Static electricity is like a teeter-totter. What happens if a teeter-totter is balanced? Correct! It does not move. What about when its not balanced? Yes, it will now begin to move. Charges move when they are not balanced. Charges can build up by friction. Maybe you rub your feet on a wool mat or carpet. Rubber soled shoes readily gain charges. The wool carpet easily gives up charges. The two items become unbalanced. One item has a positive charge. The other has a negative charge. The difference in charge is called static electricity. Just like the teeter-totter, something is going to move. Positive charges build up on the mat. Negative charges build up on you.

Question: "What kind of charge is required for static electricity?"

Response: "Both positive and negative"
OPTIONS:
- no
- yes

A: yes

The inhabited history of the Las Vegas Valley stretches to 23,000 b.c. , when much of the area was covered by a prehistoric lake. During this period, the indigenous people lived in caves, hunting the mammals that gathered at the shoreline. The landscape of the valley changed dramatically over the next 200 centuries. The glaciers feeding the lake melted away and the lake evaporated. Fossils tell an obscure story of man's slow and sporadic development. Around 3000 b.c. , native Archaic Indians began to develop a lasting hunting and gathering culture. By this time, the valley was in much the same geographic state as it exists in today, with one exceptionthe presence of artesian springs that bubbled to the surface in several areas. These springs fed a network of streams draining through the Las Vegas Wash to the Colorado River. The areas surrounding the springs were desert oases: sprawling collections of grasses, trees, and wildlife. Many springs lay in areas that would eventually become the center of the modern Las Vegas metropolis. For about 4000 years, the Archaics thrived in a culture that included many signs of early civilization. Signs of even more advancement appeared halfway through the first millennium a.d. , when the Anasazi Indians inhabited the valley. Far more progressive than the Archaics, the Anasazi utilized such formal agricultural techniques as irrigation to assist their harvest. This permitted the Anasazi to achieve a benchmark of advanced societythe ability to live in permanent shelters year-round without need to follow wildlife. Mysteriously, the Anasazi vanished from the valley around a.d.

Question: "Who was the most advance early civilization that disappeared in Las Vegas?"

Response: "Cherokee"
OPTIONS:
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- yes

A: no

We waited for half an hour, watching the smoke curling over the house, and then, judging that the Indians had made off for fear of being ambushed, we crossed the clearing. It took but a glance to read the story. The women had been washing by the little brook before the cabin, with the children playing about them, when the Indians had come up and with a single volley killed them all except the child we had heard crying. They had swooped down upon their victims, torn the scalps from their heads, looted the house, and set fire to it. We dragged out the body of the woman which had been thrown within, in the hope that a spark of life might yet remain, but she was quite dead. Beneath the warrior Spiltdorph had shot we found the child. It was a boy of some six or seven years, and so covered with blood that it seemed it must be dead. But we stripped it and washed it in the brook, and found no wounds upon it except in the head, where it had been struck with a hatchet before its scalp had been stripped off. The cold water brought it back to life and it began to cry again, whereat Spiltdorph took off his coat and wrapped it tenderly about it.

Question: "Who had a name in the story?"

Response: "Spiltdorph"
OPTIONS:
- no
- yes

A:
yes