If Junior’s science fair project is due tomorrow, there’s plenty of time for him to take home the blue ribbon, as long as there is snow on the ground. The science teacher demands that the experiment answer a question, so Junior’s question will be: “Which melts faster–clean snow or dirty snow.”

It turns out that the dirty snow will melt faster. This is because the dark particles soak up heat, while the pure white snow reflects it. To prove it, Junior can set up the experiment shown above.

You will need a table lamp with an old-fashioned incandescent bulb. For this experiment, you do not want an “energy efficient” bulb. They are energy efficient because they generate less waste heat, but for this experiment, you want to generate heat. So the most inefficient bulb wins.

To accurately measure the rate of melting, the snow is placed on a piece of screen on top of a glass. There are two ways Junior can do the experiment. He can wait until all of the snow melts, and see which one melts first. Or, he can stop the experiment after a certain time and measure the water to see which one has more.

The teacher will be most impressed with Junior’s ingenuity. He or she will think that many weeks of planning went into it. Actually, 80 years of planning went into it, since the experiment appeared in the December 1939 issue of Popular Science.