Revision_helper_U11_bilingual

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1 Part 1 Revision Helper 溫習錦囊 (Bilingual version) 雙語版本部分 Revision notes 溫習筆記 第 Chapter 1 第 章 Air Senses and burning and sight 感覺和視覺 31.1 The importance of sensing the environment 31.1 探測環境刺激的重要性 Q1 How can we detect different stimuli? 我們如何探測不同的刺激? A1 We can detect different stimuli with five sense organs: the eyes, ears, nose, tongue and skin. Each kind of sense organ has its own receptors. When the receptors detect a stimulus, they send messages to the brain through nerves to produce senses. The following shows the process of how a sense is produced. 我們具有五種感覺器官, 包括眼睛 耳朵 鼻子 舌頭和皮膚, 來探測不同的刺激刺激 每種感覺器官都各有特別的感受器感受器來探測不同的刺激 當感受器探測到刺激時, 會發出訊息, 訊息沿神經神經傳送到腦, 從而產生感覺感覺 以下顯示感覺產生的過程 stimulus 刺激 detected by 被探測 receptors of a sense organ 感覺器官的感受器 send messages through nerve to 把訊息沿神經送到 brain 腦 produces 產生 sense 感覺 1

2 Q2 A2 What kind of stimuli can be detected by our sense organs and what senses will be produced? 我們的感覺器官可以探測到哪 些刺激? 又會產生哪些感覺? The following table summarises the stimuli detected by our sense organs and the corresponding senses produced. 下表顯示我們的感覺器官, 以及探 測到的刺激和所產生的感覺 Sense organ 感覺器官 eye 眼睛 ear 耳朵 nose 鼻子 tongue 舌頭 skin 皮膚 Stimuli detected 探測到的刺激 light 光 sound 聲音 smells of chemical substances 化學物質的氣味 flavours of chemical substances 化學物質的味道 touch, heat, cold, pressure and pain 觸摸 冷熱 壓力和疼痛 Sense 感覺 sight 視覺 hearing 聽覺 smell 嗅覺 taste 味覺 touch 觸覺 2

3 31.2 How we see 31.2 我們如何看見東西 Q3 A3 What are the structures of the human eye? What is/are the function(s) of each structure? 眼睛是由哪幾部分組成的? 每部分各有甚麼功用? The diagram below shows the structures of the human eye and their functions. 下圖顯示人眼的結構, 眼的各部分 各有不同的功用 focusing muscle 對焦肌肉 changes the thickness of the lens 調節晶狀體的厚度 cornea 角膜 helps focus light 有助把光線聚焦 iris 虹膜 controls the size of the pupil 控制瞳孔的大小 pupil 瞳孔 allows light to enter the eye 讓光線從外界進入眼球內 sclera 鞏膜 protects the eyeball 保護眼球 retina 視網膜 contains lightsensitive cells 滿布感光細胞 optic nerve 視神經 transmits messages from light-sensitive cells to the brain 把感光細胞發出的訊息傳送到腦 lens 晶狀體 helps focus light 有助把光線聚焦 jelly-like fluid 玻璃狀液 maintains the shape of the eyeball 保持眼球的形狀 helps focus light 有助把光線聚焦 blind spot 盲點 where the optic nerve leaves the eyeball 視神經離開眼球的地方 contains no light-sensitive cells 不含感光細胞 3

4 Q4 A4 How does the eye control the amount of light entering it? 眼睛如何控制接收的光量? The iris controls the size of the pupil, which in turn controls the amount of light entering the eye. In dim light, the pupil becomes larger. This allows more light to enter the eye so that we can see more clearly. In bright light, the pupil becomes smaller to reduce the amount of light that enters. This prevents strong light from damaging the eye. 眼球內的虹膜控制瞳孔的大小, 從而控制進入眼睛的光量 在光線暗淡的環境下, 瞳孔擴張, 讓更多光線進入眼睛, 使我們可以清楚地看見東西 在光線充足的環境下, 瞳孔縮小, 減少進入眼睛的光量, 避免強光損害我們的眼睛 In dim light, the pupil becomes larger. 在光線暗淡的環境下, 瞳孔擴張 In bright light, the pupil becomes smaller. 在光線充足的環境下, 瞳孔縮小 4

