"How Do We Hear Sound" Sound and Environment PPT Courseware

Description

"How Do We Hear Sound" Sound and Environment PPT Courseware

teaching objectives

1. Know that sound is produced by the vibration of objects.

2. Know that sound propagates outward in the form of waves; know that the propagation of sound requires a medium, and different media propagate sound at different speeds.

3. Understand the process of hearing after sound waves enter the human ear.

4. Through observation and experiment, explore the conditions for sound generation and propagation

The course standard requirements for this chapter:

1. Through experiments, understand the conditions for the generation and propagation of sound.

2. Understand the characteristics of musical sounds.

3. Understand some applications of acoustic knowledge in modern technology

4. Know the dangers of noise and methods of control.

1. The production of sound

Sound is produced due to __________, the vibration stops and the sound production also stops.

We call _______________ ______.

Discuss

What objects can be sources of sound?

Solids, liquids and gases can all be sources of sound.

2. The essence of sound is a wave, which we call _______.

The drum vibrates to the left and thins the air on the right.

The drum vibrates to the right, compressing the air on the right; making this part of the air denser;

The drum surface vibrates left and right, forming sparse and dense sound waves in the air, which spread out from near to far.

Sound waves can make other objects vibrate

3. Sound propagation conditions

What conditions are needed for the propagation of sound?

The sounds we usually hear come through the air.

So, can liquids and solids transmit sound?

in conclusion

1. Sound can spread in: ______, _______, _______.

2. Sound ______ (fill in “can” or “cannot”) propagate in a vacuum.

3. Sound transmission needs:_______________

4. Conditions for sound generation and propagation:

①______________

②______________

Sound travels at different speeds in different materials.

Generally speaking, V solid>V liquid>V gas.

The speed of sound propagation is not only related to the sound-transmitting material, but also related to the surrounding temperature.

Speed ​​of sound: How fast sound travels. V=S/t

The speed of sound depends on the medium. The fastest among solids (about 5000m/s among steel and iron)

Slower in liquid (about 1500m/s in water)

Slowest in air (340m/s at 15°C)

The speed of sound in air increases with temperature: for every 1°C increase, the speed increases by 0.6 m/s.

Practice in class:

Someone shouted at the mountain, and it took 2.5 seconds before he heard the echo. He was about ( ) meters away from the mountain.

An iron pipe more than 1,000 meters long is closed at both ends and filled with water in the middle. Person A knocks on the iron pipe at one end. Person B can hear ( ) sounds at the other end. He first hears ( ), then hears ( ) and finally hears from Sounds in the air.

Operation:

Classwork: pages 1, 2, 3, 4, 5, 6 on p29.

Extracurricular homework: Complete basic training and check by team leader.

Tutorial (preview): a. What are the pitches of sounds called? What is frequency? What is the relationship between frequency and pitch? Compare waveforms of different frequencies; b. What are the factors that affect the tone of stringed instruments? What is ultrasound? What is infrasound?. The team leader checks the preview status.

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For more information about the PPT courseware "Sound and Environment How Do We Hear Sound", please click the Sound and Environment ppt How Do We Hear Sound ppt tag.

"How We Hear Sound" Sound and Environment PPT Courseware 2:

"How We Hear Sound" Sound and Environment PPT Courseware 2 Learning Objectives 1. Know that sound is produced by the vibration of objects. 2. Know that sound propagates outward in the form of waves, that sound propagation requires a medium, and that sound propagates at different speeds in different media. 3...

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Update Time: 2024-11-19

This template belongs to Physics courseware Guangdong and Shanghai version of eighth grade physics volume one industry PPT template

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