Framework of relativity concept inventory. (We added ‘Theme’ column and reorganized the Table in original RCI paper[19]).
| Theme | Concept | Description | Questions |
|---|---|---|---|
| Principle | First postulate | The laws of physics are the same in all inertial reference frames. | 16, 18, 19, 20 |
| Second postulate | The speed of light in a vacuum is the same in all reference frames. | 3, 4 | |
| Inertial reference frame | A coordinate system in which a free particle will maintain constant velocity; in particular, the concept that all inertial frames are equivalent. | 1, 2 | |
| Causality | If two events are timelike separated, then the ordering of the events is fixed for all reference frames. | 9, 10 | |
| Effect | Relativity of simultaneity | If two events A and B are spacelike separated, then there exist inertial frames in which A precedes B, and others in which B precedes A. | 11, 12, 15, 21 |
| Time dilation | The time interval between two time like separated events is shortest in the reference frame for which the two events are at the same position. | 5, 6, 7, 8 | |
| Length contraction | The length of an object (defined as the space interval between two simultaneous events at either end of the object) is the longest in the frame in which the ends of the object are at rest, and is shorter in all other frames. | 13, 14, 17 | |
| Velocity addition | Velocities transform between frames such that no object can be observed traveling faster than the speed of light in a vacuum. | 22, 23 |