5 Q5 A5 How is an image of an object formed in the eye? 物件的影像如何在眼睛內形成? The diagram below shows how an image of an object is formed in the eye. 1 Light from an object (i.e. the candle) enters the eye. 來自物體 ( 例如 : 蠟燭 ) 的光線進入眼睛 2 The cornea, the lens and the jelly-like fluid help focus the light onto the retina. 角膜 晶狀體和玻璃狀液把光線聚焦 cornea 角膜 下圖顯示物件的影像如何在眼睛內形成 3 retina 視網膜 A sharp and inverted image is formed on the retina. The light-sensitive cells on the retina are stimulated to produce messages. 視網膜上形成一個清晰倒置的影像 視網膜上的感光細胞受刺激後發出訊息 pupil 瞳孔 optic nerve 視神經 lens 晶狀體 jelly-like fluid 玻璃狀液 4 to the brain 往腦部 Messages from the light-sensitive cells are sent through the optic nerve to the brain. 訊息沿視神經傳送到腦 5

6 Q6 A6 How do the focusing muscles and the lens change when we see things at different distances? 當我們觀看不同距離的物 體時, 對焦肌肉和晶狀體 會如何改變? When we look at near objects, the focusing muscles contract and the lens becomes thicker 當我們觀看近處的物體時, 對焦 肌肉收縮, 晶狀體變厚 light from a near object 來自近處物體的光線 near object 近處物體 focusing muscle contracts 對焦肌肉收縮 lens becomes thicker 晶狀體變厚 When we look at distant objects, the focusing muscles relax and the lens becomes thinner. 當我們觀看遠處的物體時, 對焦 肌肉鬆弛, 晶狀體變薄 light from a distant object 來自遠處物體的光線 focusing muscle relaxes 對焦肌肉鬆弛 lens becomes thinner 晶狀體變薄 6

7 Q7 A7 What are the light-sensitive cells on the retina? 視網膜上有哪些感光細胞? Cone cells and rod cells are two kinds of light-sensitive cells on the retina. The following table shows the differences between cone cells and rod cells. 視網膜上有兩種感光細胞, 分別是視錐細胞和視桿細胞視桿細胞 下表顯示視錐細胞和視桿細胞的分別 Cone cells 視錐細胞 three types, sensitive to red, green and blue light 有三種, 分別對紅光 綠光和藍光敏感 responsible for colour vision 負責色覺 work well in bright light 在光線充足的環境下運作最佳 Rod cells 視桿細胞 one type only 只有一種 responsible for black and white vision 負責黑白視覺 important for vision in dim light 在昏暗的環環境下運作最佳 7

8 Revision Helper 溫習錦囊 (Bilingual version) 雙語版本 31.3 視覺上的限制 31.3 Limitations of our eyes Q8 Are there any limitations of our eyes? 我們的視覺是否有限制 A8 Yes, there are some limitations of our eyes. We cannot 我們的視覺是有限制的 我們不能 see objects that are too small, too close or too far away. 清楚看見太小 太近或太遠的物體 Q9 How can we extend our vision? 我們如何克服視覺上的限制 擴闊視野 A9 Scientists have invented a variety of optical instruments to help extend our vision. The following optical instruments can help us see objects that are too small. hand lens 放大鏡 light microscope 光學顯微鏡 The following optical instruments can help us see objects that are too far away. binoculars 雙筒望遠鏡 科學家發明了多種光學儀器 光學儀器 來幫助人 光學儀器 類克服視覺上的限制 擴闊視野 以下的光學儀器 有助我們觀察體積很 小的物體 electron microscope 電子顯微鏡 以下的光學儀器 有助我們觀察距離很 遠的物體 astronomical telescope 天文望遠鏡 Understanding Integrated Science for the 21st Century (3rd Edition) 最新綜合科學 邁進 21 世紀 (第三版) 8

9 Q10 A10 What is blind spot? What happens when light falls on the blind spot? 甚麼是盲點? 當光線落在 盲點上, 會有甚麼發生? The eye has a blind spot on the retina where the optic nerve leaves the eyeball. There are no light-sensitive cells on the blind spot. When light falls on the blind spot, no message is sent to the brain. Therefore we cannot see the images formed on the blind spot. 眼球內的視網膜上有一個盲點, 是視神經離開眼球的地方 盲點是視網膜上一處沒有感光細胞的地方 一旦光線落在盲點上, 由於沒有感光細胞探測光, 也就沒有訊息發出傳送到腦, 因此我們無法看見在盲點上形成的影像 blind spot 盲點 Blind spot on the retina 視網膜上的盲點 9

