Lesson Plan #:AELP-SPA0008
Submited By: Katherine Beal
School or Affiliation: C.C. Meneley Elementary, Minden, NV
Endorsed: These lesson plans are the result of the work of the teachers who have attended the Columbia Education Center’s Summer Workshop. CEC is a consortium of teacher from 14 western states dedicated to improving the quality of education in the rural, western, United States, and particularly the quality of math and science Education. CEC uses Big Sky Telegraph as the hub of their telecommunications network that allows the participating teachers to stay in contact with their trainers and peers that they have met at the Workshops. Date: May 1994
Grade Level(s): 4, 5, 6, 7, 8, 9
Overview: One question frequently asked by students after viewing reports of Space Shuttle launches, has to do with a large world map used at NASA to display the path of the Shuttle as it orbits earth. On a flat map, the orbit path appears as a series of wavy lines. Students often ask why the Shuttle doesn’t just fly in a straight circle around the earth.
Teachers can use the following activities to help students visualize the relationship of motion, time and space as it relates to objects orbiting the earth.
Students will be able to:
Track the path of an orbiting object on a globe.
Plot the path of an orbiting object on a flat world map.
Explain that an object orbiting earth on a plane will produce a flight path which appears as wavy lines on the earth’s surface.
PART I – Orbit Flight Path (To be done with a partner)
Make an orbit plane by cutting a round hole in the center of a piece of oak tag board. The circumference of hole must be equal to the circumference of the classroom globe. A metal or washable plastic globe works best.
Draw lines on the orbital plane at twelve equal points around the circular hole. (A quick glance at a clock face will help students where to draw the lines.) The distance between each line represents the distance an orbiter will travel in the plane in one half hour. It takes the orbiter ninety minutes to circle the globe once.
Fit the orbital plane over the globe. Be sure the globe is tilting 23.5 degrees. Once correct orbit speed and altitude have been achieved, the balanced forces of inertia and gravitational pull will keep the orbiter circling in a plane around the earth. Engine thrust is no longer needed.
Imagine that an orbiter is moving along the plane in a clockwise direction. With a finger, trace the path of the orbiter as it circles the globe.
PART II – The Effect of the Earth’s Rotation on an Orbiter’s Flight Path
Recall that the earth is not stationary beneath the orbiting object. Rather, the earth is spinning toward the east on its axis at a rate of one latitude line (30 degrees) per hour.
Using a washable marker, (Transparency markers are best) make an X on the globe at any one of the orbital plane lines touching a line of longitude.
Now imagine that one half hour has passed. The orbiter has moved clockwise to the next orbital plane, but the earth has also moved in the last half hour. One partner should steady the orbital plane while the other partner rotates the globe toward the east, (counter clockwise) to the next longitude line. Mark the spot with an X and draw a line to connect this X with the next one. This is the orbital path.
Continue step three above ten more times, connecting the X’s. Your orbiter has made two complete revolutions around the earth. The path traveled by the orbiter has been on a straight plane. Remove the plane and observe the flight path on the globe. Because the earth is rotating at the same time the orbiter moves along its plane, the flight path appears wavy.
PART III – Plotting the Orbit on a Flat Map
Transfer the data from the globe onto a flat map by locating points of longitude and latitude. Connect the X’s. Note the wavy lines that appear. Emphasize again that the orbiter did not leave its plane.
Tying it all Together: NASA usually tracks the path of man-made satellites from a view point high above the orbiter, looking down at the earth. Because the earth is spinning on a tilted axis, objects orbiting the earth seem to have a wavy flight path. After completing these activities, students should understand that the combined movements of the earth and the orbiter result in what appears to be wavy flight paths.