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11/13 Quick Start

Draw a vibration.

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A vibration is a bouncing of particles that bounce off of the particles next to them that set off a chain reaction through the medium.

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11/14 Quick Start

Explain the energy transfer that causes a sound wave?

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11/15 Quick Start

How does energy affect amplitude?

Draw or write (text box)

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Agenda

Quick Start

Agenda

Announcements

Objectives/ Standards

Notes about the properties of sound

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Announcements

Sign up for Career Fair

Sign up for Skate City Field Trip

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Objectives

T: To be able to describe how changing a property of a wave will change the sound

H: How can we play instruments by altering energy?

E: Notes/ Reading on Sound

M: Complete an instrument research

A:

P: Instrument Diagram

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Standards

Objective 3

Describe the production of sound in terms of vibration of objects that create vibrations in other materials.

  1. Describe how sound is made from vibration and moves in all directions from the source in waves.
  2. Explain the relationship of the size and shape of a vibrating object to the pitch of the sound produced.
  3. Relate the volume of a sound to the amount of energy used to create the vibration of the object producing the sound.
  4. Make a musical instrument and report on how it produces sound.

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Nature of Sound

Sound waves are (mechanical) longitudinal waves.

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Sound waves are caused by vibrations - the complete back and forth motion of an particles.

  • Mechanical - needs a medium (a substance energy goes through)
  • Longitudinal - particles move parallel to wave

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Properties of Waves (Sound)

  • Amplitude - amount of energy in a wave
    • Strength of a wave
  • Wavelength - how long a wave is
    • Crest to crest or compression to compression
  • Frequency - number of waves per second
  • Speed - how fast the wave is traveling

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Label the compression and the rarefaction.

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Amplitude Investigation

Question 1: What happens if I tap lightly on your desk.

Hypothesize: Write a table group If…then…because…

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  1. Tap so lightly you can barely hear it.
  2. Observe:
    1. What are your hands doing?
    2. What are your ears doing?
    3. What patterns do you notice?

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Amplitude Investigation

Question 2: How can I make it louder?

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Hypothesize: If…then…because

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  • Try and observe
    • What are your hands doing?
    • What are your ears doing?
    • What patterns do you notice?

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What is Amplitude?

Amplitude: Loudness or softness of a sound

Loudness - how well a sound can be heard.

2 factors -

  • Amount of energy (intensity)
  • Distance - as sound spreads out you gather less of the energy so it is softer

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Decibels (dB) is the unit we use to measure amplitude of sound.

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Amount of Energy effect on Amplitude

What do we notice between the two waves?

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Distance from source effect on Amplitude

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Something to think about….

Why You should not

1)wear your earbuds too long

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2) listen to music too loud

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Humans have a range from 0 dB to 120 dB.

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Properties of Waves (Sound)

Pitch - How High/ Low a sounds seems to be

High pitch - high note Low pitch - low note

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Frequency of a wave is what determines pitch.

  • Higher Frequency = ______ pitch

Pitch is measured in Hertz. 1 HZ = 1 Wave per second

Higher

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Properties of Waves (Sound)

Frequency of a wave is what determines pitch - so by changing these two factors you can change the pitch of a sound

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2 factors that affect frequency…

Wavelength of the wave

Speed of the wave through the medium

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Pitch Investigation

Question 1: What happens if I strum the string (rubber band) with no changes?

Hypothesize: Write as a table group If…then…because…

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  • Strum and pass around the table.
  • Observe: What do you hear? What is happening to the string? Try a slo mo video.

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Pitch Investigation

Question 2: How can I change the note?

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Hypothesize: If…then…because

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  • Try and observe
    • Observe: What do you hear? What is happening to the string? Try a slo mo video.

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Changing Pitch

In order to change the pitch of a sound you must change

  • tighten/loosen the medium
    • changes how fast the wave travels
  • shorten/ lengthen the wavelength
    • changes the length of the wave and the frequency

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How do we compare?

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Think about it...

Why might different animals be able to hear different pitches?

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Write/ Think/ Share/ Summarize

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How does the ear work?

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As you watch, write 2 things you learn

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Hearing Test

Warning:

If doing this at home, use caution. Pets may not react well to the sounds.

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Other Hearing tests

Short Test

Long Test

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Be careful and do not play around with these. You can inflict pain and damage to people.

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Do you see/hear evidence of the frequency changing?

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Do you see/hear evidence of the amplitude changing?

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Instrument Activity

Using the instruments at your table

Observe

  • Which is higher and lower. Why?
  • What else can you observe?

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Challenge:

  • How can you change the amplitude? How can you measure that?

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  • How can you change the wavelength? How can you measure that?

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  • How can you change the frequency? How can you measure that?

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Review 1:

Amplitude helps us to determine _________

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Review 2:

Frequency helps us to determine _________

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