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BACKGROUND INFORMATION
The costs of flight are influenced by the relationship between total
wing area
and body mass. In other words, how many grams of mass each unit
area of
wing surface must carry.
To achieve and maintain flight, a bird has to have tremendous muscles.
Over
30 percent of a hummingbird's weight is in its flight muscles. In
fact, the
flapping motion is one of the most strenuous activities in the entire
animal
kingdom. The heavier the bird, the more difficult is flight.
The top weight range of flying birds is about 20 - 30 pounds. Examples
are
mute swans, California condors, and some pelicans. The Andean Condor
weighs 30 lbs., while Bee Hummingbird is only 1.95 grams.
Birds use a great amount of energy for flight, almost 15 times as
much as
when perched on a branch resting. To fuel their muscles, birds eat
high-energy foods and store much of the energy as fat. These energy
reserves are used when food is scarce as well as by migratory birds
that fly non-stop over vast distances of water.
Consider the lifestyle of a bird. It must hunt for food, travel,
protect itself
from predators, and raise a family. Add to these activities, the
high
amount of energy needed for flight. It is no wonder that birds limit
their
flying. In fact there are over 35 species of birds that no longer
fly and
many more that only fly rarely. When not on a hunt to fill their
stomachs,
even our everyday birds limit their flying to conserve energy.
ADDITIONAL ACTIVITIES
To build on wing load and aspect ratio equations students will solve
for
variables practicing with teacher utilizing given data
of another bird or set measures given the following formulas:
Bird Weight / Wing Area=Load
Length / Width=Ratio
After completing practice sessions, teacher will then assign students
to plot the
variables working backwards with the formulas/measures to gain the
correct
variables, or forward to obtain the answer. The educator can obtain
independent
measures for a different species of bird or can utilize the corresponding
measures for the Wandering Albatross, our selected species, plugging
in the
following data:
Median weight of a Wandering Albatross = 20
lbs. which equals 9,072 grams
Wing Load = 1.7 grams/cm² (given)
Bird Weight / Wing Area = Load
Solving for Wing area:
-
9072 grams / A = 1.7 grams/cm²
-
9072 grams = 1.7 grams/cm² (A)
-
9072 grams / 1.7 grams/cm² = A
-
A = Wing Area = 5336.5 cm²
-
Wing area (wing area = wing length * wing width) = 5,336.5
cm²
-
9,072 grams/5,336.5 cm² = 1.7 grams/cm² wing load
Wing Area = Wing Length * Wing Width
Length of a Wandering Albatross Wing = 340 cm
Wing area of a Wandering Albatross = 5,336.5 cm²
Solving for Wing width of a Wandering Albatross:
-
5,336.5 cm² = 340 cm * w (wing width)
-
5,336.5 cm²/340cm = w (wing width)
-
15.7 cm = w (wing width for Wandering Albatross)
-
5,336.5 cm² = 340cm * 15.7 cm
Wing Length/Wing Width = Wing Ratio
Wing Length of a Wandering Albatross = 340 cm
Wing width of a Wandering Albatross = 15.7 cm
Solving for Wing ratio:
- Wing length / wing width = Wing ratio
- 340cm / 15.7cm. = r
- r = 21.7
- Wing ratio = 21.7
Another activity that students may participate in is the paper wings
project.
Materials
- ½ sheet of paper cut lengthwise
- Ruler
- Tape
Procedure
- Fold paper in half widthwise.
- Tape top edge of the paper so that it is about ½ inch
from the
bottom edge. A curve will be created.
- Slide the wing over the ruler, curved side facing you, seam
facing you.
- Hold the ruler in front with the wing hanging down and blow
straight across the folded seam
- The papers will lift because of Bernoulli's principal.
Explanation
There is lower air pressure on top of the paper because the air
is moving faster. Higher air pressure on the bottom pushes up on
the wing.
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