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Using Spheres to Examine Changes in Volume and Surface Area
In this activity, balls will be
used to set the tone for an investigation of how changing the radius
of a sphere affects its surface area and volume.
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The introduction to this activity can be
done as a teacher demonstration in front of the class (with class
discussion), or as a student group activity. If done as a group
activity, where students are supplied with balls, be ready for some
bouncing. Set the ground rules before handing out the balls.
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Introduction:
Supplying students with balls:
Balls can be purchased at the local "Dollar Store" or you may be
able to get them on loan from your physical education department.
While varying size is not a requirement, it would allow for more
discussion. Materials per group: ball, string,
ruler, calculator. When the students finish gathering their
data from the balls, collect them back.
Teacher demonstration:
If you do not have the time for a group activity, a
teacher directed demonstration will work nicely. Be sure to
use a large ball, such as a basketball, so that the entire class can
see what you are doing.
"I would like to examine
the volume and surface area of this ball.
How would I go about doing that? What would I need
to know?"
Have this discussion before handing out the worksheet.
Use a piece of string to measure the
circumference. Supply the class with this number
and ask them to find the radius, volume and surface area
(given the last two formulas). |
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Calculations:
Students will complete a
chart of calculations regarding volume and surface area of spheres.
These calculations will be used to formulate hypotheses regarding
how changes in the radius will affect the volume and surface area of
a sphere.
Note: This
activity could also be done with cubes.
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Download Worksheet:
Download the worksheet for this
activity for use in your classroom.
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