What's Gravity Got To Do With It?

Transcription

1 Monday, December 16 What's Gravity Got To Do With It? By Erin Horner When you woke up this morning did you fly up to the ceiling? Of course not! When you woke up this morning you put both feet on the floor and stood up. Then, you walked out of your room. Why didn't you fly up to the sky? You stayed on the ground thanks to gravity. Gravity is defined as "the force by which all objects in the universe are attracted to each other." This means that gravity pulls things towards the center of the Earth. Gravity keeps our feet on the floor because it is pulling us toward Earth's core. Gravity is the invisible force that keeps all things, cars and kids included, from flying up into outer space! All of the planets in the solar system have gravity. The larger the planet, the more gravity it has. This means that large planets like Jupiter have a lot of gravity. Pretend that you weigh 85 pounds on Earth. On Jupiter you would weigh over 200 pounds! This is because Jupiter has more gravity than Earth. On the other hand, smaller planets have less gravity. On Mercury, your 85 pound body would only weigh 32 pounds. This is because Mercury has less gravity then Earth. Gravity is also what makes the planets round. The force of gravity pulls equally in all directions. This constant equal force is what gives the planets their round shapes. The more gravity a planet has, the rounder it will be. This explains why some small moons are shaped like ovals. They do not have enough gravity to make them perfectly round. Everything in outer space has gravity because everything everywhere has gravity. Gravity is less in space as distance from a planet increases. People have gravity. Buildings have gravity. Anything with mass has gravity. These things don't have nearly much gravity as planets do, though. They are all too small. This is probably a good thing. We would all look pretty silly if lots of gravity made us constantly stick to one another! What's Gravity Got To Do With It? 1. What has gravity? 2. What can the reader conclude after reading this passage? A. Only planets have gravity. B. Only large planets have gravity. C. A small planet will have less gravity then a large one. D. Earth has the most gravity.

2 Monday, December The author probably wrote this passage to. A. Demonstrate how to weigh yourself on Mercury. B. Persuade you to fly out of your bed. C. Describe the solar system. D. Inform you about the force of gravity. 4. What would most likely happen if there was no gravity? A. Buildings would crumble. B. Our feet would stick to the Earth. C. We would all weigh more. D. We would float up, up, and away. Imagine that you could live for one day with no gravity. What do you think it would be like? What would you do?

3 Tuesday, December 17 Earth's Next Door Neighbor By Erin Horner Who is your next door neighbor? Do you and your neighbor have a lot in common? Our planet has a neighbor. Earth's neighbor is the planet Mars. These neighbors have a lot in common. Their landforms are very similar. Both Mars and Earth have canyons and valleys. They both have mountains, too. Mars's mountains are a lot taller, though! Both of these planets also have volcanoes. While they are a lot alike, Mars and Earth are also very different. Mars is smaller and much colder than our planet. The average temperature on Mars is 80 degrees below zero! That is a lot colder than the North Pole! Mars also has two moons. Earth only has one. Our moon is round. Mars's moons look like lumpy potatoes. They are shaped like ovals and full of craters. These moons are also very small. No person has ever set foot on Mars. But who knows? Someday, scientists might make it possible to explore this space neighbor in person. Then we could really learn about all that these "next door neighbor" planets have in common. Earth's Next Door Neighbor 1. Name one way that Mars and Earth are different. 2. After reading this passage the reader can conclude that. A. Mars is just like Earth. B. Many animals live on Mars. C. People could live on Mars. D. A person could not live on the planet Mars. 3. How is this passage organized? A. It gives a series of steps in a process. B. It states a cause and then gives effects. C. It makes a statement and then gives the reason it is true. D. It tells how things are alike and different. 4. The author probably wrote this passage to. A. Persuade you to become an astronaut B. Describe the similarities and differences of Earth and Mars C. Inform you about space travel D. Demonstrate the orbit of Mars

