Low-Cost Competition

Apparatus Title: Color Cubes for Decay Simulation

Abstract   A simple method for mass producing uniformly sized and colored cubes is presented. These cubes are used to simulate the decay of radioactive nuclei. The coloring scheme of the cubes either reenforces or introduces the three primary colors (both additive and subtractive.)

Equipment required to construct apparatus:

Band saw or table saw with thin blade (veneer)

Item Source/Store Part Number Cost

• four 1/4 inch sheets of clear poplar 6" x 24" hardware store $20.00
• six cans of spray paint hardware store - red - green - blue - cyan - magenta - yellow $30.00
• Masking tape Hardware store $ 2.00

Sketch of the apparatus:

Description:

In order to economically make a few thousand inexpensive 'dice', the following method was undertaken. Sheets of clear poplar, 1/4 inch thick were found at the local building supply store. One side of the sheet was spray painted yellow and opposite side, blue (dark blue, NOT cyan).

Color pairs were chosen so that the opposite faces of the final dice would be complementary. In other words, the sum of the colors on opposite sides will be white, just as the sum of the spots on opposite sides of conventional dice is seven.

Once the sheet is thoroughly dry, it is 'ripped' into long thin strips, each 1/4 wide as well as 1/4 inch thick. The width of the strips should be controlled as accurately as is convenient to be 1/4 inch.

Masking tape is now used to 'reform' these strips into a single sheet, but each strip is first rolled 90 degrees so that the painted faces are concealed. Two more complimentary colors are used to paint the next two exposed sides. e.g. cyan and red.

Once the cyan and red surfaces are both dry, the sheet of sticks is COMPLETELY taped on both surfaces, preparing it for the final 'dicing' operation.

The final saw cuts are made perpendicular to the previous cuts and again, the width of the resulting strips should be as close to 1/4 inch as practicable. The resulting short sticks of cubes need to be handled fairly carefully while being assembled side by side, bare faces exposed, for the final two colors to be applied.

Removing the tiny squares of masking tape from the resulting 'Color Cubes' is a tedious task that student labor can accomplish!

A typical class exercise will be for each group of two students to begin with about 100 cubes. They must choose one of the colors that will decay BEFORE the cubes are tossed onto the table.

The usual statistics are collected and a graph of surviving number of cubes versus number of tosses is created.