10 31.4 Eye defects and eye care 31.4 眼睛毛病和眼睛的保護 Q11 A11 Suggest some examples of common eye defects. How can we correct these eye defects? 常見的眼睛毛病有哪幾種? 我們如何矯正這些眼睛毛病? Short sight, long sight, cataract, astigmatism and colour blindness are some common eye defects. 近視 遠視遠視 白內障白內障 散光散光和色盲是最常見的眼睛毛病 1. Short sight 1. 近視 People with short sight cannot see distant objects clearly because the images of the distant objects are formed in front of the retina. Short sight may be caused by the lens being too thick or the eyeball being too long, or both. Short sight can be corrected by wearing glasses with concave lenses. image is formed in front of the retina 影像在視網膜的前方形成 患有近視的人不能夠清楚看見遠處的 物體, 原因是遠處物體的影像會在視網 膜的前方形成 近視是由於晶狀體過厚或眼球過長, 又 或是兩種情況同時出現所引致的 佩戴以凹透鏡凹透鏡製成的眼鏡可矯正近視 concave lens 凹透鏡 sharp image formed on the retina 清晰影像在視網膜上形成 light from a distant object 來自遠處物體的光線 light from a distant object 來自遠處物體的光線 Short sight 近視 Correction of short sight 近視的矯正方法 10

11 A11 2. Long sight 2. 遠視 People with long sight cannot see near objects clearly because the images of the near objects are formed behind the retina. Long sight may be caused by the lens being too thin or the eyeball being too short, or both. Long sight can be corrected by wearing glasses with convex lenses. Image would be formed behind the retina 影像在視網膜的後方形成 患有遠視的人不能夠清楚看見近處的 物體, 原因是近處物體的影像會在視網 膜的後方形成 遠視是由於晶狀體過薄或眼球過短, 又 或是兩種情況同時出現所引致的 佩戴以凸透鏡凸透鏡製成的眼鏡可矯正遠視 convex lens 凸透鏡 sharp image formed on the retina 清晰影像在視網膜上形成 light from a near object 來自近處物體的光線 light from a near object 來自近處物體的光線 Long sight 遠視 Correction of long sight 遠視的矯正方法 3. Cataract 3. 白內障 People with cataracts have cloudy lens. They will 白內障患者的晶狀體會變得混 slowly develop blurred vision, and may even 濁, 所見的影像會變得模糊, 情況 become blind. 嚴重的甚至可以失明 Most cases of cataracts are related to ageing. 白內障在老年人十分常見, 此外糖 Cataracts can also be caused by other factors 尿病 眼睛創傷 長期受陽光照射 such as diabetes, eye injuries, prolonged exposure 及遺傳等因素都會增加患白內障 to sunlight and heredity. 的風險 To cure a cataract, the lens can be replaced with 治療白內障的方法是透過手術, 把 an artificial one through surgery. 混濁的晶狀體換上人工晶狀體 A cataract is an eye defect in which the lens becomes cloudy. 白內障患者的晶狀體變得混濁 11

12 A11 4. Astigmatism 4. 散光 Astigmatism is caused by the cornea or lens (or 散光的成因是角膜或晶狀體的弧 both) being unevenly curved. The light from an 度不均勻, 使光線不能聚焦在視 object cannot be focused onto the retina as a 網膜上形成清晰的影像 sharp image. Astigmatism can be corrected by wearing glasses 佩戴用特別透鏡製成的眼鏡可矯 with specially made lenses. 正散光 5. Colour blindness 5. 色盲 Some people with colour blindness cannot distinguish between certain or all colours. Colour blindness is caused by the absence or defect of one or more types of cone cells on the retina. The most common form of colour blindness is 患有色盲的人不能分辨某些或全部顏色 色盲的成因是視網膜上其中一種或多種視錐細胞的數目不足或不能正常運作 最常見的色盲是紅綠色盲, 患者 red-green colour blindness. People with 不能分辨紅色和綠色 red-green colour blindness find it difficult to distinguish between red and green. Colour blindness is an inherited defect and it is more commonly found in males. It cannot be corrected. 色盲是遺傳的, 男性患者較女性為多 目前還未有方法可以矯正色盲 12

13 Q12 How can we take care of our eyes? 我們應如何保護眼睛? A12 The following are some tips on how we can take care of our eyes. 以下是一些保護眼睛的方法 cm 30 cm Read under sufficient but not strong light. Keep a distance of about 30 cm between your eyes and the book. 在光線充足 ( 但並非強光 ) 的環境下閱讀 ; 書本與眼睛應保持 30 cm 距離 Keep a distance of cm between your eyes and the monitor when using the computer. 使用電腦時, 眼睛與屏幕應保持 50 至 70 cm 距離 After reading a book or using a computer for 30 minutes, take a break and look at distant objects. 閱讀或使用電腦每 30 分鐘, 應讓眼睛休息數分鐘 ; 休息時望向遠處 Always wear safety goggles whenever there is a risk to the eyes during experiments. 進行實驗時, 如有需要應佩戴安全眼鏡 Have regular eye check-ups every year and correct eye defects as soon as possible. 每年定期接受眼睛檢查, 若眼睛出現毛病, 便應及早矯正 Do not rub your eyes to avoid infection. 不要用手揉擦眼睛, 避免受到細菌感染 13

