Einstein's Theory of Special Relativity

Test yourself

Einstein's Theory of Special Relativity

Einstein had two postulates (theories) as part of his theory of special relativity.

Illustrative background for Einstein's first postulateIllustrative background for Einstein's first postulate ?? "content

Einstein's first postulate

  • Einstein’s first postulate of special relativity states that:
    • Physical laws have the same form in all inertial frames.
  • An inertial frame is one in which objects will not accelerate if they are left untouched by external forces (Newton’s first law).
  • This postulate essentially states that experiments will have the same result in any inertial frame of reference.
Illustrative background for Einstein's second postulateIllustrative background for Einstein's second postulate ?? "content

Einstein's second postulate

  • Einstein’s second postulate of special relativity states that:
    • The speed of light in free space is invariant.
  • This means that the speed of light will not change if the observer or the source is moving.

Jump to other topics

1Measurements & Errors

2Particles & Radiation


4Mechanics & Materials


6Further Mechanics & Thermal Physics (A2 only)

7Fields & Their Consequences (A2 only)

8Nuclear Physics (A2 only)

9Option: Astrophysics (A2 only)

10Option: Medical Physics (A2 only)

11Option: Engineering Physics (A2 only)

12Option: Turning Points in Physics (A2 only)

Go student ad image

Unlock your full potential with GoStudent tutoring

  • Affordable 1:1 tutoring from the comfort of your home

  • Tutors are matched to your specific learning needs

  • 30+ school subjects covered

Book a free trial lesson