The Flat Sphere
Print The Flat Sphere Reading Comprehension
||edHelper's suggested reading level:
||grades 8 to 9
||Flesch-Kincaid grade level:
||equally-spaced, mercator, polyconic, stretched-out, grid-like, distortion, unequal, plotting, conic, cartographers, projection, sphere, representation, cylindrical, mathematical, cone-shaped
The Flat Sphere
By Trista L. Pollard
1 It sits on the counter by the window peering out into the world. It comes to life when the names of countries, explorers, and oceans are thrown around the room. It's your trusty classroom globe! Students throughout the years have seen a globe or two by their classroom windows. We take this colorful sphere for granted. However, have you ever wondered how scientists produce such an accurate model of our planet?
2 Cartographers are the earth scientists responsible for producing globes and maps of Earth. For centuries, scientists have made models and pictures of our planet. Today's cartographers use different methods for collecting information about the Earth's surface. Technology in the form of satellites and airplane computers has allowed scientists to collect images of Earth from space and high altitudes. This is done through remote sensing. By using remote sensing, scientists can take images of the Earth's surface from space and analyze those images. In addition to remote sensing, cartographers also conduct field surveys. Field surveys allow scientists to measure specific areas on Earth that need to be mapped. They walk or drive through these areas, collecting measurements and plotting those measurements on maps. Surveyors then use these measurements to make measurement estimates for areas between the surveyed points. Once all of the information is collected, cartographers produce globes and maps of our planet.
3 Speaking of globes, can you imagine how hard it would be if that was the only representation of our planet we could use? It would be very hard to store globes in our cars as we travel. Well, cartographers have found ways to transfer the images from a globe to a flat map. Scientists accomplish this goal by using map projections. Imagine having a transparent globe with a flashlight inside. It would be very easy to wrap the globe with paper and trace its images onto the paper. As you may have guessed, it is not that simple. Cartographers use mathematical formulas to make map projections. Three basic map projections are used- cylindrical, conic, and azimuthal. A fourth projection, interrupted, is not used as often as the previous three. Each map projection has its advantages and disadvantages.
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