14 Chapter 第 Revision Helper 溫習錦囊 (Bilingual version) 雙語版本 32 章 Hearing 聽覺 32.1 Sound 32.1 聲音 Q13 A13 How is sound produced and transmitted to our ears? 聲音是如何產生和傳送的? Sound is produced by vibrations of objects. When an object vibrates, it causes the surrounding air particles to vibrate. The vibrations of air particles travel through air. When the vibrations reach our ears, we hear the sound. 聲音是由物體的振動振動而產生的 當物體振動時, 會使四周的空氣粒子亦振動起來, 空氣粒子的振動逐漸向四周傳送開去 當空氣粒子的振動傳到我們的耳朵時, 我們便能聽到聲音 vibrations of air particles 空氣粒子的振動 Sound must travel through a medium (e.g. a gas, a liquid or a solid). It cannot travel through a vacuum. 聲音必須透過介質介質來傳送, 介質可以是固體 液體和氣體 然而, 聲音不能夠在真空中傳送 14

15 32.2 How we hear 32.2 我們如何聽到聲音 Q14 A14 What are the main parts of the ear and their functions? 耳朵是由哪些部分組成的? 每部 分各有甚麼功能? The ear is divided into three parts: the outer ear, the middle ear and the inner ear. The diagram below shows the structure of the human ear and their functions. 耳朵可分為三部分, 分別是外耳外耳 中耳和內耳內耳 下圖顯示耳朵各主要部分及其功能 pinna 耳殼 collects sound in the surroundings and directs the sound along the ear canal to the eardrum 收集環境中的聲音, 聲音沿聽道傳送到耳 outer ear middle ear inner ear 外耳 中耳 內耳 ear canal 聽道 eardrum 耳膜 ear bones 聽骨 magnify the vibrations of the eardrum and transmit them to the inner ear 把耳膜傳來的振動放大並傳送到內耳 cochlea 耳蝸 contains receptors that are stimulated by the vibrations to send out messages 從中耳傳來的振動能刺激耳蝸內的感受器發出訊息 auditory nerve 聽神經 transmits messages to the brain 傳送訊息到腦部 15

16 Q15 A15 How do our ears detect sound? 我們的耳朵是如何運作使我們可以 聽到聲音? The diagram below shows the process of how our ears detect sound. 下圖顯示聽覺產生的過程 1 Sound in the surroundings is collected by the pinna. 耳殼收集環境中的聲音 2 The sound travels along the ear canal to the eardrum 聲音沿聽道傳送到耳膜 3 The sound causes the eardrum to vibrate. 聲音使耳膜振動 4 The ear bones magnify the vibrations of the eardrum and transmit them to the inner ear. 聽骨把耳膜傳來的振動放大並傳送到內耳 5 The vibrations stimulate the receptors in the cochlea to send out messages. 振動會刺激耳蝸內的感受器發出訊息 6 The messages are sent along the auditory nerve to the brain. The brain then interprets the messages as sound. 訊息沿聽神經傳送到腦, 腦把訊息詮釋, 產生聽覺 16

17 32.3 Limitations of our ears 32.3 聽覺上的限制 Q16 What is the frequency of sound? 甚麼是聲音的頻率? A16 Sound is produced by vibrations of objects. The number of vibrations per second is called frequency. The unit of frequency is hertz (Hz). The faster the object vibrates, the higher the frequency of the sound it produces. 物體振動會產生聲音 物體每秒振動的次數稱為頻率頻率 頻率的單位是赫茲 (Hz) 物體振動得愈快, 所產生的聲音的頻率便愈高 Q17 Are there any limitations to our ears? 我們的聽覺是否有限制的? A17 Yes, there are limitations to our ears. We can only hear sounds within a certain range of frequencies. We can hear the sound of frequencies from about 20 Hz to 20,000 Hz. This range of frequencies is called the audible frequency range. It varies from person to person. 我們的聽覺是有限制的, 只能聽到特定頻率範圍內的聲音 我們的耳朵能夠聽到介乎 20 Hz 至 20,000 Hz 頻率範圍以內的聲音, 這個頻率範圍稱為聽頻範圍聽頻範圍 每個人的聽頻範圍都有所差異 17

