QUES: 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.
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MY QUESTION: Name two benefits of Earths magnetic field.

QUES: It is not enough to describe some objects by their location. We may also need to know its direction. For example, a wind blows a storm over your school. Where is that storm coming from? Where is it going? How can we describe a direction? The most common way is by using a compass. A compass is a device with a floating needle (Figure 2.1). The needle is a small magnet. The needle aligns itself with the Earth's magnetic field. The compass needle always points to magnetic north. If you have a compass and you find north. You can then know any other direction. See the directions, such as east, south, west, etc., on a compass rose. The Earth has two poles. It has a magnetic north pole. It also has a geographic north pole. These two poles are close to each other but not the exact same place.
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MY QUESTION: What might be some characteristics of a storm that we would want to be known?

QUES: Crusaders, Mamelukes, and Turks: The Crusaders established a feudal Christian state with Godfrey at its head. They built many impressive churches during the term of the first Latin Kingdom of Jerusalem, but in 1187 they were driven out by Muslim forces under the great warrior Saladin. During the Sixth Crusade (1228 1229), the Holy Roman Emperor Frederick II managed to secure Jerusalem for the Christians by negotiation. The Christians, however, could not hold the city. After they lost Jerusalem, a Mongol invasion swept through, and in 1244 the Mameluke dynasty of Egypt took control, ruling Jerusalem for the next 250 years. The city struggled to rebuild from Crusader wars and invasions. Much of the best Islamic architecture in the city was constructed in the Mameluke era, but the past thousand years had taken their toll: Jerusalem was unable to regain the prosperity it had enjoyed in earlier times. In the early 16th century, the Ottoman Turkish Empire was advancing through the Middle East. Jerusalem fell to the Ottomans in 1517, remaining under their control for 400 years. Suleiman the Magnificent rebuilt the walls and gates in the form they retain to this day. Fountains, inns, religious schools, and barracks were constructed. But when Suleiman died, his empire, including Jerusalem, began a long period of decline. The Holy City remained a backwater until the 19th century, when renewed interest among Christian pilgrims made it the destination of thousands of travelers each year.
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MY QUESTION: What happened during the Sixth Crusade with the Christians?

QUES: Physical properties include the state of matter. We know these states as solid, liquid, or gas. Properties can also include color and odor. For example, oxygen is a gas. It is a major part of the air we breathe. It is colorless and odorless. Chlorine is also a gas. In contrast to oxygen, chlorine is greenish in color. It has a strong, sharp odor. Have you ever smelled cleaning products used around your home? If so, you have probably smelled chlorine. Another place you might smell chlorine is at a public swimming pool. The chlorine is used to kill bacteria that may grow in the water. Other physical properties include hardness, freezing, and boiling points. Some substances have the ability to dissolve in other substances. Some substances cannot be dissolved. For example, salt easily dissolves in water. Oil does not dissolve in water.
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MY QUESTION:
What are the properties of Chlorine?