4 Wednesday, December 18 Phases of the Moon By Patti Hutchison Was there a full moon last night? Some people believe that a full moon affects people's behavior. Whether that is true or not, the moon does go through phases. What causes the moon to appear differently throughout the month? You know that the moon does not give off its own light. When we see the moon shining at night, we are actually seeing a reflection of the Sun's light. The part of the moon that we see shining (lunar phase) depends on the positions of the sun, moon, and the earth. When the moon is between the earth and the sun, we can't see it. The sunlit side of the moon is facing away from us. The dark side is facing toward us. This phase is called the new moon. As the moon moves along its orbit, the amount of reflected light we see increases. This is called waxing. At first, there is a waxing crescent. The moon looks like a fingernail in the sky. We only see a slice of it. When it looks like half the moon is lighted, it is called the first quarter. Sounds confusing, doesn't it? The quarter moon doesn't refer to the shape of the moon. It is a point of time in the lunar month. There are four main phases to the lunar cycle. Four parts- four quarters. For each of these four phases, the moon has orbited one quarter of the way around the earth. This is why it is called a quarter moon when it really looks like a half moon. As the orbit continues, we begin to see more than half of the lighted side of the moon. This is called a waxing gibbous moon. As the lunar month goes on, the moon continues on its path. It comes to a position where the earth is between it and the sun. This time the sunlit side is facing us. We call it a full moon. Once the full moon is reached, we start to see less and less of the sunlit side. It looks like tiny slices are being taken off. This is called waning. When we still see more than half the moon shining, it is called a waning gibbous moon. Soon, the moon reaches its third quarter phase. Again, it looks like only half the moon is lighted. We are seeing half the sunlit side. As we begin to see less and less of the sunlit portion, the moon is becoming a waning crescent. Soon it will "disappear" once again and become a new moon. There are four lunar phases: new moon, first quarter, full moon, and last quarter. It takes the moon about 29.5 days to complete this cycle. This is called a lunar month. Ancient civilizations set their calendars by the phases of the moon. Many calendars, and even some clocks, keep track of the moon's phases yet today. Phases of the Moon 1. Why can't we see the moon during the new moon phase?

5 Wednesday, December As the amount of sunlight we see reflected increases, it is called: A. waning B. last quarter C. waxing 3. Name the four phases of the lunar cycle. 4. After the full moon, we see less and less of the sunlit side. This is called: A. waxing B. waning C. gibbous 5. How long is a lunar month? 6. When the moon looks like a half moon, it is in its: A. full moon phase B. first or third quarter phase C. new moon phase

6 Thursday, December 19 Water on the Moon! By Cindy Grigg We used to think the moon was as dry as dust. But NASA has found that deep inside the Cabeus crater, there is water in the form of ice. How much water is there? Enough to fill 1,500 big swimming pools! The Cabeus crater is near the moon's south pole. The crater is so deep that light from the sun never reaches the bottom of it. Scientists estimate that the crater holds a billion gallons of frozen water! Why is this important? Water is heavy, and it would be expensive for spaceships to carry enough of it to last for a long space journey. But if there's water on the moon, spaceships could stop there to fill up with it. Not only is water needed by space travelers to drink, but the water could be used in other ways. Water could be separated into its parts. Oxygen could be used for breathing. Hydrogen might be used as fuel for the spaceship. If there is hidden water on the moon, maybe it exists on other planets. Water refilling stations might be set up on them. Of course, sending people on long trips into space can't happen in the near future. But the idea of water on the moon has many scientists excited about the possibilities. Water on the Moon! 1. We used to think the moon was as dry as dust. This sentence is an example of. A. a simile B. a metaphor C. alliteration D. irony 2. Scientists estimate there are gallons of frozen water. 3. What are some possible uses for the water on the moon? A. drinking B. breathing C. fuel D. all of the above E. none of the above

7 Thursday, December The story says that water ice was found in one crater on the moon. What inference or guess could logically be made from this? A. If there is ice in one crater, there may be more in other craters on the moon. B. The water could be used in other ways. C. Spaceships would have to wait months to get water from the ice. D. none of the above What is NASA? When was it first formed? What is its purpose? Do research and share your findings with your class.

