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This week's LabZone activity
Dec. 13, 2006
Whirl-y-bird vs. Whale-y-bird
What do whale fins, shark skin, mackerel tails, and golf balls all have in common? Explore the science of hydrodynamics and biomimicry with this fun experiment.
Objective
In this experiment you will test if using biomimicry can improve the design of a very simple aircraft, the whirlybird.
Introduction
Humpback whales are close cousins of the blue whale, the largest known animal on earth! They are members of the baleen whales and are famous for their "singing" ability. Another talent of the humpback whale is that it hunts for food by circling beneath a school of fish and creating a "bubble net" from below. The "bubble net" will surround the schooling fish so that the whale can swim up from below, mouth open wide to eat them all. To make the bubble net, the huge animal must turn a very fast, tight circle while swimming in the water. How does such a large animal maneuver so well through the water?
Humpback whales have a very stiff body, similar to a large submarine. To help overcome this problem they have very long flippers on either side of their body that they use to maneuver. The front sides of the flippers have an irregular, scalloped edge that had puzzled scientists until they realized the secret. The bumps of a humpback whale's fins are called tubercles, which help them move gracefully through the water without meeting too much resistance, drag, or friction.
Interestingly, other animals that swim the oceans have adaptations that help them avoid friction, too. Sharks have tiny scales, called denticles, on their skin that help reduce friction when swimming. Mackerel have sharp, tiny fins on the trunk of their tail that help reduce friction when moving their tail during swimming. Examples of friction-reduced surfaces can also be found in the sports that we play. A golf ball has many dimples covering the surface that help reduce drag, enabling the golfer to hit the ball farther. The one thing that all these have in common is a textured surface structure.
Biomimetics is when a man-made object is engineered by modeling a natural object in the hope that the function of the man-made object will improve. In this experiment you will test different textured surfaces like those found on humpback whales and shark skins to see if they can improve the design of a simple wing. You will use a very simple flying object made of paper, called a whirlybird. Which design will reign supreme, the whirly-bird or the whale-y-bird?
Experimental Procedure and Additional Information
Used with permission. Copyright © 2002-2006 Kenneth Lafferty Hess Family Charitable Foundation. All rights reserved.
Lock, Carrie. 2004. Are propellers fin-ished? Science News for Kids (Sept. 15). Available at http://www.sciencenewsforkids.org/articles/20040915/Feature1.asp .
Sohn, Emily. 2004. Inspired by nature. Science News for Kids (Nov. 3). Available at http://www.sciencenewsforkids.org/articles/20041103/Feature1.asp .
For more science project ideas, go to http://www.sciencebuddies.org/mentoring/areas_of_science.shtml .
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