ELASTIC WAVES AND SOUND

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

I.I.S. “BERETTA” – LICEO SCIENTIFICO “MORETTI”

CLIL PHYSICS:

To ItalyThrough

From Finland

A wave has two main characteristics:

1. it is a travelling energy/disturbance; 2. it carries energy/disturbance from one place to another.

the nature of waves

We will consider two basic types of waves:

For transverse/longitudinal waves:the direction of the disturbance (displacement) is perpendicular/parallel to the direction of wave motion.

For transverse/longitudinal waves:the direction of the disturbance (displacement) is perpendicular/parallel to the direction of wave motion.

1) Choose the correct word:

A wave has two main characteristics:

1. it is a travelling energy/disturbance; 2. it carries energy/disturbance from one place to another.

the nature of waves

We will consider two basic types of waves:

For transverse/longitudinal waves:the direction of the disturbance (displacement) is perpendicular/parallel to the direction of wave motion.

For transverse/longitudinal waves:the direction of the disturbance (displacement) is perpendicular/parallel to the direction of wave motion.

1) Choose the correct word: KEYS

Transverse and longitudinal waves are called ………….. waves because they consist of regularly repeating …………….. that are produced over and over again by the ………….

periodic waves: spatial dependence

Example: draw a transverse momentum wave and define the amplitude and wavelength. These definitions also apply to longitudinal waves.

The ……………………….. is the maximum ……………………… of a particle from its undisturbed ……………………...

In the diagram, a single ............... of the wave is highlighted in colour. A wave is a …………… of these repeating cycles.

The …………………………….. is the spatial period of the wave in the direction of motion: the horizontal …………………. of one cycle of the wave or the distance between any two ……………………………. points with the same phase.

2) Fill in each gap the correct word from the list: position, patterns, amplitude A, periodic, successive, length,series, source, displacement, wavelength λ, cycle

Transverse and longitudinal waves are called periodic waves because they consist of regularly repeating patterns that are produced over and over again by the source

periodic waves: spatial dependence

Example: draw a transverse momentum wave and define the amplitude and wavelength. These definitions also apply to longitudinal waves.

The amplitude A is the maximum displacement of a particle from its undisturbed position

In the diagram, a single cycle of the wave is highlighted in colour. A wave is a series of these repeating cycles.

The wavelength λ is the spatial period of the wave in the direction of motion: the horizontal length. of one cycle of the wave or the distance

between any two successive points with the same phase.

2) Fill in each gap the correct word from the list: KEYS

A ………………… can be described as a function of ……………….. by observing the change in displacement of a ……………………….. point on the wave. As the wave passes,

the point under observation oscillates in ………………. harmonic.

periodic waves: time dependence

The period T [s] is the time ……………..

for ……………. complete cycle. It is related

to the ………………… by:f = 1/T [Hz].

For any periodic wave, the …………………..between period, wavelength, and speed is given by:

This relationship applies to longitudinal ………………… to transverse waves.

v T

f

3) Fill in each gap the correct word from the list: simple, required, as well as, one, relationship, time, single, wave, frequency.

A wave can be described as a function of time by observing the change in displacement of a single point on the wave. As the wave passes,

the point under observation oscillates in simple harmonic.

periodic waves: time dependence

The period T [s] is the time required

for one. complete cycle. It is related

to the frequency by:f = 1/T [Hz].

For any periodic wave, the relationship between period, wavelength, and speed is given by:

This relationship applies to longitudinal as well as to transverse waves.

v T

f

3) Fill in each gap the correct word from the list: KEYS

Sound is carried …….. longitudinal waves that are created ……. vibrating objects,

such ……. a guitar string …… human vocal cords, or the diaphragm ……. a loudspeaker.

A sound can be made ……. of several

overlapping waves with different frequencies.

A sound …….. a single frequency is called

a pure tone.

Sound can be created

or transmitted only …… a medium,

such as a gas, liquid, …… solid.

Sound cannot propagate

….. a vacuum.

the nature of sound

Sound has an associated frequency, which is the number of cycles ….. second

passing a given location.

4) Complete the text: the, or, by (2), with, as, up, of, in (2), per.

Sound is carried by longitudinal waves that are created by vibrating objects,

such as a guitar string, the human vocal cords, or the diaphragm of a loudspeaker.

A sound can be made up of several

overlapping waves with different frequencies. A sound with a single

frequency is called a pure tone.

Sound can be created

or transmitted only in a medium,

such as a gas, liquid, or solid.

Sound cannot propagate

in a vacuum.

the nature of sound

Sound has an associated frequency, which is the number of cycles per second

passing a given location.

4) Complete the text: KEYS

Sound travels through ……………………………………………………………………………

The speed of wave depends on …………………………………………………………………

the speed of sound

substance speed(m/s)

gases

air (20 °C) 343

helium (0 °C) 965

liquid

mercury (20 °C) 1,450

seawater (20 °C) 1,522

solid

copper 5,010

glass (pyrex) 5,640

steel 5,960

The speed of sound and the speed of light

5) Working in pairs, discuss the table and the picture:

The speed of light is ………………………………

Therefore, lightning and thunder …………………

Sound travels through gases, liquids, and solids at considerably different speeds

The speed of wave depends on the properties of the medium it is travelling in.

the speed of sound

substance speed(m/s)

gases

air (20 °C) 343

helium (0 °C) 965

liquid

mercury (20 °C) 1,450

seawater (20 °C) 1,522

solid

copper 5,010

glass (pyrex) 5,640

steel 5,960

The speed of sound and the speed of light

5) Working in pairs, discuss the table and the picture: KEYS

The speed of light is much greater than the speed

of sound. Therefore, lightning and thunder don’t reach the

observer at the same time ….

learning the basics

T F

1. You can hear only when vibrations are produced by your vocal cords.

2. Both longitudinal and transverse waves are characterised by an amplitude and a frequency.

3. Sound can be created in or transmitted through a gas, liquid, solid or vacuum.

4. Ultrasound wave has a greater wavelength than acoustic wave.5. Thunder reaches the observer well before than lightning.

6) Decide if the following statements are true or false:

learning the basics

T F

1. You can hear only when vibrations are produced by your vocal cords.

2. Both longitudinal and transverse waves are characterised by an amplitude and a frequency.

3. Sound can be created in or transmitted through a gas, liquid, solid or vacuum.

4. Ultrasound wave has a greater wavelength than acoustic wave.5. Thunder reaches the observer well before than lightning.

TT

F

FF

6) Decide if the following statements are true or false: KEYS

language practice

7) Match the hints in column one to the terms in column two:

1. A travelling disturbance that carries energy from one place to another.

2. The maximum displacement of a particle from its rest position.

3. The spatial period of a wave in the direction of its motion.

4. A mechanical disturbance of the particles in a solid, liquid, or gaseous medium.

5. The number of oscillatory cicles per second.

A

B

C

D

E

Wavelenght

Elastic wave

Frequency

Wave

Amplitude

language practice

7) Match the hints in column one to the terms in column two: KEYS

1. A travelling disturbance that carries energy from one place to another.

2. The maximum displacement of a particle from its rest position.

3. The spatial period of a wave in the direction of its motion.

4. A mechanical disturbance of the particles in a solid, liquid, or gaseous medium.

5. The number of oscillatory cicles per second.

D

E

A

B

C

Wave

Amplitude

Wavelenght

Elastic waveFrequency