Elearning Waves 4z4c1d

E-LEARNING ON WAVES Learning Outcomes: (a) describe what is meant by wave motion as illustrated by vibrations in ropes and

springs and by waves in a ripple tank (b) show understanding that waves transfer energy without transferring matter (c) define speed, frequency, wavelength, period and amplitude (d) state what is meant by the term wavefront (e) recall and apply the relationship velocity = frequency x wavelength to new situations or to solve related problems (f) compare transverse and longitudinal waves and give suitable examples of each To access the soft copy of this e-learning worksheet: [email protected] : ILovePhysics

First URL: http://lgfl.skoool.co.uk/keystage4.aspx?id=318 Click on

under “4. Waves 1” and complete slides 1 to 11.

Second URL: http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel/waves/anint roductiontowavesrev1.shtml A. An introduction to waves What are waves? Waves are ______________ that transfer _____________ from place to place without matter - solid, liquid or gas - being transferred. Some waves must travel through a _____________. The substance is known as the ______________, and it can be ____________________. Sound waves and seismic waves are like this. They must travel through a medium. It is the medium that vibrates as the waves travel through. 1

Other waves do not need to travel through a substance. They may be able to travel through a medium, but they do not have to. Visible light, infrared rays, microwaves and other types of electromagnetic radiation are like this. They can travel through ________________. Electrical or magnetic fields vibrate as the waves travel through.

B. Next page (2), “Transverse and longitudinal waves”

i)

Transverse waves Direction of Energy Transport

Particle Movement ____________ and other types of ____________________________ are transverse waves. _________________ waves and S waves (a type of seismic wave) are also transverse

waves.

In

transverse

waves,

the

_________________

are

at

___________________ to the direction of travel.

You must load the following URLs to view the extra applets on transverse waves: 1. http://einstein.byu.edu/~masong/HTMstuff/WaveTrans.html 2. http://www.ngsir.netfirms.com/englishhtm/TwaveA.htm

(Click

on

“Select”

and

choose a point on the wave before you click “start”.) You must load http://www.youtube.com/watch?v=-8a61G8Hvi0&feature=related to view circular water waves using a ripple tank (view only the first 1 minute of the video clip). You must load http://www.youtube.com/watch?v=JXaVmUvwxww to view plane water waves using a ripple tank (view only the first 1 minute of the video clip). ii) Longitudinal waves 2

Direction of Energy Transport

Particle Movement _________________ and waves in a stretched spring are longitudinal waves. P waves (relatively fast moving longitudinal seismic waves that travel through liquids and solids) are also longitudinal waves. In longitudinal waves, the _________________ are along the ____________________ as the direction of travel.

You must load the following URLs to view the extra applets on longitudinal waves: 1. http://einstein.byu.edu/~masong/HTMstuff/WaveTrans.html 2. http://www.ngsir.netfirms.com/englishhtm/Lwave.htm (Click on “Select” and choose

a point on the wave before you click “start”. At the bottom of the applet, click on “Graph” and “Decolorize” to view the movement of a point on the wave.) C. Next page (3), “Amplitude, wavelength and frequency”

i)

Amplitude

As waves travel, they set up patterns of disturbance. The amplitude of a wave is its ____________________________________________________.

Take

care,

the

amplitude is not the distance between the top and bottom of a wave.

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Refer to diagram and fill up all missing words.

ii)

Wavelength

The wavelength of a wave is the ______________ between a point on one wave and the _____________________ on the next wave. It is often easiest to measure this from the crest of one wave to the crest of the next wave, but it doesn't matter where as long as it is the ______________________ in each wave. iii)

Frequency

The frequency of a wave is the ____________________________ produced by a source _________________. It is also the _____________________________ that a certain point ___________________. The unit of frequency is the __________________. It is common for kilohertz (kHz), megahertz (MHz) and gigahertz (GHz) to be used when waves have very high frequencies. For example, most people cannot hear a high-pitched sound above 20kHz, radio stations broadcast radio waves with frequencies of about 100MHz, while most wireless computer networks operate at 2.4GHz. Check your understanding of this section by having a go at the activity.

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D. Next page (4), “Wave Speed”

How fast do waves travel? The speed of a wave - its wave speed - is related to its ________________ and _______________, according to this equation (state the equation):

For example, a wave with a frequency of 100Hz and a wavelength of 2 m travels at:

Check your understanding of the equation by having a go at this activity.

Third URL: http://www.physicsclassroom.com/Class/waves/u10l2a.cfm The Anatomy of a Wave A. Transverse Waves

Refer to the information on the website and answer the following questions. What do the following represent? i) Dashed

line:

_______________________________________________________ ii)

Points

A,

E,

H:

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_____________________________________________________ The ____________ of a wave is the point on the medium which exhibits the _______________________________________________ displacement from the _________________________. iii)

Points

C

and

J:

_____________________________________________________ The ______________ of a wave is the point on the medium which exhibits the ______________________________________________ displacement from the _________________________. iv)

Distance of a line segment which is perpendicular to the rest position and extends vertically upward from the rest position to point A: _______________________ The ______________ of a wave refers to the __________________ of displacement of a particle on the medium from its _________________________.

v)

Horizontal distance from A to E, or the horizontal distance from B to F, or the horizontal distance from D to G, or the horizontal distance from E to H: ________________ The _______________ of a wave is simply the length of ___________________ wave cycle.

The wavelength can be measured as the distance from

___________________ or from _________________________.

B.

Longitudinal Waves

6

Refer to the information on the website and answer the following questions. What do the following represent?

i)

Points

A,

C,

E:

_____________________________________________________ A region where the coils are pressed together in a small amount of space is known as a ___________________. A ___________________ is a point on a medium through

which

a

longitudinal

wave

is

traveling

which

has

the

_____________________________. ii)

Points

B,

D,

F:

_____________________________________________________ A region where the coils are spread apart, thus maximizing the distance between coils, is known as a ___________________. A ___________________ is a point on a medium through which a longitudinal wave is traveling which has the _____________________________. iii)

The distance from point A to point C or from point B to point D: ________________ A ________________________ measurement is made by measuring the distance from

a

_______________________________________

or

from

a

_______________________________________. Check your understanding by answering the 3 questions.

Third URL: http://www.physicsclassroom.com/Class/waves/u10l2b.cfm A.

Frequency

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The frequency of a wave refers to how often the particles of the medium vibrate when a wave es through the medium.

In mathematical , the frequency is the

__________________________________________________ of a medium per a given amount of time (1 second).

B. Period Period refers to the time which it takes to do something. When an event occurs repeatedly, then we say that the event is periodic and refer to the time for the event to repeat itself as the period. The period of a wave is the __________ for a particle on a medium to make ___________________________________. C.

Relationship between Period and Frequency State the equation which shows the relationship between period and frequency:

Check your understanding by answering the 11 questions.

Fourth URL: http://www.physicsclassroom.com/Class/waves/U10L2e.cfm The Wave Equation State the equation which shows the relationship between speed, wavelength and period of a wave:

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Since the period is the ________________ of the frequency, the expression 1/f can be substituted into the above equation for period. Rearranging the equation yields a new equation of the form:

Check your understanding by answering all the questions at the bottom of the web page.

End of Worksheet!!!

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