"Characteristics of Sound" The World of Sound PPT Courseware

Description

"Characteristics of Sound" The World of Sound PPT Courseware

Noise Irregular, unpleasant and harsh sounds

Musical sound is a regular, pleasant sound

Characteristics of musical sounds

Loudness, pitch and timbre

1. Loudness

1. Loudness: refers to the strength of the sound

The loudness of a sound is related to the amplitude of the vibration of the sounding object:

The greater the amplitude of vibration, the louder the sound;

The smaller the amplitude of vibration, the smaller the loudness of the sound;

2. Amplitude: the maximum distance of a vibrating object from its original position.

2. Tone

1. Pitch: refers to the pitch of the sound.

2. Frequency: the number of vibrations in 1 second.

Pitch is related to the frequency at which the sound emitter vibrates:

The greater the vibration frequency, the higher the pitch;

The smaller the vibration frequency, the lower the pitch.

3. Tone

The characteristics of sound, different sound emitters have different timbres, and the timbre is determined by the sound emitter itself.

4. Noise

Noise: messy sound (physics concept). Produced by irregular vibrations of the sound emitter.

From an environmental protection point of view, any sound that hinders people's normal rest, study and work, as well as any sound that interferes with the sounds that people want to listen to, is noise.

(For example: the sound of cars, voices in a quiet library, the sound of machines at a construction site, neighbors’ loud music, etc.)

Noise levels and hazards

1. People use decibels to classify sound intensity levels, and the symbol of decibels is dB.

2.0dB is the weakest sound that people can hear just now - the lower limit of hearing

3. To protect hearing, the noise should be controlled not to exceed 90dB; to ensure work and study, the noise should be controlled not to exceed 70dB; to ensure rest and sleep, the noise should be controlled not to exceed 50dB.

Noise control

There are three stages from sound generation to hearing:

The sound source produces sound ---- propagates through media such as air ---- the eardrum vibrates

Methods to reduce noise: noise reduction, sound insulation, and sound absorption. The most fundamental of these is to eliminate or reduce the noise from the sound source.

summary

1. Loudness

1. Loudness: the strength of the sound

2. Amplitude: the maximum distance of a vibrating object from its original position.

3. The relationship between loudness and amplitude:

2. Tone

1. Pitch: the pitch of the sound

2. Frequency: the number of vibrations in 1 second.

3. The relationship between pitch and frequency:

3. Timbre 1. Timbre: the characteristics of the sound.

2. Determining factor: determined by the sound emitter itself.

4. Methods to control noise

1. Attenuate at the sound source

2. Weakened during the propagation process

3. Weakened at the human ear

Consolidation exercises

1. Which of the following statements is correct ( )

A. The "high" in "寭声高歌" refers to a high pitch.

B. The "soft" in "whisper" refers to the low pitch.

C. The "sharp" in "sharp voice" refers to the high pitch.

D. The "high" in "The attack is too high to go up" refers to the loudness.

2. In the following sentences related to sound, the physical meaning expressed is

① "Deafening" means that the sound is _______ loud.

②The "low" in "whisper" refers to the _______ of the voice.

③The child's words are "as crisp as a silver bell", which means his voice is _______ high

④ "Pleasant to the ear" means that the sound is _______ good.

3. When a bee flies with nectar, its wings vibrate an average of 300 times per second, and when flying without flowers, its wings vibrate an average of 440 times per second. An experienced beekeeper can identify when a bee flies out to collect nectar. I collected honey and flew back to the hive to try to explain this phenomenon.

4. Which of the following statements about noise is wrong ( )

A. The pleasant music may be noise;

B. Noise is emitted when the machine vibrates during operation;

C. Noise harms people’s physical and mental health;

D. Sounds that interfere with the sounds people want to hear are noises.

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Update Time: 2024-11-26

This template belongs to Physics courseware Shanghai Science Edition 8th Grade Physics industry PPT template

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