© 1 physics in concert. © 2 objectives to understand how engineers use physics to set up a concert...
TRANSCRIPT
©1
Physics in concert
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Objectives
To understand how engineers use physics to set up a concert
LightingElectricitySound
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Microphone
Amplifier
Mixing desk
SoundA sound-system increases the volume of the sound.
Speaker
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Sound-systemA microphone is used to turn the sound wave from the music on the stage into an electronic signal.
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Sound-system
The electronic signal is sent via a mixing desk to the amplifier, which boosts the signal.
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Sound-system
The signal is turned back in to a (louder) sound by the speakers.
Ear
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Sound-pitch
Different musical instruments have different pitches.
High pitch
Low pitch
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Sound-pitch
High pitch sounds have a higher frequency
High pitch
Low pitch
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Signals for three different sound waves are shown below.
(i) which signal is from the loudest sound?
(ii) which signal is from the highest pitch sound?
Q1Q1
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Sound levels
• Sound levels are measured in decibels (dB)
Safe noise exposure
Hours Sound Level (dB)
8 85
4 90
1 100
1/4 110
0 120
120 dB or above can lead to instant hearing damage
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Sound-speed
Sound travels to the audience at a speed of 330 m/s
Speed = distance ÷ time
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Sound at a concert
The speed of sound is 330 m/s. How long it takes sound to travel 40 m?
Q2
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Lighting at a concert
Red, green and blue are used for stage lighting.
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Lighting at a concert
Red Green
Blue
Cyan
Yellow
Magenta
Other colour effects can be produced by mixing these three lights.
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Lighting at a concert
The colour an object appears depends on the colours it absorbs or reflects.
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Lighting at a concert
The colour an object appears depends on the colours it absorbs or reflects.
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Lighting at a concertAn artist on stage wears a red T-shirt with a yellow star
motif, and blue trousers.
Complete the table showing how his costume appears under different colour lighting.
Q3
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Lighting at a concert
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Lighting at a concert
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Lighting at a concert
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Lighting at a concert
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Lighting at a concert
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Lighting at a concert
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Review: Colour mixing
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Making electricity
The electricity for outdoor concerts needs to be produced on-site using a generator.
Generator
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Supplying electricity
Thick cables are used to carry large electrical currents to the sound and lighting systems.
Plug-in points for sound or lighting equipment
Generator
Electrical cables
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Electrical current
The larger the current, the thicker the cable needed.
The current in the cables can be calculated using the relationship
current = power ÷ voltage
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Electrical currentA lamp with a power rating of 100 W. Calculate
the current that flows when it is connected to a 240 V supply.
Q4
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Electrical circuits
• The lighting and sound systems are connected in parallel to the generators
Generator
Lamp 1
Lamp 2
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Electrical circuitsExplain the difference between a series and
parallel circuit
Q5
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Engineers at a concert
Sound Engineer Electrical Engineer Lighting Engineer
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Choose an artist
• Each person in your team will take on a different role
• But first you must choose the artist or group you will represent…
2 minutes
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Select your role by looking at the key skills:
1Creative
Analytical
Visual
2Analytical
Using diagrams
Numerical
3Spatially aware
Analytical
Numerical
2 minutes
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Your role:
1
Lighting engineer
2Electrical engineer
3Sound
engineer
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Practice your skills
• Complete the practice your skills worksheet that goes with your role
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Planning a concert
Sound Engineer Electrical Engineer Lighting Engineer
• You will need to complete the task and poster sheet that goes with your role
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Artist requests
• Check the card to see what your artist has requested.
Sound Level
Performance area
Satellite speaker distance
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Sound engineers
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Lighting engineers
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Electrical engineers
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