Density is also an important physical property of matter. The concept of density combines what we know about an objects mass and volume. Density reflects how closely packed the particles of matter are. When particles are packed together more tightly, matter is more dense. Differences in density of matter explain many phenomena. It explains why helium balloons rise. It explains why currents such as the Gulf Stream flow through the oceans. It explains why some things float in or sink. You can see this in action by pouring vegetable oil into water. You can see a colorful demonstration in this video.

Question: "What physical property of matter combines what we know about an object's mass and volume?"

OPTIONS:
- no
- yes

Answer: "Torque"

Response: no

The one person who, by his interference, could have settled all doubts was debarred by circumstances from interfering in the matter. Wykham Delandre had quarrelled with his sister--or perhaps it was that she had quarrelled with him--and they were on terms not merely of armed neutrality but of bitter hatred. The quarrel had been antecedent to Margaret going to Brent's Rock. She and Wykham had almost come to blows. There had certainly been threats on one side and on the other; and in the end Wykham, overcome with passion, had ordered his sister to leave his house. She had risen straightway, and, without waiting to pack up even her own personal belongings, had walked out of the house. On the threshold she had paused for a moment to hurl a bitter threat at Wykham that he would rue in shame and despair to the last hour of his life his act of that day. Some weeks had since passed; and it was understood in the neighbourhood that Margaret had gone to London, when she suddenly appeared driving out with Geoffrey Brent, and the entire neighbourhood knew before nightfall that she had taken up her abode at the Rock. It was no subject of surprise that Brent had come back unexpectedly, for such was his usual custom. Even his own servants never knew when to expect him, for there was a private door, of which he alone had the key, by which he sometimes entered without anyone in the house being aware of his coming. This was his usual method of appearing after a long absence.

Question: "What happened before Margaret went to Geoffrey's house?"

Response: "She and her brother Wykham had quarreled"
OPTIONS:
- no
- yes

A: yes

Problem: What a time of it Dawson's Landing was having! All its life it had been asleep, but now it hardly got a chance for a nod, so swiftly did big events and crashing surprises come along in one another's wake: Friday morning, first glimpse of Real Nobility, also grand reception at Aunt Patsy Cooper's, also great robber raid; Friday evening, dramatic kicking of the heir of the chief citizen in presence of four hundred people; Saturday morning, emergence as practicing lawyer of the long-submerged Pudd'nhead Wilson; Saturday night, duel between chief citizen and titled stranger. The people took more pride in the duel than in all the other events put together, perhaps. It was a glory to their town to have such a thing happen there. In their eyes the principals had reached the summit of human honor. Everybody paid homage to their names; their praises were in all mouths. Even the duelists' subordinates came in for a handsome share of the public approbation: wherefore Pudd'nhead Wilson was suddenly become a man of consequence. When asked to run for the mayoralty Saturday night, he was risking defeat, but Sunday morning found him a made man and his success assured.

Question: "Whose names and praises were in everyone's mouths?"

Answer: "The town's"

OPTIONS:
- no
- yes
Answer: no

Question:
Duane was hungry, but he hurried through the ample supper that was set before him, urged on by curiosity and astonishment. The only way he could account for his presence there in a ranger's camp was that MacNelly hoped to get useful information out of him. Still that would hardly have made this captain so eager. There was a mystery here, and Duane could scarcely wait for it to be solved. While eating he had bent keen eyes around him. After a first quiet scrutiny the rangers apparently paid no more attention to him. They were all veterans in service--Duane saw that--and rugged, powerful men of iron constitution. Despite the occasional joke and sally of the more youthful members, and a general conversation of camp-fire nature, Duane was not deceived about the fact that his advent had been an unusual and striking one, which had caused an undercurrent of conjecture and even consternation among them. These rangers were too well trained to appear openly curious about their captain's guest. If they had not deliberately attempted to be oblivious of his presence Duane would have concluded they thought him an ordinary visitor, somehow of use to MacNelly. As it was, Duane felt a suspense that must have been due to a hint of his identity. After reading the above, is "Captain" the correct answer to the question "What was MacNelly's rank?"? OPTIONS:
- no
- yes

Answer:
yes

We need natural resources for just about everything we do. We need them for food and clothing, for building materials and energy. We even need them to have fun. Table 2.1 gives examples of how we use natural resources. Can you think of other ways we use natural resources? Use Vehicles Resources Rubber for tires from rubber trees Steel frames and other metal parts from minerals such as iron Example iron ore Electronics Plastic cases from petroleum prod- ucts Glass screens from minerals such as lead lead ore Use Homes Resources Nails from minerals such as iron Timber from trees Example spruce timber Jewelry Gemstones such as diamonds Minerals such as silver silver ore Food Sunlight, water, and soil Minerals such as phosphorus corn seeds in soil Clothing Wool from sheep Cotton from cotton plants cotton plants Recreation Water for boating and swimming Forests for hiking and camping pine forest Some natural resources are renewable. Others are not. It depends, in part, on how we use them.

Question: "What are natural resources needed for?"

OPTIONS:
- no
- yes

Answer: "Building fires"

Response:
no