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.

Question: "How do garden warblers use the earth's magnetic field to guide animal migration?"

OPTIONS:
- no
- yes

Answer: "Direction"

Response: no

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.

Question: "What are 3 sources of renewable energy"

OPTIONS:
- no
- yes

Answer: "Moving water, wind and the sun are sources of renewable energy"

Response: yes

Expansion quickly peaked however, and the European powers who had carved up the New World set about testing each other in dynastic conflicts and colonial rivalry. The English were the main rivals of the Dutch on the high seas, and there were several wars between the two in the 17th and 18th centuries. In 16651667 the Dutch sailed up the River Medway and sank the British fleet moored there. The 18th century saw Amsterdam grow into the foremost financial center in the world, but the seeds of decline had already been planted. When the English colonies in New England rose up in revolt against the British, they found ready Ailies in the Dutch. From their colonies in the Caribbean they sent caches of arms and ammunition. The British were furious and went to war in 1780, destroying the Dutch navy and signaling a sudden decline in power and influence from which the Netherlands never recovered. Trade suffered to such an extent that in 1791 the VOC went into liquidation. In the latter part of the century there were anti-Orange demonstrations by pro-French factions in the country, and in 1795 Napoleon Bonaparte took the Netherlands in his epic march across Europe. Under the yoke of another foreign power, and with trade at an all time low, the Golden Age was truly dead. The Return of the House of Orange Napoleon installed his brother Louis as King of Holland and he chose to take the fine Town Hall on Dam Square as his palacenow the Koninklijk Palace. But only four years later he fled the city after civil disturbances broke out when he raised taxes. When Napoleon's bubble burst and French power began to wane, William of Orange emerged from exile and was proclaimed king in 1813. Amsterdam had to work its way out of economic decline, but throughout the 19th century the city grew steadily. Industrialization changed the city. With the building of the Central Station at the end of the century, Amsterdam turned its back on its seafaring past and looked towards the mechanical age for its future. The station was built over the old harbor wall and some of the oldest canals in the city center were filled in to allow better access to motorized vehicles. Dam Square was landlocked for the first time in its history.

Question: "What caused Dam Square to become landlocked for the first time in its history?"

OPTIONS:
- no
- yes

Answer: "When Louis was installed as King and took the Town Hall on Dam Square as his palace"

Response: no

Take a look at this train in Figure 1.11. It looks very futuristic. What do you notice about it? Did you notice that the train has no wheels? How can a train have no wheels? It doesn't need wheels. It actually floats, or levitates, just above the track. Magnets enable the train to do this. This is not a normal train. This is a maglev train. The word maglev stands for magnetic levitation. Because it has no wheels, there is no friction. Some magnets hold the train up. Other magnets are used to move the train forward. This train can go very fast. It can reach speeds up to 480 kilometers (300 miles) per hour! Magnets are pretty cool. What exactly is a magnet? How is it able to exert such force?

Question: "What holds the train up and moves it forward?"

OPTIONS:
- no
- yes

Answer: "Conduction"

Response:
no