"Characteristics of Sound" Sound Phenomenon PPT Download

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"Characteristics of Sound" Sound Phenomenon PPT Download

The first part: sorting out new knowledge

One tone

1. Definition: In physics, the _______ of sound is called pitch.

2. Factors that determine pitch

(1) As shown in Figure 2-2-1, the experiment shows that the pitch is related to the _______ of the sound source vibration. In physics, ______ is used to describe how fast a sound source vibrates.

(2) The frequency of sound refers to the number of times the sound source vibrates within _______. The unit is _______, referred to as _______, and the symbol is _______.

(3) The higher the frequency of the sound, the _______ the pitch; the lower the frequency, the _______ the pitch.

3. Waveform diagram: Sounds with different tones can be distinguished by the waveform diagram of the sound. Figure 2-2-2 shows the waveform diagram of the sound emitted by two different tuning forks A and B. The frequency of A is _______, and the frequency of the sound is _______. tone_______. (Please fill in "High" or "Low")

4. Ultrasound and infrasound waves

(1) Most people can only hear sounds in the frequency range of ______~______Hz, and sounds below and above this frequency range cannot be heard.

(2) Ultrasound: sound higher than ______Hz.

(3) Infrasound: Sound lower than ______Hz.

2. Loudness

1. Definition: In physics, the ______ of sound is called loudness.

2. Factors that determine loudness

(1) As shown in Figure 2-2-3, the experiment shows that the loudness of the sound is related to the ______ of the vibration of the sounding body. In physics, ______ is used to describe the amplitude of an object's vibration.

(2) The larger the amplitude, the louder the sound is______; the smaller the amplitude, the louder the sound is______.

(3) Whether the sound heard by a person is loud or not is not only related to the loudness of the sound emitted by the sound emitter, but also related to the distance of the person from the sound emitter. Sound spreads in all directions from the sound source, and becomes more dispersed as it goes farther away. Therefore, the further away from the sound source, the smaller the sound you hear.

3. Waveform diagram: Sounds with different loudness can be distinguished by the waveform diagram of the sound, as shown in Figure 2-2-4. In waveform diagram B, the amplitude ______ and the loudness of the sound ______. (Choose “big” or “small” for both)

Three timbres

1. Definition: Timbre is the quality of sound and is the basis for distinguishing sound emitters.

2. Factors that determine timbre: timbre is determined by factors such as ______ and ______ of the sounding body.

Characteristics of sound PPT, part 2: application examples

Type 1 Pitch and its influencing factors

Example 1 (Multiple choice) As shown in Figure 2-2-6, it is an experimental device for "exploring the factors that affect the pitch". Which of the following statements is correct ()

A． Change the frequency of vibration of the steel ruler by changing the length of the steel ruler extending from the table

B. In multiple experiments, the amplitude of the steel ruler vibration was kept the same, and the control variable method was used.

C. The longer the steel ruler extends out of the table, the faster it vibrates.

D. Objects vibrate quickly and at high frequency, producing high-pitched sounds.

[Analysis]When exploring the relationship between pitch and frequency, use the control variable method and control the amplitude to be the same. In the experiment, the frequency of vibration of the steel ruler was changed by changing the length of the steel ruler extending out of the table. The longer the steel ruler extends out of the table, the slower the vibration, the lower the frequency, and the lower the pitch of the sound it emits; the shorter the steel ruler extends out of the table, the faster the vibration, the higher the frequency, and the higher the pitch of the sound it emits.

[Method Guidance] Use the control variable method to explore the relationship between pitch and frequency

When several factors affect the research results at the same time, other factors should be controlled unchanged and the impact of one factor on the results should be explored at a time. For example, in this experiment, the amplitude of each vibration of the steel ruler is roughly the same, and the relationship between the pitch and the speed (frequency) of the object's vibration is explored. This method of studying the problem is called the controlled variable method.

