人体中的物理学知识（Physics knowledge in human body）

1、人体中的物理学知识（Physics knowledge in human body）Physics knowledge in human bodyFrom life to physics, from physics to life is one of the main teaching ideas of the new physics curriculum in middle school. In teaching to cultivate students abilities to observe, analyze and apply the knowledge to students wi

2、th ability of familiar things and life experience, make students feel that physics is around, physics is so mysterious, is not so difficult to learn, learn it very interested. Human beings are the most advanced primates. The human body is one of the most complex life forms in life evolution. What ar

3、e the junior physics knowledge involved in the human body? The use of human body this course resources of students to review, can exercise students observation ability, divergent thinking ability and the ability to use physics knowledge to analyze problems. Review in junior physics, I specially arra

4、nged a lesson in the body of physics knowledge, students enthusiasm is very high, to speak of physical contact with life, to further improve the students interest to study physics in daily life.In class, we introduce the subject first. Students, human beings are the most advanced primates. The human

5、 body is one of the most complex life forms in life evolution. What physical knowledge do we learn? Ask students to use their brains, to discuss in groups, to ask as many questions as possible, and to answer questions that can not be solved, can be left to the final discussion of the class, the time

6、 is about 10 minutes. Then, each group communicated with the whole class and asked or answered the most questions.When communicating, students are very active and eager to express their views. The teacher wrote the questions raised by the students on the blackboard, answered the imperfect ones, supp

7、lemented by other groups, and avoided the repetition of the same problems. Finally, the students generally put forward and clear the following aspects of the problem, for your exchange and reference:First, mechanics knowledge1. knowledge of pressure(1) peoples teeth use the knowledge of pressure. Th

8、e incisor and canine teeth is sharp, pointed teeth and double grinding tooth crown with sharp protuberances, these are less accepting area, which increases the pressure to facilitate the bite of food or take food from people.(2) the size of a persons foot, the general law is that the foot of a tall

9、person is also larger, so that people with different weight to walk on the ground pressure is basically the same.(3) people inhale, chest to chest lung volume increases, the volume of a gas quality increases, the pressure is reduced, less than atmospheric pressure outside, the air pressure into the

10、respiratory tract into the body of the alveoli; when you exhale, the chest muscle contraction oppression make it reduce the volume of lung, lung gas the quality of the reduced volume pressure increases, which is greater than the atmospheric pressure, exhaled carbon dioxide.(4) the flow of human bloo

11、d is the pressure produced by the contraction of the heart.2. knowledge of friction(1) in the human oral cavity, the surface of the tongue is rough, and there are also lines on the upper jaw, these structures increase the friction with food, easy to stir food or put things into the esophagus.(2) the

12、re are special palm prints on the palms and soles of the feet. When the grip strength is fixed, the fingerprints and palm prints on the palm can increase the friction with the contact material, which makes it easy for people to grasp what they want to take. The pattern on the soles of the feet can i

13、ncrease friction, make people walk the road, feet and socks, shoes slipping, more strength.(3) when people walk, the friction between the foot and the ground, foot and back, there is relative to the backward movement trend, with sole produces friction to prevent the foot with respect to the backward

14、 motion, this force is the force forward, make people forward.3. simple machinesThe human forearm is a hard lever. The elbow is the fulcrum of it. When the object is lifted, the gravity of the object is the resistance acting on it, and the force exerted on the biceps is its power.FourKnowledge of en

15、ergy(1) people eat food after digestion, the large molecules cannot be absorbed directly into the small molecule can be absorbed into the cells of the digestive tract, chemical changes in the cells, the biomass energy is converted into chemical energy being used.(2) the physiological curvature (cerv

16、ical curvature, thoracic curve, lumbar curvature and sacral flexure), and the arch, the femur and the tibia bending, the spring like bicycle seat under the same, can walk up and down movement or kinetic energy in the process of jumping into elastic potential energy, can effectively reduce the influe

17、nce of vibration line go in the process of the brain.Two. Knowledge of heat(1) in a long time of intense activity, the body will produce a lot of heat, the heat is not distributed in a timely manner, will lead to the normal physiological activities of human destruction, human sweat will promptly sec

18、rete sweat, absorb a lot of heat of the body sweat evaporation, the body temperature is maintained at a constant temperature of 37 DEG C steady state. When the weather is high, the heat of the human body is difficult to emit, the body will also be a large number of sweating way to heat.(2) hair not

19、only has cosmetic effect, but also regulates the body temperature and protects the brain. In winter, the cold wind, vasoconstriction, hair can keep the head in a certain amount of heat; summer, the scorching sun, the hair can block the direct sunlight damage to the scalp and hair at the same time, t