18 Revision Helper 溫習錦囊 (Bilingual version) 雙語版本 32.4 噪音 32.4 Noise pollution What is noise? Suggest some examples of Q18 common sources of noise in Hong Kong. 甚麼是噪音 香港的噪音 有哪些來源 A18 Noise is any sound that is unwanted, disturbing, or so loud that it can cause damage to our ears. The following are some common sources of 噪音是指一些使人煩燥 造成滋 噪音 擾 甚至損害聽覺的聲音 以下是香港的噪音的主要來源 noise in Hong Kong. Cars 車輛 Construction work 建築工程 Airplane 飛機 Machinery 機械運作 Understanding Integrated Science for the 21st Century (3rd Edition) 最新綜合科學 邁進 21 世紀 (第三版) 18

19 Q19 How can we measure the loudness of a sound? 如何量度音量? A19 The loudness of a sound is indicated by its sound level. A decibel meter can be used to measure sound levels. The unit of sound level is decibel (db). 聲音的水平可用音量來表示 我們可以用分貝計分貝計來量度音量 音量的單位是分貝 (db) A decibel meter 分貝計 Q20 A20 How does noise affect us? How can we protect our ears? 噪音對我們有甚麼影響? 我們如何保護聽覺? Long-term exposure to noise may cause mental stress and hearing loss. The following shows some ways of protecting our ears. Avoid staying too long in noisy places, such as karaoke bars and construction sites. Keep the volume low when listening to music, especially when using earphones. Wear ear protectors when working in a noisy environment. Do not pick your ears with hard objects. 長期處於噪音環境會導致精神緊張及聽覺受損 以下是一些保護聽覺的方法 避免長時間逗留在嘈吵的地方, 例如卡拉 OK 場所和建築工地 聽音樂時, 尤其是使用耳筒時切勿把音量調得過高 在噪音環境中工作時, 應戴上聽覺保護器 不要用硬物挖耳朵 19

20 Q21 A21 What measures has the Hong Kong government taken to control noise pollution? 香港政府推出了哪些管制 噪音的措施? The Hong Kong government has taken measures to control noise pollution. The following are some of these measures. 香港政府推出了一連串管制噪音 的措施, 以下是其中一些例子 Reduce the production of noise 減少產生噪音 Cover road surfaces with special materials to reduce traffic noise. 在馬路表面鋪上吸音物料, 以減少馬路與汽車輪胎摩擦時所產生的噪音 Limit the time for noisy construction works to daytime hours on weekdays. 限制建築工程只可在星期一至五的日間時段內進行 Impose penalties on people who disturb neighbours by making noise at night. 任何人不得在晚上製造聲浪滋擾鄰居, 否則會被檢控 Prevent the transmission of noise 阻擋噪音傳送 Protect residential areas from traffic noise by building noise barriers along busy roads and railways. 在鄰近住宅區的高速公路或鐵路旁加建隔音屏障或隔音罩, 以減少噪音對居民的影響 Provide schools with special windows and air conditioning to reduce the noise from nearby road traffic. 資助受噪音滋擾的學校安裝隔音窗戶和冷氣機, 以提供較寧靜的上課環境 20

21 Chapter 第 33 章 Senses of touch, smell and taste 觸覺 嗅覺和味覺 33.1 Sense of touch 33.1 觸覺 Q22 A22 What is the sense organ of touch, heat, cold, pressure and pain? 甚麼感覺器官負責探測觸 摸 冷熱 壓力和疼痛? Skin is the sense organ of touch, heat, cold, pressure and pain. In the skin, there are different kinds of receptors that can detect touch, heat, cold, pressure and pain. When these receptors are stimulated, they send messages to the brain through nerves. The brain then interprets the messages and produces the sensations we experience. 皮膚是負責探測觸摸 冷熱 壓力和疼痛的感覺器官 皮膚內有很多不同種類的感受器, 分別能探測觸摸 冷熱 壓力和疼痛 當這些感受器受到刺激後, 會發出訊息, 訊息沿神經傳送到腦 腦詮釋這些訊息, 產生相應的感覺 pain receptor 痛覺感受器 touch receptor 觸覺感受器 temperature receptor 溫度感受器 pressure receptor 壓力感受器 Different kinds of receptors in the skin 皮膚內不同種類的感受器 21

