Listen to part of a lecture in an earth science class. Okay, before we finish class, I\'d like to briefly talk about something else. Has anyone ever heard of something called flotsam science? No. Well, I\'m not surprised. It\'s a research method, but one of the more unusual ones out there. Now, flotsam, of course, refers to cargo or wreckage from ships that\'s found floating at sea or washed up on shore. Flotsam science began quite accidentally, some years ago a shipment of plastic bath toys shaped like frogs, ducks and turtles fell off a cargo ship into the Pacific Ocean in stormy weather. No one thought too much of this. It happens all the time. But then these toys started to wash up onto beaches 1000s of miles away. Scientists who track ocean currents were static. Since they knew when and where that spill had occurred they realized they could trace the roots these toys had taken as they floated through the Pacific. So flotsam science is generally speaking the science of floating junk but this is a legitimate, if perhaps unconventional scientific discipline. In fact, thanks to flotsam science and these traveling bath toys and other harmless stuff that drops off ships like athletic shoes, sports equipment, you name it scientists now know a lot more than they used to about currents in the Northern Pacific. That information, in turn, has allowed scientists to identify long term changes in water temperatures and salinity of the amount of salt in the water in these currents before flotsam science, scientists had been trying to determine this information years by using expensive scientific devices that they would set adrift in the ocean. But there are problems with these devices. For one thing, they need to travel at great depths, as much as two kilometers down because if they ride on the surface of the ocean, their sensors can become obstructed by algae, barnacles and other organisms that thrive in the sunlit upper portion of the ocean. But if they travel way below the surface to avoid these obstructions well, they don\'t tell you much about the surface movement of the water which is what we want to know. Another problem is that their batteries don\'t last long enough to record sufficient data but bath toys and athletic shoes and this sort of thing they travel on the surface, and they don\'t need batteries and a lot of merchandise that falls off ships, like athletic shoes have manufacturing codes on them that scientists use in tracing the origin of these objects and keeping track of their movements. And now scientists are using flotsam science for more than studying ocean currents. For example, some scientists are trying to use lots of science to study glacial melt water in the warmer summer months. From the top layer of a glacier melts, forming pools of melt water. So far, it\'s been a challenge to determine just how much is a glacier loses each summer or where the meltwater winds up because it travels through Moulins. A moulin is a giant crack in the glacier that melt water drains through and once melt water enters a moulin it\'s extremely difficult to track. One scientist set out to determine where melt water from a glacier in Greenland ends up into which neighboring body of water. So what this scientist did is he set a special scientific instrument equipped with a tracking device down a moulin in Greenland\'s largest glacier. Unfortunately, his rather expensive device disappeared. Okay, so what else could be used? Now you have to realize that conditions inside these moulins are intense. It\'s freezing cold, plus there\'s the high pressure from the weight of all that ice above. So what was needed was something really durable. He finally decided to use yellow ducks a children\'s bath toy their advantage being that they\'re both cheap and can withstand high pressures and low temperatures. Well after printing his email address and an offer of a reward in three different languages on the ducks he dropped 90 of them down the Moulin he was researching. Now he hasn\'t actually had any of these ducks returned yet but he remains hopeful that someone will find a duck and return it to him.