Unit Nine Physics

—Truth may be blamed but shall never be shamed.

Do you know?

•Trigger 扳机 Decibel 分贝 barrel枪管

•Academy Award 奥斯卡奖•Sonic 声音的 submachine gun 半

自动步枪•Hollywood 好莱坞 distraction 干

扰

How do you say it?• 音像效果 sound effect

• 电影制作人 movie producer

• 消音器 silencer

• 特务 Agent

• 噪音 noise

• 手枪 pistol/handgun/revolver

• 步枪 rifle

• 声波 sound wave

• 传导 transmit

Make up a sentence

• We might add that unregistered silencers are also highly illegal, even if they are relatively ineffective homemade creations.

Background information & additional notes

• 1. NATO: This abbreviation stands for North Atlantic Treaty Organization. NATO is an alliance of 19 countries from North America and Europe committed to fulfilling the goals of the North Atlantic Treaty signed on 4 April 1949.

• 2. silencer: a device attached to the barrel of a gun to reduce the noise of the gun shots.

• 3. On Deadly Ground(极地雄风）： An American movie produced by Warner Bros. in 1994.

• 4.HAL: an intelligent robot created by Arthur C. Clarke in his science fiction novel.

• 5. 2001: A Space Odyssey(２００１年太空漫游）： A Metro-Goldwyn-Mayer　 (MGM米高梅公司） product in 1968.

• 6. Tora Tora Tora: A 20th Century-fox product in 1970.

• 7. Pearl Harbor: A Jerry Bruckheimer product in 2001.

Learn about the text

• 1. what is the main idea of the text?

• 2. what does the description at the beginning of the text tell us?

• 3. what is muzzle blast?

• 4. what is the silencer?

• 5. what is the problem some movie makers ignored concerning sound effects?

• 6. what explanation does the author give to sound wave transmission?

• 7. what does the author say about using unregistered silencers?

• 8. when the author mentioned dramatic license, what does he want to tell us?

• 9. why is the author quite positive about the movie 2001: A Space Odyssey?

• 10. what does the author say about the viewers today?

Textual organization• Para. 2-3 are used as examples to tell the

readers that what we see in movies may not necessarily be real from a physics point of view.

• Para 4 is to give a scientific explanation of the actual situation related to the movie examples.

• Para 5 tell us that the loudness of the muzzle blast is so high that it requires precisely silencer to have it reduced.

• A scientific analysis of the sound effect is given in Para 7.

• From Para 8 the author starts to talk about the makeshift silencer in movies.

• A justification is given in Para 11 arguing that using scenes based on realistic physics may also create an dramatic result.

Exercise

• II vocabulary study

• A.

• 1. methodical 2. screwed 3. discharge

• 4. obsessed 5. simultaneously 6. distraction

• 7. transmission 8. eliminate 9. convey

• 10. authenticity 11. ridiculous

• B

• 1. commonplace 2. commonest

• 3. insure 4. secure

• 5. confined 6. restrict

• 7. distributed 8. contribute

• 9. eliminate 10. demolished

• 11. transmitted 12. transplanted

• 13. nominate 14. Candidates

Grammar review• A.

• 1. are being wasted

• 2. be repaired

• 3. has been cut off

• 4. will have been finished

• 5. being introduced

• 6. be discussed

• 7. have been invited

• 8. have met

• B

• 1. to 2. efficient 3. achieving 4. acquired

• 5. Information-based 6. encouraging

• 7. to 8. arranged 9. to be 10 paid

translation

• I. Translate the following into Chinese.

声音是一种能量的转换。我们可以用单位时间上产生的声音能量或声能来标定声音的大小；但是这仅仅描述了事情的一部分。声波向外传播就像许多气球从同一点向外飘散。声能沿着声波的表面分布，其区域随着传播距离的平方而增加。换句话说，声波单位面积上的能量随着声波远离声源而减少。无论远近传到人耳的声波区是相同的。但是当我们距声源较远时，声波区上的能量也就明显减少。所以我们听到的声音就比较小。

• II Chinese- English

Cutting sound intensity in half only reduces the relative loudness by merely 3 dB. This would be barely noticeable. A good set of ear plugs typically reduces noise by about 30 dB and so, would reduce a muzzle blast from 150 to 120 dB, a whopping noise reduction of 100 dB from the dB level of a muzzle blast! In other words, a silencer has to reduce sound intensity of a muzzle blast by a factor of 1010 to give such a low relative loudness.

• This can be done with a very well-designed and precisely made silencer using subsonic ammunition. However, even commercially available silencers are more likely to give a reduction of 30 to 40 dB similar to ear plugs than the incredible 100 dB reduction frequency portrayed in movie.