Franklin-Folger 1769 chart of the Gulf Stream. Reproduced with permission from US Library of Congress.

Ages and ages ago, man was motivated to learn more about the ocean because he needed to get his outrigger across a tidal inlet, or through some surf, or across an ocean. Through the centuries navigation remained the driving force behind the desire to learn more about the sea and its swift, and at times terrible, currents. Today, people swim in the Atlantic Ocean or fly over it on their way to Europe. But in colonial times, the Atlantic Ocean was a barrier to visiting family, conducting business, buying goods, and receiving mail. The route that ship captains took and the weather conditions they encountered could make the difference between life and death. Storms could easily sink wooden sailing ships. Getting caught in a slow-moving current or in a windless stretch of ocean could mean running out of food or fresh water. Eighteenth-century captains needed to know which currents to sail in and which ones to avoid.

Benjamin Franklin was interested in ocean currents. To learn about the North Atlantic Ocean and its most powerful current—the Gulf Stream—Franklin took temperature readings on his ocean voyages, published charts of the current, and wrote scientific papers sharing his findings. You will read about Franklin's charting of the Gulf Stream and travel in colonial times.

Ben Franklin and the Gulf Stream by Maurice Isserman

Atlantic Ocean Historic Timeline

History of Mapmaking

Courtesy NOAA/NASA.

Today, with the help of satellite technology, scientists can collect a variety of data about the Gulf Stream and other oceanic features. Satellites help these scientists in many ways. Some satellites take pictures of Earth as they fly overhead. Others receive data transmitted from buoys that scientists have placed in the ocean. Satellite sensors collect data that allow scientists to observe details of the ocean’s surface. Some sensors are similar to cameras, capturing visible light, while other sensors detect energy that we cannot see with our eyes, such as infrared radiation. Buoys are also used to collect data. Scientists set buoys afloat in the ocean equipped with instruments that can measure different variables including temperature, salinity, and wind speed. The data is transmitted along with the buoys' location to a satellite. By looking at the different types of information, scientists can start to paint a more complete picture of the Gulf Stream and its constant motion and change.

Goals

1. You will describe how six images of the Gulf Stream were created. You will figure out what each image can tell you—and what it can’t.
2. You will learn how modern technology increases the type and quantity of information that scientists can collect about Earth’s oceans.