22 Q23 A23 Are different parts of the skin equally sensitive to touch? 皮膚不同部位對觸覺的敏感度 是否相同? The skin of different parts of the body has a different sensitivity to touch because the touch receptors are not evenly distributed in the skin. Some parts of our body such as the elbows have fewer touch receptors. They are less sensitive to touch. Our fingertips have a lot of touch receptors. They are highly sensitive to touch. 皮膚內的觸覺感受器的分布並不平均, 因此身體不同部位的皮膚對觸覺的敏感度並不相同 身體某些部分, 例如手肘的觸覺感受器較少, 因此對觸覺不大敏感 而指尖則有大量觸覺感受器, 因此對觸覺較為敏感 Q24 Is our skin reliable in detecting heat and cold? 以皮膚探測冷熱可靠嗎? A24 No, our skin is not reliable in detecting hot and cold. 以皮膚來探測冷熱並不可靠 22

23 33.2 Smell and taste 33.2 嗅覺和味覺 Q25 A25 What is the sense organ for smell? How do we detect smell? 甚麼感覺器官負責嗅覺? 我們 如何探測氣味? The nose is the sense organ for smell. There are smell receptors in our nose for detecting smell. When these receptors are stimulated by chemicals in the air we breathe in, they send messages to the brain through nerves. The brain interprets the messages as smell. The figure below show how we detect smell. 鼻子是負責嗅覺的感覺器官 我們的鼻腔內有數百萬個嗅覺感受器嗅覺感受器 當嗅覺感受器受到空氣中的化學物質刺激後, 便會發出訊息, 訊息沿神經傳送到腦, 腦把訊息詮釋, 產生嗅覺 下圖顯示我們如何探測氣味 2 When we breathe in, the chemicals enter our nose and dissolve in the mucus in the nasal cavity. 吸氣時, 這些化學物質被吸進鼻腔內, 並溶於鼻腔內的黏液中 3 The dissolved chemicals stimulate the smell receptors to produce messages. 溶解了的化學物質刺激嗅覺感受器產生訊息 4 The messages are sent through the nerve to the brain where they are interpreted as smell. 訊息沿神經傳送到腦, 腦把訊息詮釋為氣味 1 Chemicals from the food spread in the air. 食物的化學物質擴散到空氣中 mucus 黏液 nerve 神經 smell receptors 嗅覺感受器 23

24 Q26 A26 What is the sense organ for taste? How do we detect taste? 甚麼感覺器官負責味覺? 我們如何嚐到味道? The tongue is the sense organ for taste. On the tongue, there are taste buds, each of which contains a group of taste receptors. When these receptors are stimulated by flavouring chemicals in food or drink, they send out messages to the brain through nerves. The brain interprets the messages as taste. There are four types of taste receptors in the taste buds. Each type detects one of the four primary tastes: sweet, sour, salty and bitter. The figure below shows the process of how the sense of taste is produced. 舌頭是負責味覺的感覺器官 舌頭上有多個味蕾, 每個味蕾內有很多味覺感受器 當味覺感受器受到食物或飲品中的化學物質刺激時, 會發出訊息, 訊息沿神經傳送到腦, 腦把訊息詮釋, 產生味覺 味蕾上有四種味覺感受器, 分別探測甜 鹹 苦和酸四種基本味道 下圖顯示味覺產生的過程 taste bud 味蕾 1 Chemicals in food dissolve in the saliva. 食物中的化學物質溶於唾液中 1 2 taste receptor 味覺感受器 2 The dissolved chemicals stimulate taste receptors to produce messages. 溶解了的化學物質刺激味覺感受器發出訊息 chemical in food 食物中的化學物質 3 to the brain 訊息傳送到腦 3 The messages are sent through nerves to the brain where they are interpreted as taste. 訊息沿神經傳送到腦, 腦把訊息詮釋為味道 24

25 Q27 A27 What is the relationship between our senses of smell and taste? 嗅覺和味覺有甚麼關係? Our sense of smell affects our sense of taste. They work together to detect the flavour of food. 我們同時用嗅覺和味覺來探測食物的 味道, 鼻子所探測到的氣味會影響舌 頭所探測到的食物味道 25

26 Chapter 第 34 章 The brain and our senses 腦和我們的感覺 34.1 Understanding the brain 34.1 認識腦部 Q28 A28 What is the role of the brain in sensing the environment? 腦在察覺環境中的角色是怎樣的? The brain receives messages from the sense organs. After interpreting the messages, it sends messages to the muscles to make responses. The figure below shows the process of detecting stimuli and making responses. 腦接收從感覺器官傳來的訊息, 把訊息加以分析, 產生感覺, 然後作出決定, 發出訊息到肌肉, 使肌肉作出反應反應 下圖顯示探測刺激和作出反應的過程 stimulus 刺激 sense organ 感覺器官 brain 腦 The alarm clock rings. 鬧鐘響起 Ears detect the sound of the alarm and send messages to the brain. 耳朵探測到鬧鐘的聲響, 並發出訊息傳送到腦 The brain interprets the messages, produces the sensation and decides what to do. 腦分析來自感覺器官的訊息, 產生感覺, 並作出決定 muscles 肌肉 4 5 response 反應 The brain sends messages to the muscles. 腦發出訊息到肌肉 The muscles make a response: getting up to turn off the alarm. 肌肉作出反應 : 起床並關掉鬧鐘 26

