Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Example Input: Context: A physical change in matter is a change in one or more of matters physical properties. Glass breaking is just one example of a physical change. Some other examples are shown in Figure 3.16 and in the video below. In each example, matter may look different after the change occurs, but its still the same substance with the same chemical properties. For example, smaller pieces of wood have the ability to burn just as larger logs do. MEDIA Click image to the left or use the URL below. URL: Because the type of matter remains the same with physical changes, the changes are often easy to undo. For example, braided hair can be unbraided again. Melted chocolate can be put in a fridge to re-harden. Dissolving salt in water is also a physical change. How do you think you could undo it? Did you ever make a "volcano," like the one in Figure 3.17, using baking soda and vinegar? What happens when the two substances combine? They produce an eruption of foamy bubbles. This happens because of a chemical change. A chemical change occurs when matter changes chemically into an entirely different substance with different chemical properties. When vinegar and baking soda combine, they form carbon dioxide, a gas that causes the bubbles. Its the same gas that gives soft drinks their fizz. Not all chemical changes are as dramatic as this "volcano." Some are slower and less obvious. Figure 3.18 and the video below show other examples of chemical changes. MEDIA Click image to the left or use the URL below. URL: How can you tell whether a chemical change has occurred? Often, there are clues. Several are demonstrated in Figures 3.17 and 3.18 and in the video below. MEDIA Click image to the left or use the URL below. URL: To decide whether a chemical change has occurred, look for these signs: Gas bubbles are released. (Example: Baking soda and vinegar mix and produce bubbles.) Something changes color. (Example: Leaves turn from green to other colors.) An odor is produced. (Example: Logs burn and smell smoky.) A solid comes out of a solution. (Example: Eggs cook and a white solid comes out of the clear liquid part of the egg.) Because chemical changes produce new substances, they often cannot be undone. For example, you cant change a fried egg back to a raw egg. Some chemical changes can be reversed, but only by other chemical changes. For example, to undo the tarnish on copper pennies, you can place them in vinegar. The acid in the vinegar reacts with the tarnish. This is a chemical change that makes the pennies bright and shiny again. You can try this yourself at home to see how well it works. If you build a campfire, like the one in Figure 3.19, 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 thats 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, but in fact, 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. 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. The law states that matter cannot be created or destroyed. Even when matter goes through physical or chemical changes, the total mass of matter always remains the same. (In the chapter Nuclear Chemistry, you will learn about nuclear reactions, in which mass is converted into energy. But other than that, the law of conservation of mass holds 
 Question: After a physical change, matter may
Example Output: look different.

Example Input: Context: In The Future, a beautiful astronomatrix named Barbarella (Jane Fonda) floats through the galaxy in her spaceship, the Alpha-7. Suddenly she receives an urgent call on her monitor from none other than the President of Earth (Claude Dauphin). He informs her that a young scientist named Durand-Durand went missing sometime during a mission to the North Star and is believed to have landed somewhere in the Tau Ceti star system. Not much is known about this region of space-- the President worries that Durand's invention, the positronic ray, may fall into the hands of a primitive culture; beings who might seek to use this technology as a weapon and launch an intergalactic war. Since the Earth, free of all conflict for centuries, lacks military and police personnel, the President tasks Barbarella with a mission to find the scientist. He teleports her some weapons and a device that will signal the presence of Durand-Durand. The latter has a "tonguebox" incorporated in its design which can translate any language.Barbarella spends most of the journey to Tau Ceti in suspended animation. She awakens just in time to lose control of her spacecraft and crash land on Planet 16, which her spaceship informs her contains an atmosphere similar to Earth's. She changes into a new outfit to explore the arctic terrain. The first humanoids she meets are a pair of twin girls-- they jabber to her excitedly in a language she can't understand. Before she can adjust her tonguebox, one of them knocks Barbarella unconscious with a piece of ice. The girls then pull the dazed explorer along in their sled, which is attached to a manta ray-like creature that glides across the ice.The girls arrive with Barbarella at the wreck of another craft where several other sets of twin children are sheltered and indigo-blue bunny rabbits abound. Barbarella recognizes the wreck as the Alpha-1, former spaceship of Durand-Durand. The children tie Barbarella to a post and bring out several mechanical dolls that walk towards her. It soon becomes apparent that the dolls all have sharp metal teeth and hinged jaws. They bite Barbarella while the children giggle gleefully, amused by their game.Suddenly a man appears with several armored guards. He cracks a whip and captures the children in a net, then unties Barbarella. Once she gets her tonguebox working, she's able to understand him when he explains that he is a Catchman named Mark Hand (Ugo Tognazzi) and that all children are sent away to the forests of Weir "until they've reached a serviceable age," at which point he captures them and brings them back to civilization. He offers Barbarella a ride back to her spaceship. When she asks how she can repay him, he tells her that he'd like to make love to her. Back on Earth, when people want to bond, erotically, they each take an exultation transference pill and press their palms against one another's. Barbarella is prepared to do this with the Catchman, but he's not interested in all that, he tells Barbarella that he wants to have sex on the bed in his snowship. She reluctantly agrees to do it the old-fashioned way, but soon discovers that she finds the experience quite enjoyable. The Catchman gives her a fur and repairs her spaceship, only when she tries to fly off, the ship's computer informs her that it's been repaired in reverse. She crashes back into the planet and quickly activates the ship's terra-screws so that she can tunnel through the planet's core.She surfaces in the Labyrinth, amongst strange creatures including an "ornithanthrope," or angel, named Pygar (John Phillip Law), who was blinded in the city of Sogo. Pygar takes Barbarella to visit Professor Ping (Marcel Marceau) who explains that Pygar is aerodynamically sound, but lacks the morale to fly. Pygar, Professor Ping and all of the other unfortunates who roam the Labyrinth were imprisoned there by order of the Great Tyrant. They are not evil enough to be allowed to live in Sogo, the City of Night. Pygar takes Barbarella to his nest where they have sex. This restores Pygar's will to fly and Barbarella 
 Question: Who offered to repair the ship?
