curriculum Links
National Science Education Standards
Related Frontiers Shows and Activities
Activity 1: Build a Wind Tunnel
Activity 2: Testing Model Wings
Activity 3: Testing Plants




CURRICULUM LINKS


BIOLOGY/
LIFE SCIENCE


insects, plants

PHYSICAL
SCIENCE/PHYSICS


flight aerodynamics

TECHNOLOGY


engineering design, wind tunnels




NATIONAL SCIENCE EDUCATION STANDARDS

SCIENCE AS INQUIRY / PHYSICAL SCIENCE
5-8,
9-12:
Motions and Forces
HISTORY AND NATURE OF SCIENCE
5-8, 9-12: Science as a Human Endeavor
SCIENCE IN PERSONAL AND SOCIAL PERSPECTIVES
5-8: Science and Technology in Society
9-12: Science and Technology in Local, National and Global Challenges
LIFE SCIENCE
5-8: Structure and Function in Living Systems, Regulation and Behavior, Diversity and Adaptations of Organisms
9-12: Biological Evolution, Behavior of Organisms
EARTH AND SPACE SCIENCE
5-8: Structure of the Earth
9-12: Origin and Evolution of the Earth System




RELATED FRONTIERS SHOWS AND ACTIVITIES



ACTIVITY 1: BUILD A WIND TUNNEL

Insects defy all the rules of aerodynamics. Scientists have questioned how bees, flies, moths and other insects achieve sufficient lift to fly. How can such tiny wings lift relatively heavy bodies?

Scientists you meet on Frontiers build wind tunnels and utilize high and low technology as they explore the complexities of insect flight. Biologist Charles Ellington of Cambridge studies hawkmoths in his wind tunnel. Biologist Michael Dickinson at Berkeley uses a video-enhanced wind tunnel to find out how diminutive Drosophilas (fruit flies) can be so acrobatic.

Aircraft engineers use wind tunnels to test airplane design and efficiency. In this activity, you'll build a simple wind tunnel to help formulate and answer questions about how wind influences animals and plants.


MATERIALS
  • wind tunnel: 14" fan, boxes
  • model wings: pencil, cardboard, tape
  • various plants for testing
  • optional: video camera, large sheets of paper
PROCEDURE

  1. Set up your wind tunnel on a table or counter near a wall, as shown below. The table should be at least three feet long.

  2. Place a fan on one end of the table so that the wind is directed toward the other end. A circular or box fan at least 14" in diameter with three variable speeds works best. You may wish to use different sized cardboard boxes to vary the height of your wind source.

  3. Optional: On a large sheet of paper, at least 60cm high by 90cm long, draw a grid with 4cm squares. You may vary this grid based on the overall dimensions of your wind tunnel. The grid will allow you to measure changes in objects you place in your wind tunnel by using a video camera and image analysis.
EXTENSIONS

  1. The wind tunnel described here is a simple version. You'll find other plans for building wind tunnels and activities at these websites:
  2. The research on flies you see on Frontiers utilizes high-speed and stop-action photography. To see some great stop-action shots, as well as get tips on how to set up stop-action shots with a 35mm camera, visit: members.aol.com/mjbrown/HTML/hsp.html.



ACTIVITY 2: TESTING MODEL WINGS

Use the wind tunnel to explore why geese fly in formation.

PROCEDURE

  1. Make two or more model geese wings by attaching cardboard to a pencil with tape. (See drawing of model wing.)

  2. One student should hold one wing approximately 30cm away from the fan, to simulate the wing of the lead bird in a V formation of migrating geese.

  3. A second student should hold another wing behind the first wing. Hold the second wing so its flat surface is parallel with the plane of the table and is held stable.

  4. Turn the fan on the lowest speed. The first student should begin slowly flapping the lead wing up and down.

  5. As the first wing is moved up and down, observe the effect on the second wing.

  6. Repeat the experiment with different wind speeds.
QUESTIONS

  1. What effect did flapping the first wing have on the second wing at low wind speeds? Higher wind speeds?

  2. What advantage do you think a bird second in line might have? For example, do you think it might use less or more energy? Defend your answer with your observations from the wind tunnel.

  3. How can you improve this model of birds in flight to be more accurate?

  4. How might planes flying in formation be affected by the aircraft in front?


ACTIVITY 3: TESTING PLANTS

Use the wind tunnel to examine why certain plants do not break in strong winds.

PROCEDURE

  1. Obtain samples of different potted plants or trees. Plants should be small enough to place in your wind tunnel or sit at the end of the table so the leaves are placed in the path of the wind.

  2. Place a plant sample in your wind tunnel. Sketch the shape of the plant before the fan is turned on. (If you have a video camera, you may want to use it to record the experiment.)

  3. Turn the fan on its lowest setting. Record any changes in the shape of the entire plant. Also, write down any interesting observations you can see for individual stems or leaves. For example, do leaves stay rigid or turn in the wind?

  4. Increase the speed of the wind and record any changes you observe.
QUESTIONS

  1. How did the shape of the plant change as wind speed increased? Did the shape become more aerodynamic?

  2. How might the change of shape, or lack of change, help protect the plant during high winds?

  3. Based on your observations, do you think the plants you tested are adapted to habitats that experience high winds? Explain why or why not.

  4. What other adaptations might help plants to survive in areas with very strong winds?
EXTENSIONS

  1. Nonliving components of nature are also subject to the wind. Design an experiment to answer the question: How are sand dunes formed?

  2. Extend your sand dune experiment to ask: How do plants help stabilize sand dunes?





 

Scientific American Frontiers
Fall 1990 to Spring 2000
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