Unit IX: Relativity

Introduction

Einstein had a tremendous impact on modern physics. He proposed, which we know now to be true, that all measurements of space and time depend on relative motion. His special and general theories of relativity are so removed from our daily lives (since much of them are in spaceships) that understanding the concepts can be quite difficult. At this level, just becoming familiar with the concepts will be evidence of success. The unit is broken into two sections and should take a week. Intended Learning Outcomes
 
General Instructional Objectives (and corresponding Specific Learning Outcomes) Unit Content
Knows terms

Understands the meaning of terms

simultaneity, time dilation, length contraction, reference frame, space-time, mass-energy equivalence, gravitational red shift, geodesic
Understands scientific concepts Postulated of the special theory of relativity, length contraction, mass-energy equivalence, principle of equivalence
Knows all laboratory procedures

Prepares a plan for an experiment

Participates in classroom activities

Respects the scientific process

Displays a scientific attitude

Demonstrates skills in laboratory work

All content

Instructional Foci

Homework, quizzes, class discussion, questions for thought from the Flying Circus of Physics Teaching Strategies Give it your best! Begin with a discussion of Albert Einstein and his contributions to science—physics in particular. Then discuss how motion is relative to your frame of reference. Discuss Einstein’s postulates of the special theory of relativity, including simultaneity, space and time, and time dilation. The twin trip is a good way to approach these subjects, including length contraction. Then for the famous mass-energy equivalence, E = mc2. This is the concept that everything has energy of being if it has a mass. This energy of being is called rest energy.

Underlying Einstein’s general theory of relativity is the idea that gravity and acceleration cannot be distinguished from one another. Topics such as the principle of equivalence and the bending of light by gravity should be discussed. The gravitational red shift basically says that the stronger a gravitational field, the slower a clock runs. Therefore, a clock a the surface of the earth runs slower than a clock at the surface of the moon. Gravity and space should then be discussed. To conclude, a comparison of Newtonian and Einsteinian gravitation should be discussed.

Special Notes 1. Relativity is completely conceptual, which is good. However, it has few, if any, examples in the real world. The teacher must rely on clear lectures and lengthy discussion to achieve optimal understanding by the students. return to main page
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