Focus : Waves

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# Focus : Waves - PowerPoint PPT Presentation

Focus : Waves Objective: Explain what transverse and longitudinal waves are, how they are alike and how they are different. We will b e able to say how they occur in earthquakes. Vocabulary to Know. Examples: In the Ocean In the Clouds Earthquake. Sound waves are longitudinal.

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Presentation Transcript
Focus: Waves

Objective: Explain what transverse and longitudinal waves are, how they are alike and how they are different. We will be able to say how they occur in earthquakes.

Vocabulary to Know

Examples:

In the Ocean In the Clouds Earthquake

Sound waves are longitudinal.

Longitudinal waves

Transverse waves

• When an earthquake happens, energy waves vibrates through the earth’s crust as the crust bends or breaks.
During an earthquake, there are both:
• Transverse waves
• Longitudinal waves
Which wave travels faster?

Think-Pair-Share:

• Let’s find out!
• Human wave activity

Since the energy is traveling the fastest way it can (in a straight line), the longitudinal wave is faster than the transverse wave. It gets from the force to the stopping point first. It is the first wave you feel in an earthquake.

The transverse wave takes more time and energy to go perpendicular to the direction of the wave. You feel this wave second in an earthquake. It is sometimes called the “aftershock”.

Which wave does more damage?

Think-Pair-Share:

• Which wave do you think would do more damage to a city? Write this as a hypothesis. (“I think…because…”
• Why do you think so?
• Let’s find out!
• Human wave activity with buildings
What are the parts of a wave?

Transverse wave

**WRITE THIS DOWN**

The crest is the highest point on a transverse wave. The trough is the lowest point on a transverse wave.

The rest position of the wave is called the node or nodal line.

What are the parts of a wave?

Transverse wave

**WRITE THIS DOWN**

The wavelength is the distance from one point on the wave to the same point on the next wave.

On a compressional wave the (**WRITE THIS DOWN**) area squeezed together is called the compression. The areas spread out are called the rarefaction.

(**WRITE THIS DOWN**)The wavelength is the distance from the center of one compression to the center of the next compression.

Compressional

Longitudinal wave

**WRITE THIS DOWN**

The amplitude of a transverse wave is determined by the height of the crest or depth of the trough

**WRITE THIS DOWN**

How high does it go?

How low does it go?

What is wavelength? (**WRITE IT DOWN**)

Wavelength is a measure of distance, so the units for wavelength are always distance units, such as meter, centimeters, millimeters, etc.

What is wave frequency?

Frequency is the number of waves that pass through a point in one second. The unit for frequency is waves per second or Hertz (Hz). One Hz = One wave per second. (**WRITE THAT DOWN**)

The smaller the wavelength, the more times it will pass through a point in one second. The larger the wavelength, the fewer times it will pass through a point in one second.

Focus: Waves

Objective: Compare the properties of waves to the wavelike property of energy in earthquakes, light and sound.

EQ:What are the 2 kinds of mechanical waves? How are they similar? How are they different?

### WAVES

Vocabulary to Know

Examples:

In the Ocean In the Clouds Earthquake

Sound waves are longitudinal.

Longitudinal waves

Transverse waves

• When an earthquake happens, energy waves vibrates through the earth’s crust as the crust bends or breaks.
During an earthquake, there are both:
• Transverse waves
• Longitudinal waves
Which wave travels faster?

Think-Pair-Share:

• Let’s find out!
• Human wave activity

Since the energy is traveling the fastest way it can (in a straight line), the longitudinal wave is faster than the transverse wave. It gets from the force to the stopping point first. It is the first wave you feel in an earthquake.

The transverse wave takes more time and energy to go perpendicular to the direction of the wave. You feel this wave second in an earthquake. It is sometimes called the “aftershock”.

Which wave does more damage?

Think-Pair-Share:

• Which wave do you think would do more damage to a city?
• Why do you think so?
• Let’s find out!
• Human wave activity with buildings
What are the parts of a wave?

Transverse wave

The crest is the highest point on a transverse wave. The trough is the lowest point on a transverse wave.

The rest position of the wave is called the node or nodal line.

What are the parts of a wave?

Transverse wave

The wavelength is the distance from one point on the wave to the same point on the next wave.

Compressional

Longitudinal wave

On a compressional wave the area squeezed together is called the compression. The areas spread out are called the rarefaction.

The wavelength is the distance from the center of one compression to the center of the next compression.

The amplitude of a transverse wave is determined by the height of the crest or depth of the trough
Vocabulary to Know

How high does it go?

How low does it go?

What is wavelength?

Wavelength is a measure of distance, so the units for wavelength are always distance units, such as meter, centimeters, millimeters, etc.

What is wave frequency?

Frequency is the number of waves that pass through a point in one second. The unit for frequency is waves per second or Hertz (Hz). One Hz = One wave per second.

Wavelength and frequency are inversely related.

The smaller the wavelength, the more times it will pass through a point in one second. The larger the wavelength, the fewer times it will pass through a point in one second.

Vocabulary to Know

3

3

How many crests?

How many troughs?

http://id.mind.net/~zona/mstm/physics/waves/introduction/introductionWaves.html

### Waves have measurable properties

Frequency is the number of waves (vibrations) that pass through a point in one second.

Period is the time it takes for one full wavelength to pass a certain point.

Frequency is waves per second.

Period is seconds per wave.

A wave moving through a medium travels at a certain speed. This is Wave Speed.

Wave speed is usually measured in meters/second, but may be measured using other distance units (such as centimeters per second).

How is Wave Speed calculated?

Wave speed is calculated as the product of a waves frequency and wavelength.

Wavelength is represented by the Greek letter lambda (λ) and frequency is represented by (f)

Vocabulary to Know

3

3

How many crests?

How many troughs?

http://id.mind.net/~zona/mstm/physics/waves/introduction/introductionWaves.html

### Waves have measurable properties

Frequency is the number of waves (vibrations) that pass through a point in one second.

Period is the time it takes for one full wavelength to pass a certain point.

Frequency is waves per second.

Period is seconds per wave.

A wave moving through a medium travels at a certain speed. This is Wave Speed.

Wave speed is usually measured in meters/second, but may be measured using other distance units (such as centimeters per second).

How is Wave Speed calculated?

Wave speed is calculated as the product of a waves frequency and wavelength.

Wavelength is represented by the Greek letter lambda (λ) and frequency is represented by (f)