Example Output: the catchman

Example Input: Context: Seismic waves are measured on a seismograph. Seismographs contain a lot of information, and not just about earthquakes. A seismograph is a machine that records seismic waves. In the past, seismographs produced a seismogram. A seismogram is a paper record of the seismic waves the seismograph received. Seismographs have a weighted pen suspended from a stationary frame. A drum of paper is attached to the ground. As the ground shakes in an earthquake, the pen remains stationary but the drum moves beneath it. This creates the squiggly lines that make up a seismogram (Figure 7.33). Modern seismographs record ground motions using electronic motion detectors. The data are recorded digitally on a computer. Seismograms contain a lot of information about an earthquake: its strength, length and distance. Wave height used to determine the magnitude of the earthquake. The seismogram shows the different arrival times of the seismic waves (Figure 7.34). The first waves are P-waves since they are the fastest. S-waves come in next and are usually larger than P-waves. The surface waves arrive just after the S-waves. If the earthquake has a shallow focus, the surface waves are the largest ones recorded. A seismogram may record P-waves and surface waves, but not S-waves. This means that it was located more than halfway around the Earth from the earthquake. The reason is that Earths outer core is liquid. S-waves cannot travel One seismogram indicates the distance to the epicenter. This is determined by the P-and S-wave arrival times. If a quake is near the seismograph, the S-waves arrive shortly after the P-waves. If a quake is far from the seismograph, the P-waves arrive long before the S-waves. The longer the time is between the P-and S-wave arrivals, the further away the earthquake was from the seismograph. First, seismologists calculate the arrival time difference. Then they know the distance to the epicenter from that seismograph. Next, the seismologists try to determine the location of the earthquake epicenter. To do this they need the distances to the epicenter from at least three seismographs. Lets say that they know that an earthquakes epicenter is 50 kilometers from Kansas City. They draw a circle with a 50 km radius around that seismic station. They do this twice more around two different seismic stations. The three circles intersect at a single point. This is the earthquakes epicenter (Figure 7.35). The ways seismologists measure an earthquake have changed over the decades. Initially, they could only measure what people felt and saw, the intensity. Now they can measure the energy released during the quake, the magnitude. Early in the 20th century, earthquakes were described in terms of what people felt and the damage that was done to buildings. The Mercalli Intensity Scale describes earthquake intensity. There are many problems with the Mercalli scale. The damage from an earthquake is affected by many things. Different people experience an earthquake differently. Using this scale, comparisons between earthquakes were difficult to make. A new scale was needed. Charles Richter developed the Richter magnitude scale in 1935. The Richter scale measures the magnitude of an earthquakes largest jolt of energy. This is determined by using the height of the waves recorded on a seismograph. Richter scale magnitudes jump from one level to the next. The height of the largest wave increases 10 times with each level. So the height of the largest seismic wave of a magnitude 5 quake is 10 times that of a magnitude 4 quake. A magnitude 5 is 100 times that of a magnitude 3 quake. With each level, thirty times more energy is released. A difference of two levels on the Richter scale equals 900 times more released energy. The Richter scale has limitations. A single sharp jolt measures higher on the Richter scale than a very long intense earthquake. Yet this is misleading because the longer quake releases more energy. Earthquakes that release more energy are likely to do more damage. As a result, another scale was needed. The moment magnitude scale is the favored method of measuring earthquake magnitudes. It measures the total 
 Question: paper record of seismic waves produced by a seismograph
Example Output:
seismogram