If you build a campfire, you start with a large stack of sticks and logs. As the fire burns, the stack slowly shrinks. By the end of the evening, all that is left is a small pile of ashes. What happened to the matter that you started with? Was it destroyed by the flames? It may seem that way. What do you think happened? The truth is that the same amount of matter still exists. The wood changed not only to ashes, but also to carbon dioxide, water vapor, and other gases. The gases floated off into the air, leaving behind just the ashes. Although matter was changed, it was not created or destroyed. Because the same amount of matter still exists, we can say that matter is conserved. You may wonder how it can be conserved if something is now missing? Assume you had measured the mass of the wood before you burned it. Assume you had also trapped the gases released by the burning wood and measured their mass and the mass of the ashes. What would you find? The ashes and gases combined have the same mass as the wood you started with. This example illustrates the law of conservation of mass.

Question: "Is any matter destroyed when you burn wood in a campfire?"

OPTIONS:
- no
- yes

Answer: "No, because of conservation of mass"

Response: yes

His famous series of sixteen great designs for the Apocalypse is dated 1498, as is his engraving of St. Michael Fighting the Dragon. He made the first seven scenes of the Great Passion in the same year, and a little later, a series of eleven on the Holy Family and saints. The Seven Sorrows Polyptych, commissioned by Frederick III of Saxony in 1496, was executed by Durer and his assistants c. Around 1503-1505 he produced the first seventeen of a set illustrating the Life of the Virgin, which he did not finish for some years. Neither these, nor the Great Passion, were published as sets until several years later, but prints were sold individually in considerable numbers. During the same period Durer trained himself in the difficult art of using the burin to make engravings. It is possible he had begun learning this skill during his early training with his father, as it was also an essential skill of the goldsmith. In 1496 he executed the Prodigal Son, which the Italian Renaissance art historian Giorgio Vasari singled out for praise some decades later, noting its Germanic quality. He was soon producing some spectacular and original images, notably Nemesis (1502), The Sea Monster (1498), and Saint Eustace (c. 1501), with a highly detailed landscape background and animals. His landscapes of this period, such as Pond in the Woods and Willow Mill, are quite different from his earlier watercolours. There is a much greater emphasis on capturing atmosphere, rather than depicting topography. He made a number of Madonnas, single religious figures, and small scenes with comic peasant figures. Prints are highly portable and these works made Durer famous throughout the main artistic centres of Europe within a very few years.

Question: "Which of his works place greater emphasis on capturing atmosphere rather than depicting topography?"

OPTIONS:
- no
- yes

Answer: "His Madonnas and religious figures"

Response: no

When American 11 struck the World Trade Center at 8:46, no one in the White House or traveling with the President knew that it had been hijacked. While that information circulated within the FAA, we found no evidence that the hijacking was reported to any other agency in Washington before 8:46. Most federal agencies learned about the crash in New York from CNN. Within the FAA, the administrator, Jane Garvey, and her acting deputy, Monte Belger, had not been told of a confirmed hijacking before they learned from television that a plane had crashed. Others in the agency were aware of it, as we explained earlier in this chapter. Inside the National Military Command Center, the deputy director of operations and his assistant began notifying senior Pentagon officials of the incident. At about 9:00, the senior NMCC operations officer reached out to the FAA operations center for information. Although the NMCC was advised of the hijacking of American 11, the scrambling of jets was not discussed. In Sarasota, Florida, the presidential motorcade was arriving at the Emma E. Booker Elementary School, where President Bush was to read to a class and talk about education. White House Chief of Staff Andrew Card told us he was standing with the President outside the classroom when Senior Advisor to the President Karl Rove first informed them that a small, twin-engine plane had crashed into the World Trade Center. The President's reaction was that the incident must have been caused by pilot error. At 8:55, before entering the classroom, the President spoke to National Security Advisor Condoleezza Rice, who was at the White House. She recalled first telling the President it was a twin-engine aircraft-and then a commercial aircraft-that had struck the World Trade Center, adding "that's all we know right now, Mr. President." At the White House, Vice President Dick Cheney had just sat down for a meeting when his assistant told him to turn on his television because a plane had struck the NorthTower of the World Trade Center. The Vice President was wondering "How the hell could a plane hit the World Trade Center" when he saw the second aircraft strike the South Tower. Elsewhere in the White House, a series of 9:00 meetings was about to begin. In the absence of information that the crash was anything other than an accident, the White House staff monitored the news as they went ahead with their regular schedules.

Question: "What airplane crash did most federal agencies learn about through CNN, rather than their own internal reporting channels?"

OPTIONS:
- no
- yes

Answer: "They were told it was a helicopter"

Response: no

IBM opened a sprawling and sophisticated semiconductor factory here on Wednesday that cost more than $2.5 billion to build and equip, the largest single capital investment the company has ever made. The factory, which opens as the computer chip business is in a slump, is a costly and risky move for IBM. But it is also an expression of confidence by the company that it can remain a technology leader in the highly competitive global semiconductor industry, and a commitment that the best place to execute that strategy is in upstate New York. IBM is an exception among computer makers in that it still invests heavily in research to advance the design, manufacture and materials used in semiconductor chips. It is spending more than $500 million a year on semiconductor research and development. The factory will produce a wide range of specialized semiconductors used in everything from the largest mainframe computers to cell phones and video-game consoles. The new plant is part of IBM's push to gain a strong lead in chip-making beyond the personal computer business, where Intel and East Asian chip producers hold the advantage. "The core of our strategy is to lead in technology and attack the high-performance segments of the market," said John Kelly, senior vice president in charge of IBM's technology group. An advantage to having the semiconductor fabricating factory here, Kelly explained, was that it was very close to its research laboratories in nearby Westchester County, N.Y. To stay ahead in advanced chip technology, he said, moving innovations out of the labs and into the factory as fast as possible is crucial. "What we call the lab-to-fab time should be as close to zero as possible," Kelly said. "If our strategy were anything but to be on the leading edge, we'd have put the plant in Asia." The new factory, which will begin normal production early next year, will employ about 1,000 people.

Question: "What doe "lab-to-fab" time mean?"

OPTIONS:
- no
- yes

Answer: "Strategy were anything but to be on the leading edge"

Response:
no