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Math B |
Large Scale
LAB for Creating Sine Curves |
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Here is an idea to consider if you
want to produce a large demonstration of the creation of the sine curve,
or if you want students to develop large display size murals of the sine
curve.
Materials:
butcher-block paper (or large pieces of construction
paper
(the kind that comes on the rolls)
a blackboard compass (or a round bowl for tracing)
a protractor
string
narrow strips of colored paper cut on a paper cutter
(or pipe cleaners, dried spaghetti, string licorice, straws)
markers (might as well make it colorful!)
glue sticks (or scotch tape)
scissors (if using paper strips or straws)
Directions:
1. Lay the butcher-block paper on a flat surface or attach it to a
bulletin board
or wall. If you are using this activity as a demo at
the front board, you can
work right on the board without using the paper.
(If you are doing the demo, have the students come up to do the
measuring.)
2. At one end of the paper, draw a
large circle with a blackboard compass.
Draw a set of axes on top of
the circle.
3. Using the protractor, mark the
circle every 10º (or 15º) starting at 0º.
4. Adjacent to the circle, draw
another set of axes with an x-axis that is the length
of the circumference
of the circle. Use the string to determine the
circumference of the
circle.

5. Place the string around the
circumference of the circle with one end at 0º and
transfer the 10º (or
15º) marks onto the string using the marker.
6. Stretch the string along the
x-axis on the axes to the right and mark off the 10º
increments. You
may wish to also have the students label the axes in radians.
7. Using one strip of paper,
determine the radius of the circle (cut the paper to
match the needed
length).
8. Using two additional strips of
paper, cut the strips to form a right triangle on
the circle where the
radius becomes the hypotenuse. One side is vertical and
the other is
horizontal as seen below.

9. Transfer the vertical paper strip
to the axes on the right and glue it in its proper
degree location.
Magnetic strips of paper can be made ahead of time for use
on a magnetic
blackboard if you are doing a demo (buy magnetic tack-on tape
in any craft
department).
Be careful to position the strip above or below the x-axis depending upon
the
quadrant you are in (if the strip is above the x-axis in the circle,
it will be above
the x-axis on the graph and vice versa.) You may
need to help students figure
out what is happening at 0º, 90º, 180º, 270º,
and 360º.
10. Repeat this process for all of
the degree marks around the circle.
11. When you are finished, you will
have a pictorial representation of the sine
curve (by using the vertical
strips), or the cosine curve (by using the horizontal
strips).

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