Download Document

Physics in concert
1
©
Objectives
To understand how engineers use physics to set up a concert
Sound
Electricity
2
Lighting
©
Sound
A sound-system increases the volume of the sound.
Speaker
Amplifier
Microphone
Mixing desk
3
©
Sound-system
A microphone is used to turn the sound wave from the
music on the stage into an electronic signal.
4
©
Sound-system
The electronic signal is sent via a mixing desk to the
amplifier, which boosts the signal.
5
©
Sound-system
The signal is turned back in to a (louder) sound by the
speakers.
Ear
6
©
Sound-pitch
Different musical instruments have different pitches.
High pitch
Low pitch
7
©
Sound-pitch
High pitch sounds have a higher frequency
High pitch
Low pitch
8
©
Q1
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?
9
©
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
10
©
Sound-speed
Sound travels to the audience at a speed of 330 m/s
Speed = distance ÷ time
11
©
Sound at a concert
Q2
The speed of sound is 330 m/s. How long it takes
sound to travel 40 m?
12
©
Lighting at a concert
Red, green and blue are used for stage lighting.
13
©
Lighting at a concert
Other colour effects can be produced by mixing these
three lights.
Yellow
Green
Red
Cyan
Magenta
Blue
14
©
Lighting at a concert
The colour an object appears depends on the colours it
absorbs or reflects.
15
©
Lighting at a concert
The colour an object appears depends on the colours it
absorbs or reflects.
16
©
Lighting at a concert
Q3
An 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.
17
©
Lighting at a concert
18
©
Lighting at a concert
19
©
Lighting at a concert
20
©
Lighting at a concert
21
©
Lighting at a concert
22
©
Lighting at a concert
23
©
Review: Colour mixing
24
©
Making electricity
The electricity for outdoor concerts needs to be produced
on-site using a generator.
Generator
25
©
Supplying electricity
Thick cables are used to carry large electrical currents to
the sound and lighting systems.
Electrical
cables
Plug-in points for sound
or lighting equipment
Generator
26
©
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
27
©
Electrical current
Q4
A lamp with a power rating of 100 W. Calculate the
current that flows when it is connected to a 240 V
supply.
28
©
Electrical circuits
• The lighting and sound systems are connected in parallel to the
generators
Generator
Lamp 1
Lamp 2
29
©
Electrical circuits
Q5
Explain the difference between a series and parallel
circuit
30
©
Engineers at a concert
• Different engineers are responsible for the sound,
lighting and electrical systems.
Sound Engineer
Electrical Engineer
31
Lighting Engineer
©
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
32
©
Select your role by looking at the key skills:
1
2
3
Creative
Analytical
Visual
Analytical
Using diagrams
Numerical
Spatially aware
Analytical
Numerical
2 minutes
33
©
Your role:
1
Lighting
engineer
2
Electrical
engineer
34
3
Sound
engineer
©
Practice your skills
• Complete the practice your skills worksheet that goes
with your role
35
©
Planning a concert
• You will need to complete the task and poster sheet that
goes with your role
Sound Engineer
Electrical Engineer
36
Lighting Engineer
©
Artist requests
• Check the card to see what your artist has requested.
Sound Level
Performance
area
Satellite speaker
distance
37
©
Sound engineers
38
©
Lighting engineers
39
©
Electrical engineers
40
©
41
©