Faster than the Speed of Sound: Sonic Boomer (2)
This activity for pupils aged 9 -14 years old, builds on the work completed in Sonic Boomer
(1) and seeks to demonstrate how we can better understand how sound waves travel away
from their source and toward us.
As BLOODHOUND SSC travels faster than the speed of
sound, a Sonic Boom will be heard as the pressure
changes very rapidly across shock waves. The car
carries the sonic boom with it as it travels at
supersonic speeds.
Aim
To use a loud and consistent noise source to demonstrate that sound travels away from its
source and toward the receptor who can hear the sound waves.
Learning Objectives
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That sound travels over distance
That sound travels away from its source towards the receptor
That sounds become fainter over the distance they travel.
Programme of Study at Key Stage 2
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Differentiation
 All children will learn that sound becomes fainter the further you are from its source.
 Most children will learn that we measure the volume of sound in decibels.
 Some children will be able to explain the time and speed at which sound travels over
a set distance.
Resources
1. Bloodhound SSC Sonic Boomer
2. Stop watch
3. Tape measure or distance measuring wheel (Clicker Wheel).
4. Noise meter (optional)
Vocabulary
Sound
Sound wave
Distance
Source
Decibel
Receptor
Sonic Boom
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Faster than the Speed of Sound: Sonic Boomer (2)
Scientific Discovery
1. Print copies of the Discovery Sheet. To view Discovery Sheet, click here:
2. This is an outdoor activity and requires space such as a large playground or school
field.
3. Form small groups of four or more.
4. One person in each group uses the Sonic Boomer the others place themselves at
ever increasing distances further from the origin of the noise source.
5. If the students have a sound meter they can record the sound level at each distance,
if not they can agree as a group if the sound is getting louder, softer or staying the
same. Alternatively you can use the free download of Audacity to a laptop and use
the sound meter function.
6. Making the Sonic Boomer, boom is a physical activity similar to dropping ones arm
as a signal.
7. Children set their stopwatches to time the making of the noise until they hear the
sound.
8. Question: Is there a time lag between dropping the arm and hearing the sound?
9. At distances of over 500 metres the time lag should be quite marked.
10.Children could try to calculate the speed of sound: speed = time
distance
11. Children collaborate to understand that sound travels away from its source, losing
strength over distance.
What Went Well?
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Was it easy to set up this experiment?
Was it easy to organise your experiment?
Did the Sonic Boomer make the same noise all the time?
Was it softer if you flicked it softly, louder if you flicked it harder?
Was it easy to hear?
Was it easy to see what was happening and to record your findings?
How did you record your findings?
Did you find it easy to understand what was happening in your experiment?
Was it what you expected to happen?
Were you surprised by what happened?
Did you present your finding to the class?
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Faster than the Speed of Sound: Sonic Boomer (2)
Scientific Discussion
BLOODHOOUND SSC in breaking the World Land Speed Record will have to use forces to its
advantage and cope with them when they are opposed to a car travelling at 1,000 mph
When driver, Andy Green drives BLOODHOUND SSC faster than the
speed of sound, a Sonic Boom will be heard as the pressure changes
very rapidly across shock waves. The car carries the sonic boom
with it as it travels at supersonic speeds.
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When air is disturbed is sends out a pressure wave.
As this pressure wave hits our eardrums we hear sound.
We call this pressure wave, a sound wave.
As BLOODHOUND SSC travels faster than the speed of sound, it disturbs the air very
rapidly, causing a shock change in pressure, a shock wave, which also increases the
drag.
This sudden change in pressure and increase in drag makes accelerating past the
speed of sound very difficult, hence the term; ‘Sound Barrier’.
The car has been designed to overcome this with its shape and design.
As the car passes from sub-sonic to supersonic travel the sudden air pressure
changes spread out in shock waves. This sudden change in pressure is heard as a
loud bang which is referred to as a Sonic Boom.
Your BLOODHOUND SSC Sonic Boomer also produces a small scale sonic boom, the
noise you hear as you flick it downward. We used this noise to study how noise
travels over distance.
What other things might produce a sonic boom?
You could conduct further research into this.
Discuss this with your group or friends and plan further research.
Write down your discussion, present it to your class, Inspire others with your opinions.
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Faster than the Speed of Sound: Sonic Boomer (2)
Curriculum Links
Mathematics Using and applying shape, space and
measures
Communication
Reason
Properties of shapes
Measures
Science
Sc1
1e, 1f, 1g
1h
2a, 2b, 2c, 2d
4a, 4b, 4c
Ideas and Evidence in Science
Investigative Skills
Obtaining & Presenting Evidence
Considering Evidence
Changing materials
Forces in motion
Making & Detecting Sounds
Knowledge, skills and understanding
Communication
1a, 1b.
2a, 2b, 2c, 2d
2e, 2f, 2g, 2h.
2i, 2j, 2k, 2l, 2m.
2f
2a,2b,2c
3c, 3d
1a, 1b, 1c, 1d.
2a, 2b.
En1
Speaking & Listening
1a, 1b, 1d
En3
Composition
1a, 1e
Sc3
Breadth of Study
English
1a, 1b, 1c, 1d
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Faster than the Speed of Sound: Sonic Boomer (2)
Discovery sheet
Aim:
To conduct an experiment to demonstrate that sound travels away from its source and toward the
receptor who can hear the sound waves.
What you can use:
Bloodhound SSC Sonic Boomer
Stop Watch
Tape measure or distance wheel (Clicker Wheel)
Noise Meter
What you plan to do:
What you expect to happen:
What you will change or keep the same:
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Faster than the Speed of Sound: Sonic Boomer (2)
What actually happened?
Conclusion
Explain what happened and say What Went Well in your experiment.
Explain what you changed or might change if you did the experiment again.
What effect did this have or may have on your experiment.
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Faster than the Speed of Sound: Sonic Boomer (2)
Definitions
Sonic Boom
A sonic boom is the noise created and heard from the shock waves created by an object, in
our case, BLOODHOUND SSC, as it travels through air faster than the speed of sound.
When BLOODHOUND SSC is not moving, the air around it is not disturbed by the car and no
sound is created.
As the car moves and its speed increases, the sound waves in front of the car begin to get
squashed up together.
As BLOODHOUND SSC reaches the speed of sound, approximately 760 mph, called Mach 1,
the car is travelling at the same speed as sound. The car can no longer at this point transmit
sound waves forward only backwards.
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Faster than the Speed of Sound: Sonic Boomer (2)
The sound waves bunching up at the front of the car form a shock wave. This shock wave
makes a large noise that we call a sonic boom.
When BLOODHOUND SSC is travelling at supersonic speeds you will not hear any sound
coming toward you. It is only after the car passes that you will hear the sound generated by
the car.
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Faster than the Speed of Sound: Sonic Boomer (2)
Sound
Sound is made by pressure waves through something like air or water. Any movement
through air will make one air molecule bump into the next molecule and so on. We receive
this ‘disturbance’ of air in our ears (our receptors) and we call this disturbance, sound.
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