CSI Episode – Hockey Rink
Scenario:
In a season two episode of CSI, Grissom and Sarah rush to a hockey rink where a murder has taken place. They hope to find some evidence lying on the rink. Unfortunately, a Zamboni machine had already cleaned the ice.
Question:
How does a Zamboni machine dump its ice? One pile? Is it spread out over a large area? How does this work? What is the consistency of this ice? How long would it take for it to melt?
Answer:
We spoke with a lovely woman named Tina at the Zamboni Company who informed that Zamboni dumb their ice in 3X5X5 feet piles, or 75 cubic feet.
We then did some quick internet search, and found that the average temperature of Vegas on a typical night in January is 35 degrees.
Next came the hard part, figuring out how long it would take to melt all this ice. We put together a list of 10 physicists we thought might be able to help.
Eight of them ignored our phone calls and e-mail attempts. One gentleman named Max Godfrey, a scientist from Kent, Ohio was kind enough to call us back. We explained the scenario and within a few hours, he e-mailed a page long mathematical formula filled with words we couldn’t pronounce, much less understand. Besides, there is no way that one of our characters is going to explain a 20-minute mathematical equation in the middle of show. Still he made a few good points about regarding the density of the ice as well as the problem of fluctuating temperature, and wind…
“The air pockets trapped in the compacted snow may act as insulation, preventing the heat from being delivered efficiently to the ice crystals. Likewise, in reality a large portion of the heat put out by the heater will not be delivered to the ice, but will be lost to the air through convection, or to the ground or the already melted water through conduction. Both of these effects will make it take longer to melt the ice.”
Now that we understood the basic principles behind action, all we needed was one good phrase to give the dialogue that special CSI feeling.
We forwarded the paragraphs above to a Chemistry professor at The Cooper Union School for the Advancement of Science and Art. Several hours later he responded with the following statement:
“By combining Foyers’ Law of Conduction with Newton’s Law of Cooling we can get the combined overall heat transfer relationship which when solved will tell us how long it will take for the pile to melt. Still you are dealing with a lot variables such as fluctuating temperature and ice density.”
Finally, research gold. Complicated yet succinct. Perfect.We forwarded this information to writer who then made a few changes and produced the following .