"Hazards and Control of Noise" PPT teaching courseware on acoustic phenomena

"Hazards and Control of Noise" PPT teaching courseware on acoustic phenomena

Part One Content: Basic Knowledge Key Points

Knowledge point 1: Source of noise

1. We live in a world of sound, and sound is everywhere. The following sounds: ① The roar of machines in the factory workshop; ② The sound of Peking Opera performances in the theater; ③ The chirping of birds in the park in the early morning; ④ The sound of electric drills during house decoration; ⑤ The sound of students reading loudly in the classroom; ⑥ Mountains The sound of gurgling water in the creek. Among them, those that belong to noise are ①④ (fill in the serial number).

2. As shown in the figure are the waveforms of four sounds, among which the noise waveform is (D)

Knowledge point 2: Noise intensity levels and noise hazards

3. After experiments, the sound intensity that affects people’s work efficiency is (C)

A. Below 40 dB B. 40~70 dB

C. Above 70 dB D. 90 dB

4. Noise seriously pollutes the human environment and is listed as an international public nuisance. Which of the following statements is wrong (B)

A. Noise hinders people’s lives

B.Noise can cause people to be poisoned

C. Noise affects people’s work and study

D.Noise is harmful to human health

Knowledge point 3: Control noise

5. Soundproof walls are generally installed on both sides of highways close to residential areas, which reduce the noise during transmission; vehicles driving through school areas are prohibited from honking their horns at the source of the sound (please fill in "Sound Source" for both "During the propagation process" or "at the human ear") to reduce noise.

6. Which of the following measures reduces noise at the place where the sound is generated (B)

A. Install double-glazed windows in the room

B. In order to prevent the square dance music from disturbing the public, the aunts wore wireless headphones

C. Cover your ears with your hands when setting off firecrackers

D. The interior walls of the theater are decorated with sound-absorbing materials

7. When you are reviewing your homework at home in the evening, your neighbors are singing loudly, which interferes with your study. In order to reduce the noise, among the following four measures, the most effective one is (D)

A. Plug your ears with cotton B. Negotiate with your neighbors to reduce the volume

C. Close the windows and draw thick curtains D. Open the windows to increase air flow

PPT on the harm and control of noise, part 2: improvement of comprehensive capabilities

8. We live in a sea of ​​sounds, some of which are beautiful and some of which are irritating. Noise monitors set up in bustling downtown areas measure the loudness of sounds (optional "loudness", "pitch", "timbre" or "frequency").

9. Noise monitoring equipment will be installed on the main streets of the city. As shown in Figure A, it is an electronic noise monitor. At a certain moment, the number displayed on the display screen of the device is 57.5, and the unit is decibel (or dB). When a car or motorcycle passes nearby, the number on the display will increase (optional "increase", "decrease" or "unchanged").

10. The harm of noise needs to be eliminated and reduced in our daily lives and studies. Among the following measures, the ones that eliminate noise at the sound source are ①; those that reduce noise during the propagation process are ②③ (fill in the serial numbers for both).

① There are no farmers’ markets or noisy factories near schools, hospitals and libraries.

②In some entertainment venues, sound insulation panels are installed in dance halls and singing rooms.

③Plant trees around schools and residential areas

④Staff near the aircraft wear earmuffs

11. Regarding music and noise, which of the following statements is correct (D)

A. The noise has a high pitch

B. Difference in timbre of noise

C. The sound of the music is good

D. Musical sounds can also become noise

12. In order to protect students in the classroom from environmental noise, which of the following practices is the most unreasonable (B)

A. The teacher speaks louder

B. Each student wears a noise-proof earmuff

C. Close the doors and windows

D.Plant trees around the classroom

13. There is such a joke: Person A: "The newly moved neighbor is so disgusting. Last night, in the middle of the night, in the dead of night, he suddenly came and rang my doorbell." Person B: "It is indeed disgusting! Did you call the police immediately? "A: "No, I thought they were crazy and continued to blow my trumpet." Excuse me, the real noise maker in the joke is (A)

A.A B.B

C. Neighbors D. No one makes noise

Noise hazards and control PPT, part 3: Expanding research and breakthroughs

17. Xiao Ming lives in a bustling downtown. The honking of vehicles and the cries of vendors on the street are still heard late at night, resulting in serious noise pollution. Xiao Ming wants to make a noise-proof earmuff. By comparing the sound insulation properties of several materials (clothing, tinfoil, and foam plastic), he selects a suitable material as the filler of the earmuff.

(1) In addition to the materials to be tested, the experimental equipment prepared also includes tuning forks, alarm clocks and shoe boxes, of which the alarm clock is suitable as a sound source;

(2) Xiao Ming puts the sound source into the shoe box, fills it with the filling material to be tested, and designs two experimental plans A and B. Do you think the best plan is B;

A. Stand at a certain distance from the shoe box and compare the loudness of the sounds you hear.

B. While listening to the sound, move back until the sound is no longer heard, and compare the distance from the shoe box

(3) The results obtained from the experiment are as shown in the table. Foam plastic has the best sound insulation performance among the materials to be tested.

Keywords: Free download of PPT courseware for eighth-grade physics volume 1 of the People's Education Press, PPT download on the hazards and control of noise, PPT download on acoustic phenomena, .PPT format;

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