"The Generation and Propagation of Sound" Sound Phenomenon PPT Courseware 2

Description

"The Generation and Propagation of Sound" Sound Phenomenon PPT Courseware 2

Objectives of this section

1. The production of sound

2. Propagation of sound

(1) Form of sound transmission

(2) Substances that transmit sound

3. Speed ​​of sound

(1) Factors affecting the speed of sound

(2) Common sound speed

(3) Echo ranging

New lesson preview

1. Sound is produced by the sound-emitting body _____. When the vibration stops, the sound will be _____.

2. When the artillery is fired, the glass windows of nearby houses will make sounds. This is caused by the glass ________.

3. In windy weather, the wires erected on the roadside will buzz. This sound is caused by the wires ________

4. The sound produced by the plucked strings relies on the _____ of the strings. When the drum sounds, press the drum head with your hand and the drum sound will disappear. This is because the drum head stops _____.

1. Don’t make loud noises when fishing, because fish will be scared away when they hear human voices. This means ( )

A. Only air can carry sound

B. Both air and water can carry sound

C. The speed of sound in water is slower than the speed in air

D． When sound passes from air to water, its pitch changes

2. When sound is transmitted from air to water, its propagation speed will be: ( ).

A. become bigger; B. become smaller;

C. unchanged; D. Can not be sure.

Introduction of new courses

Small experiment:

1. Touch your throat with your hands and experience the feeling of your hands when speaking. Do you still feel this way after you stop talking?

2. Strike the tuning fork, then put the tuning fork into the water and observe the water phenomenon.

3. If you press and hold the sounding tuning fork, will the tuning fork still make sound?

1. The production of sound

1. The production of sound

Sound is produced by vibrations of objects.

All objects that make sound are vibrating, and when the vibration stops, the sound will stop.

2. Sound source: the object that is making sound.

The sound produced by percussion instruments is produced by _________vibration.

The sound produced by stringed instruments is produced by ___________ vibrations.

The sound produced by wind instruments is caused by the vibration of ___________.

classic experiment

Experimental method: conversion method

(A method of converting physical phenomena that are difficult to observe into physical phenomena that are easily observed)

For example, if you place a glass of water on the table and tap it, you will see ripples on the water surface, indicating that the tabletop is vibrating.

(Convert unobservable tabletop vibrations into easily observable ripples on the water surface.)

The students can hear the teacher's speech, and the sound is transmitted to everyone's ears through _______.

If not can you still hear the sound?

Vacuum bell experiment:

in conclusion:

The propagation of sound requires a medium

Sound cannot be transmitted in a vacuum

3. Speed ​​of sound

Thinking: In order to hear the sound of a train in the distance, people choose to lie on the rails (solid) and listen instead of listening directly (air). Explain that sound propagates at different speeds in different media. It propagates ____ (faster, slower) in solids than in gases.

Information obtained from the table:

1. There are two factors that affect the speed of sound propagation:

(1) Type of medium (the propagation speed of sound in different media is generally different)

(2) Temperature (the same medium generally has different propagation speeds at different temperatures)

2. Under normal circumstances, solids transmit sound the fastest, followed by liquids, and gases the slowest.

That is: v solid > v liquid > v gas

3. The commonly referred to as the speed of sound refers to: the speed of sound in the air at 15°C - 340m/s.

Echo phenomenon: The phenomenon in which sound is reflected back after encountering obstacles during propagation.

After sound is reflected, the speed of sound remains unchanged.

The time it takes for a person to distinguish between the original sound and the echo is 0.1s, so to distinguish the echo, the obstacle must be _____m away from the person

2. When ringing the big bell, we will find that after stopping the impact on the big bell, the big bell will still "remaining sound". The main reason is: ()

A. "Resounding sound" is the echo of the bell we hear

B. The big clock is still vibrating

C. The clock stops vibrating, but the air is still vibrating.

D. Human hearing is "prolonged"

Keywords: Acoustic phenomenon teaching courseware, sound generation and propagation teaching courseware, People's Education Edition eighth grade physics PPT courseware download, eighth grade physics slide courseware download, acoustic phenomenon PPT courseware download, sound generation and propagation PPT courseware download, .PPT format;

For more information about the "Acoustic Phenomena: The Generation and Spread of Sound" PPT courseware, please click on the "Acoustic Phenomenon ppt: The Generation and Spread of Sound ppt" tag.

"The Generation and Propagation of Sound" Sound Phenomenon PPT Courseware 15:

"Generation and Propagation of Sound" Acoustic Phenomenon PPT Courseware 15 Learning Objectives 1. Through observation and experiment, initially understand the conditions for sound generation 2. Know that sound is produced by the vibration of objects 3. Understand the concept of sound source 4. Through observation and experiment Experiment, preliminary understanding of sound propagation...

"The Generation and Propagation of Sound" Sound Phenomenon PPT Courseware 14:

"Generation and Propagation of Sound" Acoustic Phenomenon PPT Courseware 14 Learning Objectives: Preliminarily understand the conditions for the generation and propagation of sound. Know that sound is produced by the vibration of objects. The propagation of sound requires a medium, and sound propagates at different speeds in different media. I know the echo is...

"The Generation and Propagation of Sound" Sound Phenomenon PPT Courseware 13:

"The Generation and Propagation of Sound" Sound Phenomenon PPT Courseware 13 1. Explore the causes of sound? Activity: Use your existing equipment to make sounds. Think: What characteristics do objects that make sounds have in common? The common characteristics of objects making sounds are: The sound is made of...

File Info

Update Time: 2024-07-05

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

Preview