"Characteristics of Sound" Sound Phenomenon PPT Courseware 3

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"Characteristics of Sound" Sound Phenomenon PPT Courseware 3

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1. How is sound produced?

2. What is the speed of sound propagating in the air? Is it a fixed value?

3. What is echo?

Think: Listen to the voices of children and old people, do you hear anything?

Children's voices should be "thin".

The old man's voice is a bit "rougher".

Why do some sounds sound high and others sound low?

1. Pitch - The pitch of a sound is called pitch.

Demo

Press a steel ruler firmly on the table with one end sticking out of the edge of the table. Turn the steel ruler and listen to the sound it makes when it vibrates. At the same time, pay attention to how fast the steel ruler vibrates. Change the length of the steel ruler extending from the edge of the table and move it again. Pay attention to make the two vibrations of the steel ruler roughly the same.

Compare the speed of vibration and the pitch of the sound produced by the steel ruler in the two situations.

Read pages 32-33 of the textbook and answer the questions:

1. What is the physical meaning of frequency? What is frequency?

2. In the SI unit, what is the unit of frequency?

3． What is the relationship between the speed, frequency and pitch of an object's vibration?

4. What is the frequency range that most people can hear?

5. What is ultrasound? What are infrasound waves?

1. Frequency: It is a physical quantity used to describe how fast an object vibrates. (significance)

In physics, the number of times an object vibrates per second is called frequency. (definition)

2. In the International System of Units, the unit of frequency is Hertz, symbol: Hz

3． Experiments show that frequency determines the pitch of sound: an object vibrates quickly—high frequency—high pitch;

Objects vibrate slowly—low frequency—low pitch.

4. The frequency range that most people can hear: 20 Hz ~ 20,000 Hz (the most sensitive frequency is 3,000 Hz; the hearing of the elderly will decline; 20 Hz is the lower limit of hearing ~ 20,000 Hz is the upper limit of hearing)

5. Ultrasound: Sound above 20,000 Hz. Infrasound: Sound below 20 Hz. (These two sounds cannot be heard by humans)

2. Loudness - The intensity of sound is called loudness.

Ask a question What factors are related to loudness?

Design and conduct experiments

Touch a ping pong ball tied to a string to a tuning fork that is making a sound and observe how far the ball bounces.

Repeat the experiment above by making the tuning fork sound at different loudnesses.

Amplitude: How much an object vibrates.

The greater the amplitude of the sound emitter, the louder the sound produced.

It can be seen that loudness is related to the amplitude and distance of the sound emitter.

Consolidation exercises

1. "I can't sing such a high note" or "I can't sing such a low note", the "high" and "low" here refer to ______; and in "sing loudly" and "whisper softly" The "high" and "low" refer to ______.

2. Take a piece of cardboard and draw it across the teeth of the wooden comb, first faster and then slower. When you draw faster, the pitch of the sound will be ______, which shows that the pitch is related to the _____________ of the sound emitter.

3. The male student’s voice is “low”, which refers to the male student’s low voice. This is because when the male student speaks, his voice is low.

The reason for bringing ＿＿＿＿.

4. People can judge the location of sound sources by hearing. Which of the following statements is correct ( )

A. Determined by bone conduction B. Determined by the pitch of the sound source

C. Judging by the binaural effect D. Judging by the loudness of the sound source

5. “The sound of the drum needs a heavy hammer.” Please explain the meaning of this sentence from a physical perspective.

6. The depth of the ocean can be measured using ultrasonic waves. It is known that the propagation speed of sound waves in seawater is 1500m/s. If the ship sends a signal and receives a reflected wave on the sea surface 5 seconds later, what is the depth of the seabed?

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"Characteristics of Sound" Sound Phenomenon PPT Courseware 11:

"Characteristics of Sound" Acoustic Phenomenon PPT Courseware 11 Learning Objectives 1. I want to know what pitch and loudness are and be able to distinguish between them. Through exploration, I can understand the relationship between pitch and frequency, and the relationship between loudness and vibration radiation. I will initially use the control variable method to design experiments.

"Characteristics of Sound" Sound Phenomenon PPT Courseware 10:

"Characteristics of Sound" Acoustic Phenomenon PPT Courseware 10 Teaching Objectives 1. Understand the characteristics of sound 2. Know that pitch is related to the frequency of the sound emitter, and loudness is related to the amplitude of the sound emitter 3. Pay attention to the rigor of scientific terminology 4. Different sound emitters emit The timbre of the music is different from the same pitch...

"Characteristics of Sound" Sound Phenomenon PPT Courseware 9:

"Characteristics of Sound" Acoustic Phenomenon PPT Courseware 9 Learning Objectives 1. Understand the characteristics of sound; 2. Know that the pitch of sound is related to the frequency of the sound emitter; 3. Know that the loudness of sound is related to the amplitude of the sound emitter; 4. Know the different sounds The timbre of the sound produced by the body is different. Know...

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Update Time: 2024-10-03

This template belongs to Physics courseware People's Education Edition Physics for Grade 8, Volume 1 industry PPT template

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