27 Q29 What are the main parts of the brain and their functions? 腦主要由哪幾部分組成? 每部分各有甚麼功能? A29 The brain is made up of three main parts: the cerebrum, the cerebellum and the medulla. The figure below shows the main parts of the brain and their functions: 腦由大腦大腦 小腦小腦和延髓三個主要部分組成 下圖顯示腦的主要部分及每部分的功能 medulla 延髓 controls heartbeat, breathing and blood pressure, etc. 控制心跳 呼吸和保持血壓等 cerebrum 大腦 interprets the messages from sense organs 分析來自感覺器官的訊息 sends messages to the muscles to make response 發出訊息到肌肉以作出反應 responsible for intelligence, memory and thinking 負責智力 記憶和思考 cerebellum 小腦 coordinates muscles to produce body movement 協調肌肉 控制身體運動 maintains the balance of the body 保持身體平衡 Q30 What is reaction time? Can it be improved by training? 甚麼是反應時間? 反應時間 可否透過訓練而縮短? A30 Reaction time is the time between detecting a stimulus and making a response. It varies from person to person. Reaction time can be improved by training. 反應時間是指身體由探測到刺激到作出反應所需的時間 反應時間的長短因人而異 反應時間可以透過訓練而縮短 27

28 Q31 What are illusions? 甚麼是錯覺? A31 When the brain interprets messages incorrectly, illusions may result. 腦有時會錯誤分析訊息, 產生錯覺 34.2 Effects of alcohol, drugs and solvents on our senses 34.2 酒精 藥物藥物 毒品和溶劑對我們感覺的影響 Q32 What are the effects of alcohol on us? 酒精對人體有甚麼影響? A32 Alcohol slows down our responses to stimuli (i.e. increasing the reaction time) and affects our judgement of speed and distance. It can affect our body coordination, sight and hearing, speech, etc. Drinking too much alcohol in the long term can damage the brain and the liver seriously. 酒精會使人反應遲緩 ( 即延長反應時間 ) 和影響我們判斷速度和距離的能力 酒精亦會影響身體協調能力 視覺和聽覺 說話能力等 長期過量地飲酒會嚴重傷害腦和肝臟 Q33 What is a breathalyser? 甚麼是酒精測試機? A33 The breathalyser is a device for measuring the amount of alcohol in one s breath. It contains acidified dichromate solution. If one s breath contains alcohol, the acidified dichromate solution reacts with the alcohol and turns from orange to green. The higher the content of alcohol in one s breath, the greener the solution. 用來量度酒精含量的儀器稱為酒精測酒精測試機 酒精測試機內含有已酸化的重鉻酸鹽溶液, 當測試者呼出的空氣中含有酒精時, 已酸化的重鉻酸鹽溶液會與酒精反應, 並由橙色變為綠色 測試者呼出的空氣中酒精含量愈高, 溶液所呈現的綠色便會愈深 Understanding Integrated Science for A driver the 21st being Century tested (3rd Edition) with a 最新綜合科學 breathalyser 邁進 21 世紀 ( 第三版 ) Aristo Educational Press Ltd 2012 警員利用酒精測試機為駕駛者進行呼氣測試 雅集出版社有限公司

29 Q34 What are the effects of drug abuse? 吸食毒品會對人體構成甚麼影響? A34 Drug abuse brings harmful effects on the nervous system, particularly the brain. It can slow down a person s reaction, affect his/her judgement and cause illusions. It can also affect the mood and behaviour of a person. When a person abuses drugs, he/she may feel angry, anxious or depressed. 吸食毒品會損害我們的神經系統, 包括腦部 吸食毒品會使人反應遲緩和判斷能力下降, 產生錯覺 吸食毒品亦會影響人的情緒和行為, 吸毒者會感到憤怒 焦慮或抑鬱 Q35 What are the effects of solvents on us? 嗅溶劑會對人體造成甚麼影響? A35 Sniffing organic solvents (e.g. thinner) damages the nervous system and can lead to addiction. Exposure to these solvents will irritate the eyes and the respiratory system. When sniffed, the chemicals get into the blood through the lungs quickly and may lead to the following: loss of judgement and muscle control damage to the lungs and the brain death 嗅有機溶劑 ( 例如 : 天拿水 ) 會對神經系統造成影響, 令人上癮 有機溶劑揮發出來的氣體會刺激眼睛和呼吸道系統 當人吸入這些氣體時, 氣體會迅速地經肺部進入血液中, 並可能會引致以下後果 : 失去判決能力和控制肌肉的能力 損害肺和腦 死亡 29

