Chapter 36 The Special Theory of Relativity

Introduction Our goals –Better appreciate some underlying assumptions of CM –Get new understanding and insight into physical reality –Appreciate some practical applications and impacts on thinking of SR –Better appreciate science as a process in contrast to a body of knowledge

Introduction (cont’d) Our plan –Look at the Historical/Intellectual context –Identify the assumptions of Special Relativity –Draw our first conclusions Time dilation Length contraction –Look deeper: The relativity of simultaneity –Introduce space-time diagrams (part 1)

Introduction (cont’d) Our plan (cont’d) –Introduce and use the Lorentz transformation –Introduce relativistic Energy and Momentum –Continue with other topics depending on interest and time

Historical/Intellectual Context Knowing (constructed knowledge) The clash of CM, E&M –Galilean Relativity Absolute space  relative space, absolute time Absolute time and space intervals –The absolute velocity of EM Specific difficulties seen at the time –Light in box, catching up with light, etc. –No ether

Assumptions of SR The Relativity Principle The Constancy of the Speed of Light in a vacuum (Hence the need to reformulate physics)

Our first conclusions Time dilation –Proof –Evidence (planes, satellites, muons) Length contraction –Proof (built on time dilation) –Evidence (muons, space travel plans) – Question Hence the connection between space and time (seen in electricity/magnetism)

Deeper: Relativity of Simultaneity Cup and Arrow thought experiment/demo Classic train/embankment example (1917) –Both perspectives presented and compared Quantitative result (state) Space-time diagrams (part 1) –The experiment from the embankment –Comment on the relation of frames

The Lorentz Transformation What the Galilean and Lorentz transformations describe Mathematically, the Galilean and Lorentz transformations Results –The addition of velocities –Time dilation –Length contraction –Lack of simultaneity

Completing Mechanics Relativistic momentum –“relativistic mass”??? Relativistic kinetic energy & total energy –mass-energy relation Further topics, time permitting –make your suggestions

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