8 Friday, December 20 Is Pluto a Planet? By Patti Hutchison Caption: Size comparison of Earth and its moon to Pluto and its moon, Charon It is; it isn't. It is, but with some restrictions. No, it isn't. Yes, it is, sort of. These are the arguments about poor Pluto. Is it a planet, or isn't it? Pluto was once thought of as the smallest planet. It was also known as the coldest planet since it is the farthest from the sun. It was discovered in Since then, scientists have had trouble deciding if it really is a planet or not. In 2006, the International Astronomical Union (IAU) made some new "planetary rules." According to the new rules, a true planet must do three things. First, it must orbit the sun. Secondly, it must be big enough for gravity to make it into a round ball. And lastly, it must have cleared out its orbital neighborhood. There can't be any "junk" floating around it. Let's look at these criteria in terms of Pluto. It does follow rule number one. It orbits the sun. How about rule number two? Yes, it follows rule number two. It is a round ball. Rule number three is where Pluto gets into trouble. It's "neighborhood" is full of "junk." The Kuiper Belt is close by. This is a disc-shaped belt of icy particles. Ceres, the largest asteroid known so far, also is close to Pluto. So, just what is Pluto, anyway? The IAU defines it as a dwarf planet. This means that it meets rules one and two. But it has not cleared the neighborhood around its orbit. It is also not a satellite, which meets rule number four for a dwarf planet. No matter what it is called, Pluto is still out there. No spacecraft has yet landed on Pluto, but we do know some things about it. It was discovered by an American astronomer whose name was Clyde Tombaugh. No, it was not named for the Disney character. Pluto gets its name from the Roman god of the underworld. Pluto travels in a very elliptical orbit. From 1979 to 1999, Pluto was actually closer to the sun than Neptune. But this will not happen again for another 230 years. The closest Pluto gets to the sun is about 4.7 billion kilometers. At the farthest point in its orbit, it is about 7.4 billion kilometers from the sun. It takes Pluto 248 Earth years to make one complete orbit. Pluto also has a slow rate of rotation. Its day is equal to about six Earth days. If you're going to Pluto, you'd better take your warm jacket. The average temperature there is -215 degrees Celsius. Scientists think it is the largest object in the icy Kuiper Belt. From Pluto, the sun looks like a bright star in the sky. Pluto has no air to breathe. Because Pluto is so far away, it is hard to see, even with very powerful telescopes. Scientists are not sure what its surface looks like. They believe it is covered with frozen nitrogen, methane, and carbon dioxide. Some areas are very white like snow; others are very dark. Pluto has very weak gravity. If you weigh 100 pounds on Earth, you would only weigh eight pounds on Pluto! Pluto has four known moons. The largest one, Charon, is more than half the size of Pluto. Charon is covered with ice. The two bodies are in mutually synchronous orbit. This means that they move at the same rate. They always keep the same side facing each other. If you were to look at Charon from Pluto, it would not appear to rise or set. It would seem like it was just floating in space. The same would be true if you stood on Charon and looked at Pluto.

9 Friday, December 20 In 2006, NASA launched a spacecraft to Pluto called New Horizons. It will reach Pluto in Its job is to study Pluto and the Kuiper Belt. Scientists think this mission will give us clues about how the solar system was formed. Is Pluto a Planet? 1. What does IAU stand for? 2. Why is Pluto considered to be a dwarf planet? 3. A disk-shaped belt of icy particles in Pluto's orbital neighborhood is called: A. Charon B. the Kuiper Belt C. Ceres 4. Sometimes Pluto is closer to the sun than Neptune. A. true B. false 5. How many Earth years does it take Pluto to orbit the sun? A. 6 B. 248 C. 4.7 billion 6. If you visited Pluto, you would weigh more there than you do on Earth. A. false B. true