30 Part 2 第 Revision Helper 溫習錦囊 (Bilingual version) 雙語版本 部分 Revision exercise 單元練習 A. True or false questions 是非題 Write T for a true statement or F for a false statement in each box provided. 細閱以下句子, 正確的在方格內填上 T, 不正確的則填上 F 1. The receptors in the ears can detect sound only. 2. The cornea is colourless and helps focus light. 3. There are some light-sensitive cells on the blind spot. 4. Sound cannot travel through a vacuum. 5. Frequency is the number of vibrations of an object per minute. 6. The four primary tastes are sweet, sour, salty and bitter. 7. Reaction time is the same for everyone. 8. Alcohol and drug abuse causes addiction. B. Multiple-choice questions 多項選擇題 Choose the correct answer for each of the following questions. 選出正確的答案, 然後在空格內填上代表該答案的英文字母 1. Which of the following are sense organs? (I) Eye (II) Hair (III) Nose A. (I) and (II) only B. (I) and (III) only C. (II) and (III) only D. (I), (II) and (III) 2. Which of the following structures of our eyes has colour? A. Cornea B. Iris C. Lens D. Jelly-like fluid 3. Which of the following eye defects CANNOT be corrected? A. Short sight B. Cataract C. Astigmatism D. Colour blindness 30

31 4. Which of the following media can sound travel through? (I) Air (II) Wood (III) Water A. (I) and (II) only B. (I) and (III) only C. (II) and (III) only D. (I), (II) and (III) 5. Which of the following stimuli can be detected by skin? (I) Touch (II) Pressure (III) Pain A. (I) and (II) only B. (I) and (III) only C. (II) and (III) only D. (I), (II) and (III) 6. Which of the following statements concerning our tongue are correct? (I) It is the sense organ for taste. (II) There are five types of taste receptors in the taste buds on the tongue. (III) The smell detected by our nose will affect the taste detected by our tongue. A. (I) and (II) only B. (I) and (III) only C. (II) and (III) only D. (I), (II) and (III) 7. Which of the following is NOT the function of cerebrum? A. It controls heartbeat, breathing and blood pressure. B. It is responsible for intelligence, memory and thinking. C. It sends messages to the muscles to make responses. D. It interprets the messages from sense organs. 31

32 8. Which of the following statements concerning a breathalyser are correct? (I) It contains acidified dichromate solution that can react with alcohol and turns from green to orange. (II) It is a device for measuring the amount of alcohol in one s breath. (III) The degree of the colour of the solution can indicate the amount of alcohol in one s body. A. (I) and (II) only B. (I) and (III) only C. (II) and (III) only D. (I), (II) and (III) C. Short questions 短問題 1. The diagram below shows the structures of the human eye. A B C (a) Identify the labelled parts of the human eye and state their corresponding functions. (b) When a person looks at distant objects, how will A and C change? (c) When a person enters a dark room, how will B change? (d) (i) (ii) If a person has long sight, what problem does he have in seeing? How can long sight be corrected? 32

33 2. The diagram below shows the structures of the human ear. A B C (a) Identify the labelled parts of the human ear. (b) What happens to B when the sound reaches it? (c) Suggest two ways for protecting our ears. 33

34 art Answers 答案 A. True or false questions 是非題 1. T 2. T 3. F 4. T 5. F 6. T 7. F 8. T B. Multiple-choice questions 多項選擇題 1. B 2. B 3. D 4. D 5. D 6. B 7. A 8. C C. Short questions 短問題 1. (a) A is focusing muscle. It changes the thickness of the lens. B is pupil. It allows light to enter the eye. C is lens. It helps focus light. (b) A (the focusing muscle) relaxes and C (the lens) becomes thinner. (c) B (the pupil) becomes larger. (d) (i) He cannot see near objects clearly. (ii) Long sight can be corrected by wearing glasses with convex lenses. 2. (a) A is pinna. B is eardrum. C is cochlea. (b) B (the eardrum) vibrates. (c) Avoid staying too long in noisy places, such as karaoke bars and construction sites. Do not pick your ears with hard objects. (or any other reasonable answers) 34