Doppler effect
E176983
The Doppler effect is the change in frequency or wavelength of a wave perceived by an observer moving relative to the source of the wave, commonly experienced with sound and electromagnetic waves.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Doppler effect canonical | 4 |
| Doppler | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T1564887 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Doppler effect Context triple: [Ives–Stilwell experiment, category, Doppler effect]
-
A.
Zeeman effect
The Zeeman effect is the splitting of atomic or molecular spectral lines into multiple components when subjected to an external magnetic field, revealing information about energy levels and magnetic moments.
-
B.
Hertzian waves
Hertzian waves are early experimentally demonstrated electromagnetic waves that confirmed James Clerk Maxwell’s theory of electromagnetism and paved the way for modern radio communication.
-
C.
Tolman–Ehrenfest effect
The Tolman–Ehrenfest effect is a relativistic thermodynamic phenomenon stating that, in a system at thermal equilibrium within a gravitational field, temperature varies with gravitational potential so that hotter regions occur deeper in the gravitational well.
-
D.
Kapitza–Dirac effect
The Kapitza–Dirac effect is a quantum phenomenon in which a beam of particles, such as electrons or atoms, is diffracted by a standing wave of light, demonstrating the wave-particle duality of matter.
-
E.
Unruh effect
The Unruh effect is a predicted phenomenon in quantum field theory where an accelerating observer perceives what inertial observers consider vacuum as a warm bath of particles with a characteristic temperature.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Doppler effect Target entity description: The Doppler effect is the change in frequency or wavelength of a wave perceived by an observer moving relative to the source of the wave, commonly experienced with sound and electromagnetic waves.
-
A.
Zeeman effect
The Zeeman effect is the splitting of atomic or molecular spectral lines into multiple components when subjected to an external magnetic field, revealing information about energy levels and magnetic moments.
-
B.
Hertzian waves
Hertzian waves are early experimentally demonstrated electromagnetic waves that confirmed James Clerk Maxwell’s theory of electromagnetism and paved the way for modern radio communication.
-
C.
Tolman–Ehrenfest effect
The Tolman–Ehrenfest effect is a relativistic thermodynamic phenomenon stating that, in a system at thermal equilibrium within a gravitational field, temperature varies with gravitational potential so that hotter regions occur deeper in the gravitational well.
-
D.
Kapitza–Dirac effect
The Kapitza–Dirac effect is a quantum phenomenon in which a beam of particles, such as electrons or atoms, is diffracted by a standing wave of light, demonstrating the wave-particle duality of matter.
-
E.
Unruh effect
The Unruh effect is a predicted phenomenon in quantum field theory where an accelerating observer perceives what inertial observers consider vacuum as a warm bath of particles with a characteristic temperature.
- F. None of above. chosen
Statements (57)
| Predicate | Object |
|---|---|
| instanceOf |
frequency shift
ⓘ
physical phenomenon ⓘ wave phenomenon ⓘ |
| appliesTo |
electromagnetic waves
ⓘ
seismic waves ⓘ sound waves ⓘ water waves ⓘ |
| cause |
relative motion between observer and medium
ⓘ
relative motion between source and medium ⓘ relative motion between source and observer ⓘ |
| dependsOn |
angle between motion direction and line of sight
ⓘ
velocity of observer ⓘ velocity of source ⓘ wave propagation speed in medium ⓘ |
| describes |
change in observed frequency of a wave
ⓘ
change in observed wavelength of a wave ⓘ |
| field |
acoustics
ⓘ
astronomy ⓘ electromagnetism ⓘ medical imaging ⓘ physics ⓘ wave physics ⓘ |
| firstProposedBy | Christian Doppler ⓘ |
| hasConsequence |
frequency decrease when source and observer recede
ⓘ
frequency increase when source and observer approach ⓘ wavelength decrease when source and observer approach ⓘ wavelength increase when source and observer recede ⓘ |
| hasExample |
frequency shift of moving train horn
ⓘ
pitch change of passing siren ⓘ spectral line shift of receding galaxy ⓘ |
| hasType |
Doppler shift in astronomy
ⓘ
acoustic Doppler effect ⓘ classical Doppler effect ⓘ longitudinal Doppler effect ⓘ optical Doppler effect ⓘ relativistic Doppler effect ⓘ transverse Doppler effect ⓘ |
| mathematicalForm | f′ = f (c ± v_o) / (c ∓ v_s) ⓘ |
| namedAfter | Christian Doppler ⓘ |
| relatedTo |
blueshift
ⓘ
redshift ⓘ special relativity ⓘ wave equation ⓘ |
| usedIn |
Doppler lidar
ⓘ
Doppler ultrasound ⓘ astronomical spectroscopy ⓘ blood flow measurement ⓘ echocardiography ⓘ measurement of exoplanet radial velocities ⓘ measurement of radial velocities of galaxies ⓘ measurement of radial velocities of stars ⓘ navigation systems ⓘ police speed radar ⓘ radar speed measurement ⓘ satellite communication ⓘ weather radar ⓘ |
| yearProposed | 1842 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Doppler effect Description of subject: The Doppler effect is the change in frequency or wavelength of a wave perceived by an observer moving relative to the source of the wave, commonly experienced with sound and electromagnetic waves.
Referenced by (5)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Doppler