Transcript Slide 1
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 ©