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 does density tell?"

OPTIONS:
- no
- yes

Answer: "How closely packed the particles of matter are"

Response: yes
Triumph and Disaster: The 20th century saw a stupendous release of energies that had been pent up for the 250 years of Tokugawa isolation. By 1930 raw-material production had tripled the figure of 1900, manufactured goods had increased twelve-fold, and heavy industry was galloping towards maturity. Britain led the World War I Ailies in large orders for munitions, while Japan expanded sales of manufactured goods to Asian and other markets cut off from their usual European suppliers. Merchant shipping doubled in size and increased its income ten-fold as the European fleets were destroyed. Setbacks in the 1930s caused by the European postwar slump were only a spur to redouble efforts by diversifying heavy industry into the machine-making, metallurgical, and chemical sectors. Even the terrible 1923 Tokyo earthquake, which cost over 100,000 lives and billions of dollars, provided another stimulus due to the construction boom that followed. Riding the crest of this economic upsurge were the zaibatsu conglomerates — a dozen family-run combines, each involved in mining, manufacturing, marketing, shipping, and banking. These tightly controlled commercial pyramids were the true heirs to the old feudal structures. Japan's progress toward parliamentary democracy was halted in the 1930s by the growing nationalism being imposed on government by the generals and admirals. They proclaimed Japan's mission to bring progress to its backward Asian neighbors in language not so very different from that of the Europeans in Africa or the US in Latin America. After the Russian Revolution of 1917, the Soviet Union was regarded as a major threat to Japan's security, and the army felt it needed Manchuria and whatever other Chinese territory it could control as a buffer against Russian advances. In 1931 the Japanese occupied Manchuria. And then in 1937, with the popular support of ultra-right-wing groups, the army overrode parliamentary resistance in Tokyo and went to war against the Chinese Nationalists. By 1938, they held Nanking, Hankow, and Canton. Japanese expansionist policies were leading to direct confrontation with the West. Japan hoped that war in Europe would divert the Soviet Union from interference in East Asia, giving Japan a free hand both in China and, through its alliance with Germany, in French IndoChina after the defeat of France. The US responded to the Japanese invasion of IndoChina with a trade and fuel embargo, cutting off 90 percent of Japan's supplies. The result was the attack on the American fleet at Pearl Harbor (7 December 1941) and total war. 

Question: "What were a few of the tightly controlled commercial pyramids in Japan?"

Response: "Banking and shipping combines"
OPTIONS:
- no
- yes

A: no
Problem: Heat supplies the energy that causes motion. The deeper you go into toward the Earths core, the hotter it gets. At the core it is really hot. All that heat tries to rise toward the surface. In the Mantle, the rock is partially melted and is able to move. As it is heated, the material in the mantle moves toward the surface. As the mantle material rises, it cools. When it reaches the Earths crust, it is mostly stopped. A little of the material can break through the surface, but not all. Instead, it begins to move horizontally. The mantle material moves horizontally away from a mid-ocean ridge crest. Toward the surface, the mantle material starts to cool. As it cools it sinks back down into the mantle. These areas are where deep sea trench occur. The material sinks back down to the core. The system operates like a giant conveyor belt. The motion due to heating and cooling is called convection. 

Question: "Where does the heat deep in the Earth try to go?"

Answer: "Sea trench"

OPTIONS:
- no
- yes
Answer: no
Question:
You may wonder if there are other examples of static discharge. The answer is yes. Lightning is a form of static discharge. It is much more dramatic than what happens between you and the door knocker, but it is the same principle. You can see how it occurs in the following diagram and animation. You have no doubt seen lightning in a rainstorm. What does lighting have to do with static electricity? As it turns out, everything! During a rainstorm, clouds develop regions of different charges. This happens due to the movement of air molecules, water drops, and ice particles. The negative charges are concentrated at the base of the clouds. The positive charges are concentrated at the top. The negative charges repel electrons on the ground below. The ground then becomes positively charged. Over time the differences increase. Eventually the electrons are discharged. This is what we see as lightning. You can watch an awesome slow-motion lightning strike below.  After reading the above, is "Rain" the correct answer to the question "What do we see when electrons are discharged?"? OPTIONS:
- no
- yes

Answer:
no
Input: The digestive system is the body system that digests food. It digest food in two ways, mechanically and chemically. Both help in the process of turning food into nutrients. The digestive system also eliminates solid food waste. The major organs of the digestive system include the mouth, esophagus, stomach, and small and large in- testines. These organs all work together to help you gain energy from the food you eat. Digestion starts in the mouth. When food is swallowed, it travels through the esophagus to the stomach. In the stomach, digestion continues and a small amount of absorption of nutrients takes place. Most chemical digestion and nearly all absorption of nutrients take place in the small intestine. This organ consists of three parts: duodenum, jejunum, and ileum. The large intestine is the last stop in the digestive system. This is where water is absorbed. The food not digested is released as waste. 
"What does the digestive system do?" is "Digests food"?

OPTIONS:
- no
- yes
Output: yes
Earthquakes seemed to outline a special feature of earth's crust. Earthquakes let scientists know where the crust was moving. This led to the discovery that the Earths crust was broken up into regions, or plates. Earthquakes happen most often along these plate boundaries. This was evidence that continents can move. The movements of the plates are called plate tectonics. The Earths crust is divided into plates. There are about a dozen large plates and several small ones. Each plate is named for the continent or ocean basin it contains. Scientists know he plates are in motion. They now know the direction and speed of this motion . Plates dont move very fast. They move only a few centimeters a year. This is about the same rate fingernails grow. So you might wonder, what could cause this motion? What supplies the energy to cause this change? 

Question: "How many plates is the earth's crust divided into?"

OPTIONS:
- no
- yes

Answer: "More than 10 large ones"

Response:
yes