Italicized links open a new window to an external site

Click here to display our home page

Lesson Ideas
Warm-up Activities
Interesting Numbers

Which is more valuable, a pile of pennies equaling your weight or a stack of quarters equaling your height?

Students who are familiar with pocket change will start thinking about such a question because it seems so simple.  However, using coins to measure human weight and height is a bit strange.  Their first inclination will be to guess, but if you require them to support their answers (by asking an additional question like "By how much?"), they'll soon realize that they need more information. You'll undoubtedly hear questions like, "How much does a penny weigh?" and "How thick is a quarter?".  You can answer them, or show them how/where to get the answers.  In any event I'll bet that you end up with a lively discussion and many involved students.

Here are some resources that will help you and your students go about answering the question.

look at the U.S. Mint's specifications on circulating coins
review the 2004 Guidebook of U.S. Coins by R.S. Yeoman

Excel 97 version (coins97.xls)
Excel 5/95 version (coins95.xls)

Click here to view a GIF image of the spreadsheet running under Excel 97
To return to this page after you finish viewing the GIF image, close the window that will open without closing your browser software.

If you are using Microsoft Internet Explorer 4.01 or later to view this page (and have Office XP or later installed on your system), you can use the Excel worksheet in a separate browser window.  However, if you want to save or print the results of your work, you will find it easier to work with one of the XLS files above.

If this process is too much for your students, urge them to think about and discuss how one would go about solving a problem like this, and what information they'd need to do so.  

U.S. coins

Weight

Thickness

Diameter

grams

mm

mm

=======

=========

========

Penny (1959-82)

3.11

1.55

19.05

Penny (since 1983)

2.5

1.55

19.05

Nickel

5

1.95

21.21

Dime (through 1964)

2.5

1.35

17.91

Dime (since 1965)

2.268

1.35

17.91

Quarter (through 1964)

6.25

1.75

24.26

Quarter (since 1965)

5.67

1.75

24.26

1 inch=25.4 mm             1 pound=453.59237 grams 

To determine an answer for a specific student 

1. for the person's weight 

a. Multiply 453.59237 (the # of grams in 1 pound) by the person's weight
b. Divide the answer from a. by the weight of the coin in grams
c. Divide the answer from b. by the number of coins in one dollar
d. Round the answer from c. to the nearest penny

2. for the person's height with the coins stacked 

a. Multiply the number of feet tall by 12 then add the number of inches
b. Multiply the answer from a. by 25.4 (the number of millimeters in one inch)
c. Divide the answer from b. by the thickness of the coin in millimeters
d. Divide the answer from c. by the number of coins in one dollar
e. Round the answer from d. to the nearest penny

3. for the person's height with the coins laid edge to edge 

a. Multiply the number of feet tall by 12 then add the number of inches
b. Multiply the answer from a. by 25.4 (the number of millimeters in one inch)
c. Divide the answer from b. by the diameter of the coin in millimeters
d. Divide the answer from c. by the number of coins in one dollar
e. Round the answer from d. to the nearest penny


return to the Interesting Numbers page

return to the Warm-up activities page

return to the Lesson Ideas page

copyright 2000-2008 classroomtools.com. All Rights Reserved.
original web posting: Tuesday, March 14, 2000
last modified: Thursday, April 10, 2008