Inquiry Physics Objectives

Links:

Content Standard III (State PASS Standard 1):
Forces and Motion

Topic:

9. Gravitation (state standard 1.2)
   Gravitation is a universal force that each mass exerts on any other mass. The strength of the gravitational attractive force between two masses is proportional to the masses and inversely proportional to the square of the distance between them.

Time Range:
16 weeks for Standard III

Suggested Teaching Strategies:

• This concept does not lend itself to experiments or physical demonstrations, but the story of how Western models of the solar system progressed is one of the most compelling in the history of science. Emphasize historical development of solar system conceptions from the Greek geocentric to the Copernican heliocentric, followed by Galilean evidence, Kepler’s Three Laws of Planetary Motion, Newton’s Universal Gravitation equation, Cavendish’s measurement of the Universal Gravitation Constant, and Einstein’s reconception of gravity as a warp in space-time.
• One demo of Kepler's Second Law (and conservation of angular momentum) is to take a string about a meter long and tie one end to a key and the other to the handle of a mug. Put the string over the edge of a meterstick with the mug close to the meterstick. Hold the stick mid-air with one hand and hold the key with the other. When the key is released it will whip around the stick and prevent the mug from hitting the floor.

Aligned Resources:

• Inquiry Physics Investigation 11 – Universal Gravitation, including crossword puzzle and Reading: The Law of Universal Gravitation
• NASA's J-Track Online Orbital Tracking
• Software packages:
  • Gravity – simple solar system simulator
  • STSPLUS – orbital tracking software for satellites, shuttles, space station
  • Epicycle – simulates use of epicycles to explain retrograde planetary motion in geocentric systems
• Videotape: The Day the Universe Changed with James Burke – Infinitely Reasonable
• NASA warped space simulation movies on Inquiry Physics CD-ROM to illustrate Einstein’s reconception
• Seasons and Phases of the Moon Powerpoint Presentation from Inquiry Physics

Revision Date:
June 2004