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.

Where is Earths magnetic field strongest?

Reducing resource use means just what it says using fewer resources. There are lots of ways to reduce our use of resources. Buy durable goods. Choose items that are well made so they will last longer. Youll buy fewer items in the long run, so youll save money as well as resources. Thats a win-win! Repair rather than replace. Fix your bike rather than buying a new one. Sew on a button instead of buying a new shirt. Youll use fewer resources and save money. Buy only what you need. Dont buy a gallon of milk if you can only drink half of it before it spoils. Instead, buy a half gallon and drink all of it. You wont be wasting resources (or money!) Buy local. For example, buy local produce at a farmers market, like the one in Figure 2.20. A lot of resources are saved by not shipping goods long distances. Products bought at farmers markets use less packaging, too! About a third of what we throw out is packaging.

How does buying only what you need to avoid resource waste?

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.
Who flew in a plane with Erin?