FROM THE SCIENCE LAB
Volume, Decibels and Forces Ultrasound The Secrets of Sound Ruben s Tube Puppets!
Prokofiev wrote his first opera aged nine Each character in the story represented by a different instrument or group of instruments: can you remember which are which? Peter Bird Duck Cat Wolf How do these instruments work?
How does the musician make sound? Make strings vibrate by rubbing bow What makes the sound louder? Amplify the sound through soundbox/ resonator How do the strings pass the vibrations on? Top of soundbox = sound board- a vibrating piece of wood Vibration from strings is picked up by the bridge Strings rest on the bridge near one end. Bridge then transfers the vibrations to the sound board
(Think back to rubber bands) How do strings produce different notes: Length - Longer strings vibrate slower and make lower sounding notes than shorter strings. Weight - Heavy, thick strings make lower notes than lighter thin strings. Tightness - A tight string makes a higher note than a loose string.
How does the musician make sound? Brass instruments get their sound from the vibrations of the musician's lips. Lips >> mouthpiece >> blowing. Vibration between the lips and mouthpiece >> air to vibrate down the long brass tube. How do you vary the note/ tone/ loudness? Control vibration of lips. The tube is stopped at one end Pitch = changing the length of the tube All those tubes help the instrument to make different sounds and notes. Buttons = valves. Pressing the valves adds length to the tube. Slide is used in the trombone. Tube = bore End = bell The shape, width, and length of the bore and bell have a lot to do with the tone of the brass instrument.
How does the musician make sound? Blowing air into or across the mouthpiece Create vibrations that make sounds and notes. How can you create vibrations? The flute family Creates sounds when air is blown across an edge. Air gets split by the edge causing vibrations at the mouthpiece Reed instruments Vibrations are made when the air travels across a thin piece of wood Reed vibrates making the sound We can have one or two reeds
Solid 14K gold Haynes flute #54321
A sound wave is created as a result of a vibrating object. The vibrating object could be: Vocal cords String and soundboard of a guitar or violin A tuning fork Diaphragm of a radio speaker. Objects vibrate at a particular frequency = natural frequency A flute tends vibrates at a single frequency >> a very pure tone Objects that produce a set of frequencies with a whole number mathematical relationship between them >> rich sound Flute Tuba Dropping a Pencil 200 Hz 200 Hz 197 Hz 400 Hz 211 Hz 600 Hz 217 HZ 800 Hz 219 Hz 1000 Hz 287 Hz 407 Hz
Sound waves combine and the waveforms show that the first tuning fork [A] has twice the frequency of the second one [B]. The combination [C] produces a sound equal to the differences in frequencies and the altered shaped of the waveform [green curve] shows that it has changed its tone. Two waves that are only slightly different in frequency combine to give a slow beating (pulsing) sound. The waveforms of a flute [A], oboe [B], and clarinet [C] show the differences in tone of the instruments. The flute's rounded waveform indicates a gentle, fluid sound. The clarinet wave has a similar shape with 'jinks' reflecting the instrument's more reedy sound. The jagged waveform of the oboe shows that its sound is even more reedy.
https://youtu.be/ude8ppjawki Finger sticks and slides around the edge and this action causes the vibrations The vibration you put in is just the right frequency to get the whole glass and water vibrating
Rub on the handles at the top of the bowl you will produce waves in the water inside Constructive Interference- the waves add you will get a very large standing wave at the edge and it looks like the water is spouting out of the sides. This gives you hot and cold spots in microwaves
When you sing air molecules vibrate > strike the rubber balloon membrane. > mirror wiggles. The laser light bounces off this wiggling mirror, tracing out shapes and patterns The different amplitudes and frequencies of the sounds emanating from your mouth cause different shapes and patterns. The harmonic motions traced out by the moving laser beam are called Lissajous patterns.
What is a force? PUSH PULL TWIST
What do forces make things do? move faster move slower start moving accelerate stop moving change shape change direction
What forces can you think of? Gravity Friction Air Resistance Water Resistance Surface Resistance Magnetic Forces
Newton said: Objects continue to move at a constant speed unless acted upon by an external net force. No Friction! NEWTON S FIRST LAW.
Astronauts need to beware! The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object) NEWTON S SECOND LAW.
Newton also said: Every action has an equal and opposite reaction. NEWTON S THIRD LAW Which explains why cannons recoil and how rocket engines work.
