What is the water cycle? The water cycle is the repeated movement of water through Earth’s environment. Water changes form as it moves through the water cycle. There are four major processes in the water cycle. These processes are shown in a diagram on the next slide. Evaporation: The changing of a liquid into a gas. Liquid water evaporates to form water vapor in the atmosphere. Condensation: The changing of a gas into a liquid. Water vapor condenses in the atmosphere to form clouds. Precipitation: Water that falls to Earth as rain, snow, sleet, or hail. Runoff: A small amount of precipitation lands on the surface and runs off into streams and lakes. (contd.)

Science notebook: text should be roman, not ital Science notebook: text should be roman, not ital. Number s/;b black (I can’t tell if it is or not at maximum zoom.) 1. Summarize In your notebook, create your own diagram of the water cycle.

How does the sun affect the ocean? Energy from the sun affects the temperature of the ocean and how water moves within it. Water evaporates from the ocean surface and condenses to form clouds. Energy from the sun heats the ocean. The more directly the sun’s energy hits an area, the warmer the ocean temperatures. Places near the equator are usually warmer than places near the poles. When one part of Earth is tilted toward the sun, that part receives more solar energy. The ocean there will be warmer. (contd.)

Energy from the sun causes air to move. This causes winds to blow Energy from the sun causes air to move. This causes winds to blow. The winds move water in the ocean, forming currents. The currents can change ocean temperatures. Currents carry warm water from the equator toward the poles. Other currents carry cool water from the poles toward the equator. (contd.)

Sometimes wind patterns change over the Pacific Ocean Sometimes wind patterns change over the Pacific Ocean. These changes can cause a huge area of warm water to move. This warm water keeps colder water from coming to the surface. This change is called El Niño. El Niño affects weather in many parts of the world. Water in the Pacific can also be colder than normal. This causes La Niña. La Niña can bring colder weather to some areas. These computer images show the differences in water temperature between a normal year (top) and an El Ninõ year (bottom). 2. Explain How does the sun’s energy cause ocean currents?