"Application of Sound Phenomenon in Science and Technology" Sound Phenomenon PPT Courseware 4

Description

"Application of Sound Phenomenon in Science and Technology" Sound Phenomenon PPT Courseware 4

Self-study text and answer questions

1. What is the frequency range of sound waves?

10-4～1012Hz

2. What is the frequency range of sound heard by normal human ears?

20～20000Hz

3. What is the highest frequency of sound that a dog can hear?

50000Hz

4. What is ultrasound?

Sound with a frequency higher than 20000Hz is called ultrasound

5. What is infrasound?

Sounds with frequencies below 20Hz are called infrasound

6. Do you know what applications ultrasound has?

Lithotripsy, B-ultrasound, sonar positioning, ultrasonic navigation

7. Do you know the dangers of infrasound?

Harmful to machinery, buildings and human body

Class summary

1. The frequency range of sound heard by the human ear: 20 ~ 20000Hz

2. Ultrasound and infrasound

Sound with a frequency higher than 20000Hz is called ultrasound;

Sounds with frequencies below 20Hz are called infrasound.

3. Application of ultrasound:

Lithotripsy, B-ultrasound, sonar positioning, ultrasonic navigation, etc.

4. Harm of infrasound:

It is harmful to machinery, buildings and human body.

1. The reason why people cannot hear the sound of flying bats is ( )

A bat makes no sound B bat makes sound too frequently

C The frequency of the bat's sound is too low D The loudness of the bat's sound is too low

Frequency and loudness only affect the pitch and size of the sound. People cannot hear the sound because the frequency exceeds the human hearing range. The answer is B

2. The wings of insects vibrate when they fly. When insect A flies, its wings vibrate 200 times per second. When insect B flies, its wings vibrate 40 times per second. A person with normal hearing can hear the insect that makes a sound when flying. ( )

A insect B insect B

C can hear it, D can't hear it

This question tests the human hearing range. Frequencies A and B are both within the human hearing range, so they can both be heard.

3. Ultrasonic radar, also called sonar, can be used to detect the depth of the ocean. How does it work during detection?

Answer: You need to first know the propagation speed of ultrasonic waves in water, represented by v. You need to measure the time t from the sound on the sea surface to the bottom of the sea and back, then you can know the depth from the sea surface to the bottom of the sea. For example: the propagation speed of ultrasonic waves in seawater is 1500m/s, the time from when the ultrasonic wave is emitted on the sea surface to when the echo is received is 4s, and the sea depth is S=1/2vt=1/2×1500m/s×4s=3000m

4. There are flies and butterflies flying around you. Why can you only detect flies but not butterflies by hearing?

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For more information about the PPT courseware "Sound Phenomenon and the Application of Sound Phenomenon in Science and Technology", please click on the Sound Phenomenon PPT and the Application of Sound Phenomenon in Science and Technology PPT tag.

"Application of Sound Phenomenon in Science and Technology" Sound Phenomenon PPT Courseware 3:

"Application of Acoustic Phenomenon in Science and Technology" Acoustic Phenomenon PPT Courseware 3 Knowledge Review 1. The frequency range heard by the human ear is _______ Hertz to _________ Hertz. 2. Sound waves greater than 20,000 Hz are called __________ 3. Sound waves less than 20 Hz are called __________ ultrasonic waves..

"Application of Sound Phenomenon in Science and Technology" Sound Phenomenon PPT Courseware 2:

"Application of Acoustic Phenomenon in Technology" Acoustic Phenomenon PPT Courseware 2 Ultrasonic bats fly at night and can also catch moths and mosquitoes. In any case, they have never seen it collide with anything, even a very thin wire. It also dodges deftly. Interesting inquiry...

"Application of Sound Phenomenon in Science and Technology" Sound Phenomenon PPT courseware:

"Application of Sound Phenomenon in Science and Technology" Sound Phenomenon PPT Courseware [Experience] Try it out and listen Activity: Take a cylindrical food can as shown in the picture, make a round hole at one end and remove the bottom surface from the other end, cover it with a rubber film and use a rubber band truss. Light the candle on the table and the candle flame no longer...

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Update Time: 2024-11-17

This template belongs to Physics courseware Beijing Normal University eighth grade physics volume one industry PPT template

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