Where do we feel most least friction?
Why do forces matter in music? Strings don t move until they are struck with the pick or plucked with ones fingers. A world with no friction/ Newton s First Law? Strings would move forever All six of the strings are a different thickness > different mass. Strings needs a different amount of force to get them moving Apply little force to the string when you strum it then, the string will give an equal reaction. The reaction will include how much noise the instrument will make. The more force that is applied the loader the noise the guitar will make. Newton s third law of motion: every action there is an equal and opposite reaction.
One tenth of a bel Unit of measure of loudness of sounds to normal human ears The power of the ear to distinguish differences in loudness decreases as volume increases Your ears can hear everything from your fingertip brushing lightly over your skin to a loud jet engine. The bel scale is logarithmic = each unit is 10 times the preceding one A barely audible whisper measures one bel (10 decibels) and a speeding express train about 10 bels (100 decibels) Loud sound can actually damage your ears and cause loss of hearing. Even sounds as loud as 85 decibels can ruin your ears if you listen to them over a long period of time.
Humans can hear frequencies of 15 hertz to 20,000 times per second (Hz) Sound waves of more than 20,000 Hz are known as ULTRASONIC and cannot usually be heard by humans. Ultrasound by animals, and in medicine, in ship navigation, and in industry. Using ultrasound depends on an echo (or reflection): An ultrasonic wave is produced and released by an electrical device. The ultrasonic wave hits a solid surface. The ultrasonic wave is reflected off the surface and bounces back (like an echo in an empty cave). The ultrasonic wave is picked up from a receiver. This is repeated to get the object's shape and direction from the ultrasound device.
Detection Medicine Ultrasound can be used to examine the number, sex, movement, and heart beat of a baby inside a mummy s tummy, the stage of the pregnancy, and whether the baby is healthy Heat production As therapy for muscle pain (can accelerate wound healing). Breaking down particles To clean teeth (used by dentists to remove plaque without damage or pain. Industry Detection To navigate under water. Submarines and boats use SONAR (sound navigation and ranging) to detect objects underwater. As quality control. Ultrasound can be used to detect cracks in metal and plastic that is made in factories. This is because the ultrasonic waves reflect off cracks more than the metal or plastic. Heat production To heat liquids (dry corn milling plants enhance ethanol production using heat produced by ultrasound). Breaking down particles To clean jewelry, lenses, and clothes. Objects are placed in an ultrasound bath, in which ultrasound is passed through water and creates bubbles that remove the dirt. Ultrasonic washing machines are currently under development.
https://youtu.be/hpovwbpgeoo
Pitch is how fast the sound wave is oscillating, the frequency. Not the same as the speed of sound (340 m/s-1) Higher frequency = higher pitch A big heavy guitar string will vibrate slowly and create a low sound or pitch. A thinner lighter string will vibrate faster and create a high sound or pitch. Dogs can hear sound at a higher frequency than humans > hear noises that we can t Doppler Effect = If you are standing still and a car drives past you, the frequency of the sound will change as the car passes you. Sound pitch higher as the car is coming towards you and then lower as the car moves away. The sound the car is producing is not changing, the frequency is the same. Car is traveling towards you the speed of the car is causing the sound waves to hit your ear faster or at a higher frequency than the car is making them.
Call of the Bat: Bats can fly through woodland in pitch black, eat spiders from webs and pluck fish from water all by using echolocation which means they make calls during flight, and listen to the echoes that return in order to map locations effectively seeing through sound. http://www.bbc.co.uk/programmes/p024m0l8 Dancing alligators: Male alligators make themselves vibrate underwater and put on a water display to attract females. And they ve been doing this since the dinosaurs were around. http://www.bbc.co.uk/programmes/p024m0h5 Dial-an-owl: The barn owl can pinpoint prey to the millimeter using their ears. Their two ears are in different places in order to listen to sound in different directions and to tell how high or low the sound is coming from. http://www.bbc.co.uk/programmes/p024m0bq
Cereal box Scissors Tape String Small brads Safety pin Sticks for puppeting
How are sounds produced? How fast do sound waves travel? What is a reflected sound called? How do we hear CDs? What damps sound in the Royal Albert Hall? How many octaves are in a note? Which instrument was Peter? What happens when we move our hand over the top of a glass? How do bats find locations? Which other animals are sound experts?