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He takes a globe down from the shelf and gets a transparency illustrating the sun and the planets in relative size to each other from his file cabinet. The students are told to read the chapter, and he spends the first day of the unit identifying the parts of the solar system and the names of the planets. He lists the planets on the board in order of their distance from the sun and points out that Mercury, Venus, Earth, and Mars were quite small and close to the sun, so they’re called the inner planets, and that Saturn, Jupiter, Uranus, Neptune, and Pluto are called the outer planets. He tells the students that Venus is called the Earth's twin because its size is about the same as the earth, but that no could live on Venus because it was too hot. He then showed the students the transparency identifying the inner and outer planets. On the second day, Steve begins class by saying, “All right everyone, what have we learned about the solar system so far?” “Sun and planets,” Wendy volunteered. “It has our sun and the planets,” Steve affirms. “Who can name the planets? . . . Anyone. Go ahead, Laquita.” “. . . Mercury,” Laquita begins, “. . . Venus, Earth, . . . Mars, . . . Saturn . . . “ ”That’s good, David, but you missed one. Someone help him out.” “. . . Jupiter,” Traci puts in. “Good Traci,” Steve smiles. “Remember when we listed the names of the planets on the board, and I said that we needed to know all of the them in order. Look back in your notes if you’re not sure. “Jupiter and then Saturn,” Steve continues. “Now, what’s next?” “Uranus,” several of the students responds in unison. “Good, and next?” “Neptune,” the class answers. “Excellent! And finally?” “Pluto!” the class responds, warming to the process. “Very good everyone, and what else is part of our solar system?” “Asteroids,” Paula adds. “Yes! Very good! There is an asteroid belt between Mars and Jupiter. Some scientists think that it is the remains of a giant planet. “The asteroids are like a bunch of small planets,” he goes on. “They vary in size from about the size of a small moon to small pieces of gravel. “They think that perhaps the planet got too close to another planet and maybe even collided. The asteroids are what remain. They are in orbit around the sun, just like the planets are. “What else is part of our solar system?” “. . .” “. . . No one. Well, have any of you hear of Halley’s comet? . . . Good, I see several of you nodding. Okay, Halley’s comet is probably the most famous of all the comets, but it is just one of them. . . . Comets go around the sun just as the planets do. They are fairly small objects of stone, minerals and ice that orbit the sun in elliptical, oblong orbits. “Mr. Grant?” Natasha calls out, raising her hand. “Yes, Natasha.” “Are the comets in between the planets, like the asteroids are?” “Well, not exactly. They have different kinds of orbits. “Now today, we want to talk some more about Pluto. We know that it is the smallest and the farthest away from the sun. Many believe that its origin is different from the other planets. Now, the reason they think that is because its orbital plane is different from that of the other planets. “By that I mean the plane that all the planets revolve around the sun in,” Steve continues. “Everyone, take a look on page 284 of your books. It shows the orbital planes of the planets. “Now, Pluto’s orbital plane is different,” he repeats, “so they think it was different. Like maybe it was captured from out in space and became a part of the solar system that way. “So remember, everyone, and this should be in your notes. Pluto’s origin is different from the other planets. “Yes, Jack,” Steve nods acknowledging Jack’s raised hand. “What’s the orbit got to do with the way the planets were made?” “Very good question Jack,” Steve smiles. “What’s the orbit got to do with the planets? Let's look at the transparency.” Steve then displays a transparency showing the sun throwing off globs of gases into space and says, “What does this transparency show us. Jack?” “. . . Globs being thrown off from the sun.” “That’s right. You see, they think that the planets were once part of the sun, and the sun sort of ‘threw’ them off,” Steve waves in a throwing motion. “Then they gradually cooled off, solidified and became the planets. So, they were all originally made out of what?” “. . .” “What is the sun made out of?” “Gases,” the class responds. “What did he say about orbits?” Benjie whispers to Janet as he looked up from writing his notes. “I didn’t get it.” “I’m not sure. He said the planets came off the sun, I think.” “How?” “I don’t know. Just came off I guess.” “Yes. Good. So, what were the planets to start with?” Steve goes on. “Gases.” “Yes. Excellent. So, the planets cooled down from the gases and formed the planets as we know them now.” “Any other questions? . . . Okay. . . . Benjie, do you have a question?” Steve asks seeing a confused look on Benjie’s face. . . . Okay? . . . Good,” he gestures as Benjie nodded no. “So, let’s review what we've covered, so far. What do we know about Pluto?” “It’s far from the sun,” Nancy volunteers. “Good, Nancy. What else?” “Small,” Shelley adds. “Okay. And what else?” “It was made different.” “Yes! Excellent Shelley. That's what we are looking for. Pluto's origin is different form the other planets.” “Now as a homework assignment, I want you to use your books and fill out the following chart. . . . Here, I have made some outlines for you,” and he then hands the students the chart that appears as follows:
Discussion Questions
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