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OBJECTIVES:
Biomechanics is an "interdisciplinary field" combining
several different sciences.
A sport biomechanist is a scientist or researcher that studies
human motion or sports performance.
Knowledge of biomechanics is important in the sports industry for
those who design equipment.
In this activity, you will build
a model of a human arm
and shoulder. The model will demonstrate
that these body parts act like
different types of mechanical joints and that muscles "pull" but do not "push".
Using a hinge for the elbow, a universal joint for
the wrist and a ball and socket joint for the shoulder,
you will build a mechanical model of an arm. You
will use a small tag board cutout for the hand,
a small block of wood for the wrist, chopsticks for
the forearm, a longer block of wood for the upper
arm and string for the muscles.
STEPS TO FOLLOW:
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Use the pattern of the hand and trace it onto the tag board. Cut out
the tag board hand.
From the 1/4" diameter dowel cut two 1/2" lengths.
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Place tarps on the table. Lay your materials in the
proper order to prepare to construct your mechanical arm (the
hand, small dowel, the universal joint, small dowel,
small piece of styrofoam, chopsticks, the paper hinge,
the long block of wood and the ball and socket joint). Put on gloves.
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Fold the paper hinge in half. Open and close the hinge a few times to ensure it
is flexible. Glue half of the hinge to the long block of wood. Let it dry.
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While you wait for the hinge to dry, push one dowel into the universal joint. P
ush the other dowel into the other end of the universal joint.
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MATERIALS:
For Each Student:
1 Pair Of Vinyl Gloves
1 Pair of Chopsticks (Attached To One Another)
30 Inches Of String
1 Paper Hinge (Can Be Found At A Hobby Store)
Styrofoam - 1 Inch x 1/2 Inch
Block Of Wood - 1 inch X 1 inch X 3 Inch
1 Ball And Socket Joint
1 Universal Joint
1/4" Diameter Dowel At Least 1 Inch Long
Tag Board
Hand Pattern
Disposable Tarp or Tablecloth
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Push the other end of one dowel (now attached to the universal joint) into the wrist portion of the hand. Push the other end of the second dowel into one end of the styrofoam. Move the mechanical wrist. How does the range of motion of your mechanical wrist compare to your own wrist?
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Glue the other half of the hinge to the wood which attaches the two chopsticks. Let this dry. Once it is dry, move your mechanical elbow. How does the range of motion of your mechanical elbow compare to your own elbow?
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Push the chopsticks into the other end of the styrofoam to attach the "chopstick forearm" to the "mechanical wrist".
Make the shoulder joint. Push the ball and socket joint onto the top of the larger block of wood.
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Thread one strand of string between two staples on one side of the mechanical arm. Thread the second strand of string between the two staples on the other side of the mechanical arm.
Pull the string to bend the arm. Pull the other string to extend the arm.
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