(Teaching Colors & Numbers, Even & Odd, Decimal Point & Randomness of Pi)

Activity:

Build a pi chain with loops of construction paper, each digit represented by a different color. Some student projects have build pi chains thousands of loops long.

Suggestions:

(1) Assign a color to each of the ten digits (0-9) and then build a color/number key to post in the classroom.

(2) Have an official “pi reader” call out the numbers as you assemble the chain.

(3) Build the color key by asking students to choose their favorite color, and then assign that color to a number based upon the last digit of the student’s birthday or month of birth. Query the class until all ten digits are assigned.

(4) You may want to also teach about even and odd numbers. Divide the class into two teams, one working with the five even digits for the pi chain and the other with the five odd digits. Students can split based upon their birthday, either the ending digit even or odd of their day-of-birth, or month-of-birth. Or they can split based upon whether their first or last name has an even or odd number of letters.

(5) When building the chain, choose a very special 11th color (perhaps foil paper) to represent the decimal point and discuss its concept.

Activity:

For younger students, explore items round versus square/rectangular in the real world. It is interesting that in nature round is common, square/rectangular are virtually non-existent. Civilization is a mixture of both. Are circles more “natural” than squares and rectangles? Which is easier to measure? Have students do a scrap book or bulletin board of pictures of things round, and same of things square/rectangular.

Suggestions:

(1) Make a list of many things in nature that are round (from planets to tree trunks to the iris of the eye) and square/rectangular (that is a hard one, perhaps a few crystals but little else in nature is square except by chance).

(2) Make a list of things created by civilization that are round and things that are square/rectangular.

(3) Coins are round. Paper currency is rectangular in shape. How many circles can you find printed on the $1bill? How many squares are printed on the $1 bill?

(4) Look for round versus square/rectangular things in sports. Round includes basketballs and hoops, hockey pucks, soccer balls, baseballs, the center circles of basketball courts and soccer fields etc. Square and rectangular includes chess boards, basketball courts, football and soccer fields, tennis courts, first/second/third base in baseball. Is any one sport all round or all square?

(5) Is food more often round or square/rectangular?

(6) What is the difference between a well-rounded person and a square?

Activity:

Challenge your students to freehand draw a perfect circle on a sheet of paper or on the class' chalk board. Have the class vote on the winner.

Suggestions:

Have the class add a radius line and then extend it to become the diameter to familiarize those terms. Use a compass to trace a more accurate circle overlay to familiarize students with the compass. Use pi to calculate the area of each student’s circle under the assumption that it was perfectly drawn.

Activity:

The center circle and bisecting midline of the basketball court and soccer field make perfect large scale pi labs. If you have access to either, have the students measure both the circumference and diameter and show in the real world how the circumference is just over three times the length of the diameter. This visualization could last a lifetime with every basketball and soccer game serving as a reminder.

Suggestions:

It may be easiest to measure with a simple segment of rope cut to the length of the diameter, and carefully laid down about the circumference three times with a small (.14) gap trying to complete circle. If it is indoors or the weather is good outdoors, have the students take off their shoes and lay them along the diameter, and then use the same sequence of shoes to measure the circumference placing them down three times with a small gap left over. Could this be how the English gave the world the “foot” unit of measurement? (Your results may vary slightly due to measurement inaccuracies.)

Activity:

Pi goes on forever in random numbers never repeating itself. It is both an irrational and transcendental number. Pi has been computed to over one trillion digits and counting. If you and your students have access to the internet, a really fun website called Pi Searcher -- www.angio.net/pi/bigpi.cgi -- enables you to quickly search any sequence of numbers (phone numbers, birthdays, your street address, Zip Code etc.) among the first 200 million digits of pi to right of the decimal.

Suggestions:

Here is a chance to play with the first 200 million digits of pi and realize the awesome power of a number that goes on theoretically forever without repeating itself. (1) Have students search their birthdays' six digit numeric expression (MMDDYR). Find out whose birthday in the class is earliest in pi, whose is latest to first appear among the first 200 million digits of pi. (Note that there is a very small chance that a six digit string will not appear in the first 200 million digits of pi so keep a consolation prize handy..) (2) Students can express their initials or name numerically by the letters’ place in the alphabet, and then search the numeric string in pi. For example, using Albert Einstein's first initials "A" and "E" gives the sequence 1, 5:

A = 1 (first letter in the alphabet)

E = 5 (fifth letter in the alphabet)

The sequence 1, 5 occurs at position 3 of pi to the right of the decimal. (Note: many mathematicians love to point out that Albert Einstein was born on March 14, which can be numerically expressed as 3.14 which equals pi!)

Activity:

Bring to class one or more large circular items such as a bicycle wheel, hula hoop or plywood disc (available a many home improvement centers). Physically measure the circumference of your circular object by marking the round item along the outside edge, and rolling it on the floor one full revolution to convert the circumference into a straight line. Next measure the diameter by finding the absolute widest measurement across the circle. Lay the diameter measurement onto the circumference line and it should go slightly more than three times. (Your results may vary slightly due to measurement inaccuracies.)

Activity:

Hold a competition to see who can memorize and recite the most digits of pi.

Suggestions:

One memory tool is to create a sentence using words whose number of letters correspond to the numbers of pi, such as the following sentence which covers the first 15 digits (3.14159265358979) of pi: How(3) I(1) need(4) a(1) break(5), mellowing(9) in(2) nature(6), after(5) the(3) heavy(5) lectures(8) involving(9) quantum(7) mechanics(9). Challenge your class to try and construct a similar sentence, or add on to the above example and take it out to at least 20 digits (the next five pi numbers are 32384). Only 20 digits of pi are necessary to calculate the circumference of earth down to a fraction of an inch. For that matter, some mathematicians theorize that the first 39 digits of pi are all that are needed to calculate the circumference of the entire known universe down to the electron!