In this activity students will measure various
dimensions of a male and a female doll's body and scale
them proportionally to average human measurements.
They must calculate the appropriate scale factor
(magnitude) to enlarge their doll and apply that scale
factor to enlarge the other measurements. Once completed, the students
will analyze and describe the enlargements, as well as explore the
commercial and social implications of the dolls' designs.
LESSON PLAN
Have students work with a partner or in groups. Instruct them to take the
following measurements of both Barbie™ and one male action figure:
height, head (circumference), chest, waist, inseam, and foot (length). The
measurements are written in the first blank column of each of the charts.
The numbers already given in the chart are the average measurements for
females and males. The students will use these numbers to calculate their
size change magnitudes.
Once students have completed the measurements, walk them through the
first conversion, using height to be the first standard. For example, if Barbie
is 12 inches tall and the average woman is 65 inches tall, what would the
other enlarged measurements be? Divide 65 by 12, to get a ratio of 5.6,
then multiply each of the measurements by this ratio. Emphasize that this
represents one "possible" body shape. The next conversion will use 21
inches as the standard for the head. Calculate this new ratio and repeat the
process. This represents another "possible" body shape.
After the walk through, allow the students to complete the chart by calculating the conversions for the other
standards. Reinforce that each column is one possible enlargement of the doll and that the body shape
enlargements will not always come out looking the same.
To conclude the activity, the students should summarize their findings, and make conjectures in
regards to why manufacturers chose the particular proportions of the dolls. There are four
questions on the handout to guide the students in their analysis.
TEACHER COMMENTS
• Stress that each column in the chart is considered a different enlargement. Emphasize that for
#1, you might be enlarging the doll to an average height, but for #2 you are enlarging the
doll to an average head.
• It is helpful to model an example of the lab before the students begin. With a doll and tape
measure, show them how to measure the doll's attributes, fill in the chart, calculate the
magnitude, and enlarge all the measurements.
• The primary concept here is ratio and proportion, which can be dramatically demonstrated by
comparing the bodies represented in each column. For example, at average height, Barbie has
a large head with small feet, which means she cannot stand. (She could not at doll size, either.)
Given an average foot size, her height is gargantuan, as is her head, yet her feet still are not big
enough to support her. This is because each attribute of her body was multiplied by the same
ratio; in other words, each body enlargement is proportional to the others.
Concepts
Ratios, proportions, similarity,
measurement, Fundamental
Theory of Similarity (optional)
Time: 1-2 days
Materials
An assortment of Barbie dolls
and action figures (Batman™,
G.I. Joe™, Power Rangers™,
etc.) Student Handout
Preparation
Tell the students in advance to
bring dolls and action figures
on the day of the lab. It helps
to offer an incentive for the
students (extra credit, etc.)
Each group will need one male
and one female doll. It will be
helpful to have extras on
hand.
MPJ’s Ultimate Math Lessons 3
STUDENT HANDOUT
If Barbie™ was the size of an average woman and Batman™
an average man, what would they look like?
First, find two dolls or action figures (one male, one female) and measure
various attributes of their bodies (see charts below). Second, calculate an
appropriate scale factor to enlarge a certain dimension to a certain size. For
example, in the chart below, the height of the average male is listed as 72
inches. After you measure your male doll, multiply the figure's measurements by some factor in order
to enlarge it to 72 inches. Then use that scale factor to determine the other enlarged measurements.
You will perform this process several times for each figure. The numbers provided are the hypothetical
average measurements for females and males.