top of page

# 9.5. Doppler Effect

We have all hear the Doppler effect in action when standing next to fast moving traffic. It is the NEEEEEEEEEOOOOOOOOOOW (spelling?) noise a car or motorcycle makes when it drives past you at speed. There are a million videos demonstrating this effect on YouTube - I like this one as he demonstrates it whilst playing Careless Whisper.

In this section we look at some of the maths behind Doppler shift. Given the speed of the source and/ or observer we will learn how to calculate the perceived increase or decrease in frequecy. We will also look at Doppler shift of electromagnetic waves - otherwise known as red shift. The section has been divided up as follows:

â€‹

Doppler Effect

## Video Lessons

 Chris Doner Doppler Effect IB Specific Khan Academy Intrroduction to Doppler Doppler Equation Physics Online Doppler Effect

## Resources

 IB Physics Topic 9 Notes IB-Physics.net Chapter 9 Summary IB Revision Notes Isaac Physics Doppler Effect Level 4 Beyond IB Mr. G 9.5 Teaching Notes 9.5 Student Notes

## Questions

 Cambridge University Press Topic 9: Add Qs Topic 9: Add Qs MS Topic 9: MCQs CUP Website Link Freely available online Dr French's Eclecticon Interference, Doppler, Polarisation Interference, Doppler, Polarisation Solutions Link to Dr French's Site Extension: Pre-University Material Grade Gorilla 9.5 (Doppler) MCQ Topic 9 (Waves) End Quiz Quick IB Specific Mixed MCQs Mr. G 9.5 Formative Assessment Topic 9 Summary Qs IB Specific Questions
Moving Source/ Observer

#### Moving Source and Moving Observer

The follow simulation by Geogebra allows you to change the source and observer velocity and determine the effect on the perceived frequency. Write out the two equations, and make sure you are confident in each case whether to use a '+' or '-' sign.

## Video Lessons

 Chris Doner Moving Source/ Observer IB Specific Khan Academy Moving Source Reflection (Double Doppler)

## Resources

 IB Physics Topic 9 Notes IB-Physics.net Chapter 9 Summary IB Revision Notes Isaac Physics Doppler in 1D Level 4 Beyond IB Mr. G 9.5 Teaching Notes 9.5 Student Notes

## Questions

 Cambridge University Press Topic 9: Add Qs Topic 9: Add Qs MS Topic 9: MCQs CUP Website Link Freely available online Grade Gorilla 9.5 (Doppler) MCQ Topic 9 (Waves) End Quiz Quick IB Specific Mixed MCQs Mr. G 9.5 Formative Assessment Topic 9 Summary Qs IB Specific Questions
Electromagnetic Doppler

## Video Lessons

 Chris Doner EM Doppler IB Specific Khan Academy Red Shift Intro

## Resources

 IB Physics Topic 9 Notes IB-Physics.net Chapter 9 Summary IB Revision Notes Isaac Physics Doppler EM Level 4 Beyond IB Mr. G 9.5 Teaching Notes 9.5 Student Notes

## Questions

 Cambridge University Press Topic 9: Add Qs Topic 9: Add Qs MS Topic 9: MCQs CUP Website Link Freely available online Dr French's Eclecticon Interference, Doppler, Polarisation Interference, Doppler, Polarisation Solutions Link to Dr French's Site Extension: Pre-University Material Grade Gorilla 9.5 (Doppler) MCQ Topic 9 (Waves) End Quiz Quick IB Specific Mixed MCQs Isaac Physics Red Shift Hubbles law not relevant Mr. G 9.5 Formative Assessment Topic 9 Summary Qs IB Specific Questions

... and another little Physics joke to finish - DrR

"A cop pulls over a physicist for running a red light. The physicist tells the cop that from his point of view, the light was green, not red. So the cop gives him a speeding ticket."