Type 2 Loudness and its influencing factors

Example 2 As shown in Figure 2-2-7, in the experiment of "exploring the factors that affect the loudness of sound", if you hit the drum with different forces, you will hear the _________ of the drum sound change, and at the same time, the______ of the drum surface will change. _______ will also change, leading to the conclusion: ____________________. In the experiment, the purpose of sprinkling some paper scraps on the drum surface is to ____________________________. This method of studying the problem is called ________ (optional "control variable method" or "conversion method").

[Method Guidance]Use the conversion method to explore the vibration of sound emitters

Since it is not easy for the human eye to directly observe the vibration of some sound emitters, other objects can be used to display it during exploration. Even if the sound emitter comes into contact with light and small objects, the vibration of the sound emitter will be "amplified" into the movement of light and small objects for easy observation. . This method of studying a problem is called the conversion method.

Type 3: Discrimination of pitch and loudness

Example 3: The following description of the conversation between the bee and the old cow is correct ()

A. The sound made by bees when flying is high-pitched, and the cry of cows is loud.

B. Bees make low-pitched sounds when they fly, and cows make low-pitched calls.

C. Bees make low-pitched sounds when they fly, and cows make louder calls.

D. Bees make louder sounds when they fly, and cows make lower noises.

[ Analysis But the amplitude is small, so the sound emitted by the bee when flying is high-pitched and low-loud.

[Error-prone analysis] (1) A high-pitched sound is not necessarily loud, and a loud sound is not necessarily high-pitched. In physics, pitch is discussed as "high or low" and loudness is discussed as "large or small".

(2) In daily language, the high and low sounds sometimes refer to the pitch, and sometimes refer to the loudness. For example, if the voice is not "high", this "high" refers to the loudness, and for female "treble" singers, this "high" refers to the pitch.

(3) The pitch depends on the frequency of the object's vibration. The higher the frequency, the higher the pitch. The frequency of the vibration of an object depends on the length, thickness, tightness, etc. of the vibrating object. The shorter, thinner, and tighter the vibrating object, the higher the vibration frequency and the higher the pitch of the sound.

Type 4: Tone and its applications

Example 4: There is a kind of "bank" that specializes in storing valuables. After people store their valuables, they need to use instruments to record their "handprints", "eyeprints", "voiceprints", etc., so that they can use these unique items in the future. Features: Take items in person to prevent others from taking them away. The "voiceprint" here records what people say when they speak ()

A． Tone b. loudness

C. Timbre D. All three

Characteristics of Sound PPT, Part 3: Class Feedback

1. As shown in Figure 6-1, press a steel ruler firmly on the table, extend one end of it from the edge of the table, stir the steel ruler, and listen to the sound it makes when it vibrates. Change the length of the steel ruler extending from the edge of the table, and push it hard again to make the two vibrations of the steel ruler roughly the same, and listen to the change in the sound it makes. This experiment is used to explore ()

A． Can sound propagate through solids?

B. The relationship between loudness and object amplitude

C. The relationship between pitch and vibration frequency of objects

D. What factors of the sounding body are related to the timbre?

2. When exploring what factors are related to loudness, Xiaoli conducted the following experiments, as shown in Figure 6-2.

(1) When the tuning fork is struck with different forces, so that the tuning fork emits sounds of different loudness, the ping pong ball is bounced to different amplitudes, and the tuning fork vibrates with different amplitudes, indicating that the loudness is related to _______. The greater the bounce of the ping pong ball, the ______ the amplitude and loudness of the tuning fork.

(2) Make the tuning fork emit the same loudness sound. When the distance is different, the loudness of the sound emitted by the tuning fork is different _____, indicating that the loudness is related to _______________.

3． When boys and girls sing in a chorus, if the baritone sings loudly and the soprano sings softly, the loudness of ________ is louder and the pitch of ________ is high.

4. The sound of the violin heard at the concert is produced by ______ of the strings. At the same time, we can also distinguish the sounds of different instruments based on the ______ of the sounds.

5. The "buzzing" sound that people hear when mosquitoes fly is produced by the mosquito's wings and is transmitted to the human ear through ________. But humans cannot hear the sound of butterflies flying because the _________ where the butterflies make sounds is not within the hearing range of human ears.

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Update Time: 2024-09-28

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