You know that friction also causes heat. Think about when you rub your hands together. It is friction that makes them warm. But why does this happen? Friction causes the molecules on rubbing surfaces to move faster. Faster moving particles have more heat energy. Heat from friction can be useful. Can you think of other places where you might find friction? Friction also lets you light a match. Heat from friction can also cause problems. It can cause a car to overheat. To reduce friction, oil is added to the engine. Oil coats the surfaces of moving parts. This coating of oil makes them slippery. When things are slippery there is less friction. Have you ever seen a sign that says, slippery when wet? This too has to do with friction. Water, like oil, can reduce friction. The wet surface may allow your shoes to slide more easily.

Question: "What can be done to prevent friction problems in engines?"

Response: "Antifreeze is added to the engine"
OPTIONS:
- no
- yes

A: no

Chinese Influences: The Japanese were forced out of the Korean peninsula in the sixth century, but not before the Koreans had bequeathed to the Yamato court copies of the sacred images and scriptures of Chinese Buddhism. Just as Christianity introduced Mediterranean culture into northern Europe, so Buddhism brought Chinese culture into Japanese society. Throughout the seventh and eighth centuries numerous Japanese monks, scholars, and artists made the perilous trip west across the Sea of Japan to study Chinese religion, history, music, literature, and paintinglater to be brought back for further development in Japan. An outstanding figure of this time was Prince Shotoku, who in 604 developed the "Seventeen-Article Constitution," outlining a code of human conduct and the ideals of state as a basic law for the nation. He also established relations with the Sui dynasty in China. Through him, the Japanese imperial court developed Chinese patterns of centralized government, with its formal bureaucracy of eight court ranks. The Chinese calendar was used to calculate the year of Japan's foundation by counting back the 1,260 years of the Chinese cosmological cycle. Thus, 660 b.c. is still the official date celebrated nationwide. At this early stage in its history Japan was already (for the most part) only nominally ruled by the emperor. De facto power was exercised by the militarily and economically strongest family. The Sogas had promoted Buddhism as an imperially sanctioned counterweight to the native Shinto religion, along with the new Chinese customs, to weaken the influence of their more conservative rivals. But they in turn were ousted in a.d. 645 by Nakatomi Kamatari, founder of the great Fujiwara clan, which was to rule Japanese affairs for hundreds of years and provide prominent advisers to the emperor even up to the 19th century.

Question: "Who helped influence the Japanese imperial court to develop Chinese patterns of centralized government?"

Response: "Scholars"
OPTIONS:
- no
- yes

A: no

Magnets are able to place a force on certain materials. This force is called a magnetic force. The force a magnet exerts is a little different from the forces you may normally think about. You exert a force on a book when you lift it. You also exert a force on the pedals of your bicycle. In both those cases, those forces cause a change. The change you see in both these cases is called motion. Magnets, too, can produce change. They can produce motion just like you do. Unlike you, magnets do not have to touch something to exert a force. A magnetic force is exerted over a distance. Thats right, a magnet can push or pull certain items without ever touching them. Thats how the maglev train works. Do you know another type of force that does not require objects to touch? These forces are known as non-contact forces. Another type of non-contact force you may be familiar with is gravity. Gravity too can cause changes in motion. Gravity holds our moon in orbit without touching it.

Question: "The force that holds our moon in place, is an example of what type of force?"

Response: "Gravity"
OPTIONS:
- no
- yes

A:
yes