Title: Sound Waves

True or false:1. Waves always travel through a solid2. Frequency affects the pitch of a noise3. A high frequency means the wavelength will

be long4. A low amplitude means the noise will be loud5. Sound waves can travel through water6. Sound waves are caused by vibrating objects7. Dogs can hear sounds at a higher frequency

than humans.EXT: Rewrite the false statements so they are correct

Title: Sound Waves

True or false:1. Waves always travel through a solid2. Frequency affects the pitch of a noise3. A high frequency means the wavelength will

be long4. A low amplitude means the noise will be loud5. Sound waves can travel through water6. Sound waves are caused by vibrating objects7. Dogs can hear sounds at a higher frequency

than humans.

Sound Waves

L/O: To recap sound waves and differentiate between ultrasound and infrasound.

Describe Ultrasound and its uses (too high frequency to hear 20KHz+)Calculate depth or distance from time and velocity of ultrasound pulsesDescribe Infrasound and its uses (too low to hear 20Hz-)

JCX - Y11 W+R

Wavelength

Wavelength

Amplitude

Amplitude

Vibration Direction of travel

JCX - Y11 W+R

1 2

0

2

1

1

2

Height (m)

Time (s)

Frequency – The number of waves per second. If one wave passes in one second it has a frequency of one Hertz or Hz. This is the unit of frequency.

PPQKnowledge

PPQ

wavelength

amplitude

Knowledge

Longitudinal and Transverse

There are two types of waves: Longitudinal and transverse.

They move differently and have difference effects.

• Gas particles in the air are easily __________.

How vibrations make waves

compressed

If a vibrating object moves towards air particles……

…the air particles get squashed together. This is called compression.

The air particles can spread out again. This is called rarefaction.

High pressure/Compression

Low pressure/rarefaction

Pressure changes caused by vibrations

From vibration to sound wave

• Draw a sound wave for a loud and quiet sound.

• Draw a sound wave with a long and short wave length.

• Draw a sound wave with a high frequency.

Comprehension

Use your knowledge of sound waves to explain the poster for Alien.

Application

http://www.noiseaddicts.com/2009/03/can-you-hear-this-hearing-test/

https://www.youtube.com/watch?v=WabT1L-nN-E

Copy the diagram (you don’t need to draw the animals)

Infrasound Infrasound is a sound that is below the range of human hearing (i.e. below 20 Hz). Some animals use infrasound to communicate.

We can use it to listen for these animals.

Infrasound Infrasound is also produced by volcanoes and earthquakes. Some people believe that animals can sense these infrasounds before the eruptions or earthquakes start.

https://www.youtube.com/watch?v=cphOwrGPe7Y

Infrasound Infrasound is also produced when meteors pass Earth. We can listen for these using specialist equipment. This means we can be more prepared for a meteor landing on Earth, which could cause considerable damage.

Infrasound Vladimir Gavreau was an infrasound pioneer.

While conducting experiments in the 1950s he became aware that his lab assistants were experiencing pain due to low frequency sounds.

He used this information to produce and infrasound gun. This was lethal as it rapidly induced internal bleeding when used on humans.

At low power it would shake walls and ceilings to pieces.

Whales, alligators, elephants and rhinos all communicate by infrasound.

Plenary

• Answer questions 1-8 in your revision pack.

• DO NOT LOSE THESE THIS TIME!!!!!!!