20、he expansion of blood vessels, can dissipate heat. Therefore, hair has the dual functions of both heat preservation and heat dissipation.Three. Optical knowledge(1) human eyes are the most sensitive camera. The pupil of the eye is like the aperture of the camera, the intensity of the light varies, t

21、he size of it changes; the lens is like a convex lens, and its focal length can change; the retina is like a film. In normal eyes, when people look at distant objects, reduce the curvature of the lens focal length, larger; see close objects, and the curvature of the lens focal length becomes larger,

22、 smaller, can be kept as clearly into the retina.(2) the body has a certain temperature, will emit a certain wavelength of infrared. But there is inflammation somewhere in the human body. When the temperature increases locally, the intensity of the infrared radiation will change. Therefore, medical

23、infrared photography can be used to assist the diagnosis.(3) peoples eyes determine the specific position of objects according to the straight line propagation of light. When people use one eye to see objects, not only two eyes to see clearly, but also against the light to see the past, can not dete

24、rmine the object from the distance, can not determine the exact location of the object; and two eyes watching, against the light to see the past, the light cross position, is the object the location of the.Four. Electrical knowledgeThe human body has biological current, and it can be used to detect

25、the biological current of the human body by medical equipment, so that the work condition of human tissue can be known. Such as: Medical ECG, EEG, is based on this phenomenon made. Lie detector is also based on the human body to judge the current situation. When people lie, the biological current of

26、 human body will change abnormally. According to the bioelectric current, whether the lie can be judged or not can be judged.Five. Knowledge of acoustics(1) the vocal cords of human beings vibrate and make sounds, so that people can communicate with each other by language. Different people have diff

27、erent vocal cords, and they produce different sounds when they make sounds. We can tell who is speaking by the sound.(2) the human ear is the auditory organ, and the sound is transmitted into the human ear through the vibration of the air. The vibrating air causes the eardrum to vibrate, the eardrum

28、 sends the vibration to the auditory ossicles, passes through the auditory nerve to the brain, forms the hearing.(3) the transmission of sound requires medium. Human bones can transmit sound, and if only conductive hearing loss, you can use bone conduction method to hear the sound.(4) the binaural e

29、ffect helps people to judge the location of sound sources.The distance from the source to the two ear is generally different, and the time and intensity of the sound transmitted to the two ear are different. According to these differences, one can judge the location of the sound source.Physical phen

30、omena around us1, hanging on the wall of the clock on the wall, when the battery power depletion and stopped, the second hand often stop on the dial 9 position. This is due to the hindrance by the second moment in the 9 position of the maximum.2, sometimes tap water pipe in the vicinity of the tap w

31、ater, occasionally bursts of noise. This is due to the resonance of the water pipe caused by the water coming out of the tap.3, to take pictures of the TV picture, should close the camera flash and indoor lighting, so that the photos are more clear picture. The reflected light on the TV screen inter

32、feres with the transmitted light of the TV screen.4. Frozen pork thawed faster in water than at the same temperature. Burn the nails in the water than the cooling at the same temperature air. The cup with hot boiled water is immersed in water faster than the air at the same temperature. These phenom

33、ena indicate that the heat transfer of water is better than that of air.5, the pot filled with cold water, the outer surface of the bottom of the water on the flames attached long time to be burned, and until Shaogan not boiling, this is because the water droplets, pot and a pot of water to keep the

34、 three heat conduction, temperature is roughly the same, as long as the pot of water without boiling, water will not boil. Water droplets in the flame by evaporation and gradually burned dry.6, the shape of the mirror, people far away from the mirror, more aliasing. Because the mirror is formed by t

35、he mirror after the silver surface reflection formed, silver plating uneven surface or glass uneven thickness, will produce aliasing. The farther away from the mirror, the larger the distance of the reflected light from the silver surface to the normal position, the more distorted the mirror is.The

36、side jet nozzle 7, natural gas furnace has several holes communicated with the outside, but not natural gas from the side hole ejected from the nozzle only. This is due to air velocity at the nozzle gas, according to the principle of fluid mechanics, high velocity, low pressure, high pressure air pr

37、essure on the side hole of the outer surface of the small the strong, so the natural gas not to spray nozzle side hole.8, the balloon, pinch the mouthpiece by hand, and then suddenly let go, the air is sprayed out from inside the balloon, the balloon for recoil movement. You can see the twists and t

38、urns of the course of the balloon movement. There are two reasons: one is the big blow of the balloon around the uneven thickness, uneven tension, the balloon deflated when everywhere uneven contraction and swing, thereby changing the direction of movement; two is the balloon in the process of contraction of shape changing, so the air velocity in the process of movement at the surface of the balloon are constantly changing and according to the principl