Special Relativity

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Special Relativity

• Nolan Lee
• Middle Years Applied Skills 9
• Block C

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Table of Contents

• Special Relativity Background Information
• The Fundamental Properties of the Universe -
  (Part 1 of Introduction)
• Characteristics of Light - (Part 2 of
  Introduction)
• Special Relativity What It Is
• The Two Postulates of Relativity
• Skewing, Length Contraction, Time Dilation and
  Time Intervals
• Conclusion
• Works Cited
• Activity

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Section 1 Special Relativity Background
Information

• Special relativity theory first put forward by
  Einstein in 1905
• Created to take care of some theoretical concerns
  about classical electrodynamics, but resulted in
  the modification of some of the laws of mechanics
• Theory explores structure of space and time and
  effect on motion, forces and other dynamical
  phenomena
• 1908, Hermann Minkowski revised theory -basing it
  on postulated geometric properties of space and
  time

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The Fundamental Properties of the Universe (Part
1 of Introduction)

• SPACE
• 3-D, allows objects to have length, width, and
  depth
• TIME
• 4th dimension, essential for physical existence
• Space and time woven together - because they work
  together without one, the other would be useless
• Mutual dependence called space-time continuum
• MATTER
• Most fundamental definition ? anything that takes
  up space
• Made up of millions of billions of atoms
• Atoms made of Protons, Neutrons, Electrons
• Number of particles in an atom very important
  i.e. Number of protons an atom has determines
  atoms place on periodic table of elements
• MOTION Anything thats in the act of changing
  its location in space
• Mass and Energy
• Mass in physics ? measure of how much matter an
  object has / body contains
• Mass is independent of position in space

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The Fundamental Properties of the Universe (Part
1 of Intro) Pg. 2

• Energy measure is systems ability to perform
  work
• Exists in many forms ? potential, kinetic...
• Law of conservation of energy ? energy cant be
  created or destroyed only changed

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Characteristics of Light (Part 2 of Introduction)

• Light ? form of energy
• Exhibits characteristics of waves and energy ?
  duality (both present at same time)
• Particle from light ? photon ? known as
  electromagnetic radiation
• Electrons orbiting nucleus of the atom move away,
  and as they fall back towards the nucleus, energy
  in form of light emitted
• Light created by oscillating charge charge
  consists of oscillating electric and magnetic
  field

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Characteristics of Light (Part 2 of Intro) Pg. 2

• As light travels in a straight line, it can
  refract or reflect (can be sucked in if it comes
  within event horizon of a black hole)
• Reflects in a straight line across shiny and
  smooth surfaces
• Refraction occurs when the light bends as it
  passes though an object (like prism or droplet(s)
  of water)
• Speed of light / speed of info / speed of
  electromagnetic radiation 1.86 105 miles/sec.
  (in vacuum)

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Special Relativity What It Is

• Frames of Reference ? what special relativity is
  based on
• Frame of reference ? where a person/an observer
  happens to be
• No such thing as an absolute frame of reference ?
  no place in universe that is totally stationary
• Everyone and everything - ALWAYS moving in time
  AND space
• Eg. If you jump people lying on the ground
  could view YOU as being at rest, and THEMSELVES
  as being in motion

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The Two Postulates of Relativity

• The first postulate of Special Relativity The
  laws of physics hold true for all frames of
  reference.
• (How Special Relativity Works 2.0)
• Eg. Consider a meter stick and a brick-whether
  you measure the brick on an airplane, or on the
  ground, the outcome will be the same. If we
  measure the time it takes to complete 15 pendulum
  swings (starting at the same distance from
  resting point) in both locations, the results
  are also the same. However, if we are able to
  measure the brick and the time of the pendulum
  swings from the ground as they fly past on an
  airplane, then compared these results to the same
  measurements made on the ground the results
  will then be different
• Above is true because laws of physics same for
  all frames of reference ? they only do not hold
  true when comparing different frames of reference

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The Two Postulates of Relativity (Page 2)

