How is Sound produced? By the end of the lesson you should be able to: 21/11/2019 How is Sound produced? By the end of the lesson you should be able to: Explain how sound is made. Describe how sound reaches our ears. Use the particle model to explain this Key words: (Can you think what they might mean?) Vibration Propagation -Write down objectives, key words and the date -Underline all of your work today’s title, lesson

What are waves? transverse longitudinal Waves transfer energy They can be transverse or longitudinal: transverse longitudinal The motion of the wave is at a right angle to the direction of the wave The motion of the wave is in the same direction as the wave

Copy this diagram and annotations 1) – 3). Air molecules 1) An object makes a sound by vibrating 2) The vibrations pass through air by making air molecules vibrate 3) These vibrations are picked up by the ear Copy this diagram and annotations 1) – 3). ADD to each part as much information as possible from page 175. You must include the words: compression/rarefaction or decompression/molecules/wavelength/frequency/high and low pressure/longitudinal This is a revision slide of material that they should be familiar with but the aim is more to get them to use the correct language/ reminded of

In your book pick one and explain how it produces sound

Speed of Sound Sound travels by particles vibrating. To understand this better you need to remember what the particles look like in a solid, liquid and a gas: solid liquid gas Which state does sound travel fastest through? Why? Sound travels fastest through solids because the particles are closer together than in a liquid and a gas, so the vibrations are more easily passed from particle to particle. In which state are the particles closest together? solid In which state are the particles furthest apart? gas

Air (330 metres per second) How fast? Air (330 metres per second) Water (1500 metres per second) Wood (3850 metres per second)

Speed of Sound Sound in a Vacuum Write down: Speed of Sound in Air = 330m/s Write down: What you heard in the demo. Explain why this happened.

Check your learning. Do you now understand: 21/11/2019 Check your learning. Do you now understand: How sounds are made? How they reach our ears? How fast sound travels in different media? The difference between pitch and intensity? How to describe a wave?

21/11/2019 Hearing and Noise By the end of the lesson you should be able to: Explain how the ear works? Know if a chicken can hear as well as a dog? How you can damage your hearing. Key words: (Can you think what they might mean?) Audible Noise pollution -Write down today’s title, lesson objectives, key words and the date -Underline all of your work

What does the caption say? 21/11/2019 What film is this? What does the caption say? Let’s watch the trailer… Think about why……

Intensity: loud or soft Pitch and Intensity Pitch: high or low Intensity: loud or soft Copy then hand out white boards for the following quiz type slides.

Mouse Rock Concert Thunder Cat Purring

Recap of what happens when you vary the parameters.

Put it all together!!! Match the oscilloscope traces to the source of the sound. B C D A 1. A flute playing a single clear note Quick quiz. 2. A dog whistle 3. A milk bottle dropped onto a floor 4. A rumble of thunder

How The Ear Works Work through and explain. Get them to re-explain back.

1.Sound waves are collected by the ear lobe or pinna. 6.The auditory nerve takes the signals to the brain. 6 4 1 2 3 5 2.The waves travel along the ear canal. 5.The cochlea turns these into electrical signals. Reinforcing and provide Framework 8Ld3 sheet which is a cut and stick ear hearing sequence. 3.The waves make the ear drum vibrate. 4.The small bones amplify the vibrations.

Audible Range Audible Range = The frequency range over which we can hear. 20Hz – 30,000Hz, for children. Decreases the older you get, to ~ 20,000Hz. Check out what they can hear at http://www.freemosquitoringtone.org/ If you dont have a frequency generator at hand.

How loud are sounds? 150 140 120 100 80 60 40 20 10 Personal stereo Personal stereo Gunshot blast Permanent ear damage Aircraft overhead Max human voice Loud bell A circular saw at 2m No need to copy Quiet countryside Recording studio Pin being dropped Can just be heard

-measured in Decibels (dB) Loudness Scale Could copy this one down if time -measured in Decibels (dB)

Hearing Damage Inner Ear Middle Ear Outer Ear Flattened Cilia Fluid build-up/an infection Inner Ear Hearing Damage Middle Ear Talk through Outer Ear Perforated ear drum 3-small bones (fused together) Wax build-up

Audible Range Which goes with which? Dog Mouse Bat Beluga Whale Chicken 1000Hz to 91,000Hz 125Hz to 2,000Hz 67Hz to 45,000Hz 1000Hz to 123,000Hz 2000Hz to 110,000Hz

Audible Range Dog 67Hz to 45,000Hz Mouse 1000Hz to 91,000Hz Bat Beluga Whale 1000Hz to 123,000Hz Chicken 125Hz to 2,000Hz

Ultrasound By the end of the lesson you should be able to: 21/11/2019 Ultrasound By the end of the lesson you should be able to: What is ultrasound? How is it useful? Key words: echolocation -Write down today’s title, lesson objectives, key words and the date -Underline all of your work

21/11/2019 What is ultrasound? Sound waves that have a frequency of above 20,000Hz There are many uses! Bat echo location Dolphins finding fish Monitoring unborn babies and other soft internal tissue

Uses of ultrasound By animals: Bats – produce ultrasound pulses to detect prey (insects) and to navigate in dim light.

Uses of ultrasound By animals: Dolphins – produce ultrasound pulses to detect prey (fish) and to detect predators. It is possible that they use ultrasound to communicate.

Uses of ultrasound Medicine: Observing unborn babies – ultrasound can image a child in the womb to enable doctors to check their condition before birth.

Uses of ultrasound Medicine: Observing soft tissue damage – ultrasound can image the digestive tract and can be used to break down dangerous accumulations of minerals such as kidney stones

21/11/2019 Spare Slides 29

What’s vibrating? Why does it break? http://www.wellesley.edu/Physics/Rberg/glass-shattering.mov

How The Ear Works D A C E F B Sound travels along the ear canal and makes the eardrum vibrate. The electrical signals travel along the nerves to the brain. Eardrum vibrations are passed on, and magnified by three small bones. The ear catches sound and funnels it into the ear canal. The three bones touch one another and pass on the vibration. The vibrations turn into electrical signals in the inner ear. Quick recap quiz D A C E F B

Teaching points: What is a noise reduction rating? How do ear plugs work – think in terms of the PM, how does sound proofing in general work etc? How would you make them have a higher dB rating – do you have to consider differences in pressure inside and outside the inner/outer ear?