The Doppler Effect

Front

What is the Doppler Effect?

Back

The Doppler Effect is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source.

Front

Which type of wave travels faster through the air?

Back

Light travels faster than sound through the air.

Front

What happens to the pitch of a sound when the source moves away from the observer?

Back

The pitch of the sound decreases, making it sound lower.

Front

What happens to the pitch of a sound when the source moves towards the observer?

Back

The pitch of the sound increases, making it sound higher.

Front

If an ambulance is moving towards you, how does its siren sound?

Back

The siren sounds high-pitched as it approaches.

Front

If an ambulance is moving away from you, how does its siren sound?

Back

The siren sounds low-pitched as it moves away.

Front

What is the relationship between speed and frequency in the Doppler Effect?

Back

As the speed of the source increases, the frequency of the sound waves increases when approaching and decreases when receding.

Front

What is a practical example of the Doppler Effect?

Back

A common example is the change in pitch of a passing train's whistle as it approaches and then moves away from an observer.

Front

How does the Doppler Effect apply to light waves?

Back

The Doppler Effect can cause light waves from a moving object to shift towards the red end of the spectrum if moving away, or towards the blue end if moving closer.

Front

What is redshift?

Back

Redshift is the phenomenon where light from an object moving away from the observer shifts to longer wavelengths, appearing redder.