• The second postulate of relativity The speed of
  light is measured as constant in all frames of
  reference.
• (How Special Relativity Works 2.0)
• Means that no matter how fast you are going, the
  speed of light would measure the same
• Nothing can go faster than light Eg. A car
  moves at 60 km/hr. and a stick is thrown from the
  car at 10 km./hr. (in the same direction) ? If
  you are standing on the street, then the stick is
  moving at 70 km/hr. (6010). However if the same
  car turns its headlights on, the light moves
  only at the speed of light, not at the speed of
  light 60 km/hr.
• Light speed is constant and speed distance
  divided by time ? so if light speed does not
  change even if it is launched from a moving
  object - either distance or time must be skewed
  (it turns out, both are skewed)

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Skewing, Length Contraction, Time Dilation and
Time Intervals

• Skewing when an object with mass is in motion ?
  measured length shrinks in direction of motion
  if object reaches speed of light, measured length
  shrinks to nothing (from bystanders frame of
  reference) ? called length contraction
• Eg. An airplane seems shorter than it actually
  is, from stationary frame of reference

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Skewing, Length Contraction, Time Dilation and
Time Intervals (Page 2)

• Time Dilation time slows with motion ? as speeds
  approach the speed of light (only from stationary
  frame of reference)
• Einstein tested theory ? synchronized 2 clocks ?
  one put on high-speed airplane, other on the
  ground
• Above result Time on airplane clock was slower
  than on ground clock

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Skewing, Length Contraction, Time Dilation and
Time Intervals (Page 3)

• Time Intervals If an airplane went at 90 of
  speed of light for 1 second, rider in the
  airplane would age 1 sec, but person on earth
  watching airplane would age 2.29 sec. over the
  same time period
• Clocks record interval between two spatial
  events time interval may differ depending on
  which frame of
• reference clock is in

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Conclusion

• Concepts that we have learned
• There is no such thing as an absolute (completely
  stationary) frame of reference everything is
  relative
• Laws of physics always apply equally to all
  frames of reference
• Speed of light constant in all frames of
  reference
• No simultaneity of events between different
  frames of reference
• Time does not slow and objects do not shorten as
  speed increases (only when viewed from another
  frame of reference)
• Speed does not increase with mass
• Nothing is faster than speed of light
• (How Stuff Works Conclusion)

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Works Cited

• G., P., ed. "Relativity." Britannica. 2001st ed.
  2002.
• Heckert, Paul A, and K. Lee Lerner. "Relativity,
  special." Gale Encyclopedia of Science. Ed. K.
  Lee Lerner and Brenda Wilmoth Lerner. 3rd ed.
  Detroit Gale, 2004. Student Resource Center -
  Gold. Thomson Gale. Sir Winston Churchill
  Secondary. 11 Oct. 2007 lthttp//find.galegroup.com
  /srcx/infomark.do?contentSetGSRCtyperetrievet
  abIDT001prodIdSRC-1docIdEJ2166031898sourceg
  aleuserGroupName39cuversion1.0gt.
• "Introduction to Special Relativity." Wikipedia.
  18 Sept. 2007. Wikipedia, the Free Encyclopedia.
  1 Oct.-Nov. 2007 lthttp//en.wikipedia.org/wiki/Int
  roduction_to_special_relativitygt.

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Works Cited Page 2

• Lorentz, H. A., et al. The Principle of
  Relativity. Trans. W. Perrett and G. B. Jeffrey.
  2nd ed. Toronto, Ontario Dover Publications,
  Inc., 1952.
• "RELATIVITY THE SPECIAL AND THE GENERAL THEORY."
  Scientific American Aug. 2006 1. Student
  Research Center. EBSCOhost. Churchill School
  Library. 10 Oct. 2007. Keyword Special
  Relativity Physics.
• Zavisa, John. "How Special Relativity Works." How
  Stuff Works. 1 Oct. 2007 lthttp//science.howstuffw
  orks.com/relativity.htmgt.