PURPOSE: To illustrate exponential increase from 1 through 2⁶³.

DESCRIPTION: The transparent chessboard serves as the starting point for the progression. Rice can be put on the chessboard for 1 through 2⁵ (32) grains. Use beakers for 2⁶ through 2¹⁷ grains. (Note: 1 ml = 64 grains, approximately.) The approximate volume of rice for successive powers of two are:

2¹⁸ - 2²⁰: small waste basket, to 5.6, 11, and 22 cm, respectively.

2²¹ - 2²²: large waste basket to 31 and 62 cm, respectively.

2²³ - 2²⁷: area of 1mx2m lecture table to 6.5, 13, 25, 50, and 100 cm, respectively.

2²⁸ - 2³⁷: area of front of room to 1, 2, 4, .......512 cm, respectively.

The total amount of rice is 2⁶³ - 1, or about 9.2x10¹⁸ grains. This is approximately four crops at 100 bushels per acre, with the entire land area of earth (about 4x10¹¹ acres) planted with rice!

SUGGESTIONS: Tell them the story about the invention of chess.

REFERENCES: (PIRA unknown.)

EQUIPMENT: Rice, labeled containers through 2¹⁶, transparent chess board.

SETUP TIME: 5 min.