In February 1779, John Adams spent the winter in France and wrote to his wife Abigail Adams:

Why did Europe and the US experience such differences in temperature? In Activities Two and Three, you learned about density and wind-driven ocean circulation. Now you will investigate how the ocean stores heat energy and how some currents, like the Gulf Stream, warm the air. You will also learn how a slowdown of the Gulf Stream could affect the climate of Northern Europe.

In Activity Four, you will explore the differences that still exist between temperatures in Europe and in North America. These differences are due, in large part, to the ability of water to hold onto heat energy and then transfer it to the air above it. In particular, the Gulf Stream is able to hold onto heat energy, transferring it to Europe as it travels east. In Exploring and Discovering, you will compare how well water and sand "hold onto" heat energy. This ability is called specific heat capacity. In Looking Closer, you will look at images of surface temperature in North America and Europe, and explore the temperature differences of cities at the same latitude on both sides of the Atlantic. You will use your knowledge of specific heat capacity to explain any differences that you observe. In Looking Ahead, you will read about how changes in Earth's overall temperature affect thermohaline circulation and how those changes, in turn, affect climate.

Goals

• You will observe which takes longer to heat up and cool down, water or sand.
• You will observe what happens to the heat energy from water and sand as they cool.
• You will learn what happens to the heat energy from the Gulf Stream as it travels north.
• You will learn what might happen to the climate in Northern Europe if the Gulf Stream weakens.
• You will learn that ocean currents and climate are related in complex ways.