Bellwork:

Using the sentence frame, answer the following question: What are waves? What do they do? Give five examples of waves around you.

“Waves are __________________. Waves transfer _______________. Some examples of waves around me are ______________, ______________, _____________, ______________, and _____________.”

NGSS

MS-PS4-1. Use mathematical

representations to describe a simple model for waves that includes how the amplitude of a wave is related to the

energy in a wave.

Content Objectives: Language Objectives:

Identify the different parts of a wave.

Explain how frequency, amplitude, wave speed, and wavelength all relate to the energy of the wave.

Define wave, amplitude, wavelength, wave speed, frequency, medium, trough, crest, rarefaction, and compression.

Explain how parts of the wave relate to the energy of a wave using different sentence frames.

Objectives:

Properties of Waves

Vocabulary

Waves: any disturbance that transmits energy through matter or empty space.

Amplitude: the height of the wave from its rest point.

Wavelength: the distance from any point on a wave to an identical point on the next wave.

Wave speed: the speed at which a wave travels.

Frequency: the number of waves produced in a given amount of time.

Vocabulary

Medium: a substance through which a wave can travel.

Trough: the lowest point in a transverse wave.

Crest: the highest point of a transverse wave.

Rarefaction: a part where the particles are spread apart.

Compression: a part where the particles are crowded together.

Amplitude

• What Is Amplitude? The amplitude of a wave is related to its height. A wave’s amplitude is the maximum distance that the particles of a medium vibrate from their rest position.

• Larger Amplitude—More Energy A wave with a large amplitude carries more energy than a wave with a small amplitude does.

Rest Positio

n

Amplitude: Height of the wave from rest position

Wavelength

• What Is a Wavelength? A wavelength is the distance between any two crests or compressions next to each other in a wave.

• Shorter Wavelength—More Energy A wave with a shorter wavelength carries more energy than a wave with a longer wavelength does.

Wavelength

Frequency

• What Is Frequency? The number of waves produced in a given amount of time is the frequency.

• Higher Frequency—More Energy If the amplitudes are equal, high-frequency waves carry more energy than low-frequency waves.

• Frequency is usually expressed in hertz (Hz).• 1Hz=1s

Wave Speed

• What Is Wave Speed? Wave speed is the speed at which a wave travels.

• Frequency and Wavelength Relationship Three of the basic properties of a wave are related to one another in the wave equation—wave speed, frequency, and wavelength. If you know any two of these properties of a wave, you can use the wave equation to find the third. One of the things the wave equation tells you is the relationship between frequency and wavelength. If a wave is traveling a certain speed and you double its frequency, its wavelength will be cut in half.

Wave Speed Equation

Wave speed WavelengthFrequency

Math Focus

Determine the wave speed of a wave that has a wavelength of 5 m and a frequency of 4 Hz.

Write the equation: v=λ x fReplace the λ and f with the values given in

the problem and then solve.v=5m x 4Hz= 20 m/s

Other Equations

How does the amplitude of a wave relate to the energy of a wave?

The _________ of a wave relates to the energy of a wave because

_____________________.

Be prepared to share.

How does the wavelength of a wave relate to the energy of a wave?

The _________ of a wave relates to the energy of a wave because

_____________________.

Be prepared to share.

How does the frequency of a wave relate to the energy of a wave?

The _________ of a wave relates to the energy of a wave because

_____________________.

Be prepared to share.