Renewable Energy Resource Sunlight Sunlight can be used to heat homes. It can also be used to produce electricity. This conversion is made possible by solar cells. However, solar energy may not always be practical. Some areas are just too cloudy. Example Solar panels on the roof of this house generate enough electricity to supply a familys needs. Moving Water Falling water can have a lot of energy. Its energy can be converted into kinetic energy. This energy can turn a turbine and generate electricity. The water may fall naturally over a waterfall or flow through a dam. A drawback of dams is that they flood land upstream. They can also reduce water flow downstream. Either effect may harm ecosystems. Wind Wind is moving air. It has kinetic energy that can do work. Wind turbines change the kinetic energy of the wind to electrical energy. Only certain areas of the world get enough steady wind. Many people also think that wind turbines are noisy and not very nice to look at. 

What are three ways energy can be generated?


There once was a guy named Kevin and girl named Erin. They really liked spending time together. One day, Kevin traveled from his home in the United States of America to Erin's house in England. They then thought to take a sudden trip around the world. They first traveled by plane around Europe, where they saw many different people and sights. They then took a boat to Africa and Asia, where they went on a trip through the mountains. Later in the month, they traveled to China by train and were allowed to see how different life was over there. Next they took another plane to Australia, where they had a lot of fun seeing kangaroos and a different type of English speaking people. After spending a week in Australia, Kevin and Erin took a really long plane ride to North America, where they drove across the land. They saw everything from the mountains to forests. They even got to visit the beach! Because they had so much fun, Kevin returned home with Erin to England where they hung out and spent the next few days and months talking about all of the neat things they saw and did on their trip. 

Kevin and Erin saw mountains and what two other places on their trip?


Earths magnetic field helps protect Earth and its organisms. It protects us from harmful particles given off by the sun. Most of the particles are attracted to the north and south magnetic poles. This is where Earths magnetic field is strongest. This is also where relatively few organisms live. Another benefit of Earths magnetic field is its use for navigation. People use compasses to detect Earths magnetic north pole. Knowing this helps them tell direction. Many animals have natural 'compasses' that work just as well. Birds like the garden warbler in Figure 1.36 use Earths magnetic field. They use it to guide their annual migrations. Recent research suggests that warblers and other migrating birds have structures in their eyes. These structures let them see Earths magnetic field as a visual pattern. 


Why do few organisms live on the North and South poles?