I can: compare and contrast different types of wave Do Now: What do you know about waves? Draw a...

I can: compare and contrast different types of wave

Do Now: What do you know about waves? Draw a concept web

• A wave is a rhythmic disturbance which carries energy through space or matter.

A medium is a material through which a wave transfers energy.

Types of Waves

• Based on the way they move, there are 3 different types of waves:

1. Transverse Waves

2. Compressional Waves

3. Electromagnetic waves

Transverse Waves• In a transverse wave, the wave's medium

move perpendicular to the direction of the wave. Ex. ocean waves, light waves

• For example, as the wave moves left to right, the medium moves up and down.

• Say you're waterskiing down at the lake and you wipe out. As you float in the water and a wave goes by, what does your body do as the wave passes?

Parts of a Transverse WaveThere are 4 main parts to a transverse wave:

• Crest- the highest point on a transverse wave

• Trough- the lowest point on a transverse wave

• Amplitude- the distance from either the crest or trough to the resting point of the wave

• Wavelength- distance from crest to crest or trough to trough on a wave

Wave Frequency• Frequency is a property of a wave, not a

part of one.

• Frequency is the number of waves which pass a given point in 1 second.

• Hertz (Hz) is the SI unit for frequency.

1 Hz = 1 wave passing a given point in

1 second

Compressional Waves A compressional wave vibrates in the

direction that the wave is travelling. These waves are also known as longitudinal waves.

Examples: slinky, sound waves

• The 2 main parts of a compressional wave are:A. Compression- area of higher density

within the wave

B. Rarefaction- area of lower density

within the wave

I can: Describe how sound waves are created

Do Now: Compare and contrast the two waves in terms of their amplitude, wavelength, and frequency

Amplitude –height of wave

Wavelength –length of wave from crest to crest or trough to trough

Frequency –how many waves pass per second

Sound Waves

Sound waves type of compressional wave requires a medium material through which

a wave transfers energy.Caused by vibration of particlesSound waves travel at about 750 mi/h or

335 m/s it depend on the medium

Velocity = Frequency x Wavelength

• If a sound wave (335 m/s) has a frequency

of 67 Hz, what is its wavelength?

Velocity = Frequency x Wavelength

so

Wavelength = Velocity / Frequency

= 335 m/s / 67 Hz

= 5 m

Light waves• They are transverse waves• Travel about 300 million meters per second or

186,000 miles per second• Also called electromagnetic waves• Light consists waves of different wavelengths

– These create the colors of the rainbow

The colours of the rainbow:

• Red• Orang

e• Yellow• Green• Blue• Indigo• Violet

Seeing colour• The colour an object appears depends on the colours

of light it reflects.

For example, a red book only reflects red light:

White

lightOnly red light is reflected

Reflection and Refraction• Reflection is where a wave strikes an object and

bounces off.

The Law of Reflection

• The law of reflection states that the angle of incidence is equal to the angle of reflection on a flat reflective surface.

Examples of the Law of Reflection:

Refraction is the bending of a wave as it enters a different medium, due to a change in speed.

• Because of light refraction, a person bow fishing would not aim directly at the fish. Where should they aim? Hmmmm………..

Diffraction• Diffraction is the bending of a wave, around a

barrier.