The Jakobshavn Glacier is very likely the source of the iceberg that sank the Titanic in 1912 and researchers focus on it because it discharges nearly 7% of all the ice coming off Greenland. As the planet warms, its melting ice sheet could make oceans rise this century.

Scientists do not know how melting water moves through the ice. One theory is that the summer sun melts ice on the top glacial surface, creating pools that flow into tubular holes in the glacier called moulins. The moulins can carry some water all the way to the underside of the glacier, where it acts as a lubricant to speed the movement of ice toward the coast. But because it cannot be seen, no one really knows what occurs. That is where the rubber ducks come in, along with a probe about the size of a football loaded with a GPS transmitter and instruments that can tell much about the glacier's innards. The ducks, if they are found and if somebody e-mails the discovery, would tell scientists where the water ends up.