中考复习知识点.doc

中考复习知识点The important concepts, rules and theories of the midtermRemember the name and heat of the six changes in the state of the state.Remember the six laws of physics: (1) Newton，s first law (the law of inertia) (2) the reflection law of light (3) light(4) the law of transformation and conservation of energy (5) ohm，s law (6) joule，s law. Remember the two principles: (1) the Archimedes principle (2) the principle of leverageQuality is the property of an object: changes in shape, geography, state, and temperature. And gravity varies with position.Density is the property of matter, independent of m, v, but it changes with state and temperature. Inertia is the property of the object, it only has to do with the mass of the object,It has nothing to do with the force of the object, motion or movement. Specific heat capacity is the property of matter: it is only related to matter, state, quality and temperature.Resistance is the property of a conductor: it has to do with the type, length, thickness, and temperature of the material, regardless of current or voltage.4, scientific inquiry has seven elements: ask questions, conjecture and hypothesis, planning and design experiment, experiment evidence collection, analysis, evaluation, exchanges and cooperation.The physical method is reflected in the process of studying thelaws of physics, which is mainly analogous, equivalent substitution, false contrivation, controlling variable law,The ideal model method, transformation method and so on.Control variables: when researching a problem, only one factor(that is, a variable) is changed, while other factors are notChange, such as exploring the relationship between I and U, R, and exploring the factors associated with evaporation.Equivalent substitution (for example, the net force, the total resistance), the model method (for example, the atomic nucleusStructural models, magnetic lines, light), analogies (such as current and water, voltage and water pressure). Conversion method (the principle of an ammeter, using a thermometer to measure temperature, a small field to test the magnetic field)6, electricity experiment points should be paid attention to: (1) in the process of connecting circuit, switch in the off state. (2) before the closing switch, slide rheostat in the maximum resistance state, a connection to a.Measured resistance should be parallel in both ends (3) voltmeter, ammeter in series in the circuit. (4) ammeter and voltmeter musttake the current in the circuit from terminal to enter, the outflow from the negative terminal.7, is the basic instrument and tool use: scale, watches and clocks, liquid thermometer, balance (level adjustment, cross rail balance adjustment, swim yards), measuring cylinder, measuring cup, springdynamometer, density meter,Electric current meter, voltmeter, slide rheostat, measuring pen, electrical energy meter.Media: all solid, liquid and gas except for vacuum.Light: vacuum, air, water, glass, etcCommon (1) crystals (with certain melting points) : sea wave, ice, quartz, crystal, salt, alum, naphthalene, various metals(2) non-crystal: rosin, glass, beeswax, asphaltCoimnon (1) conductors: aqueous solution of metal, graphite, human, earth, acid, alkali, salt(2) insulation: rubber, glass, ceramics, plastics, oilCoimnon conductive body: metal, undesirable heat conduction body: air, water, wood, cotton etc.The new materials are nanomaterials, superconducting materials, memory alloys, and invisible materials.The relationship between motion and force: the original stationary object: if a is balanced: stay still. B is the non-equilibrium force: moving in the direction of the net force(2). The original movement of objects: if a balance: keep the uniform motion in a straight line. B. the non-equilibrium force: ifthe direction of force and motion in the same direction, theobjects to do accelerated motion.If the direction of the force is opposite to the direction of motion, the object does a slow motion. If the direction of the force is not in line with the direction of motion, the motion of the object changes.If the object is not stressed or the equilibrium force will remain in equilibrium, the object is stationary or in a uniform velocity, the force of the object is balanced, and the net force is zero. The object is affected by a non-equilibrium force.12, family circuit connection method: (1) among electrical appliances and socket are in parallel, (2) switch wire at one end, side light bulbs, (3) bulb screw set to pick up on the zero line(4)The fuse was attached to the wire. The connection of the three-hole socket is ground to the left zero right fire.Temperature, heat, and internal energy: temperature rise maybe absorbed by heat (or work); When heat is absorbed, the temperature tends to rise (when the crystal melts and the liquid boils at the same temperature),Can increase: It increases in energy, maybe it absorbs heat, it increases temperature.The condition of the crystal melting: to reach the melting pointand continue to absorb the heat and solidify into a crystal condition: to reach the freezing point and continue to heat. Conditions for boiling liquid: reach boiling point and continue to absorb heat.The condition of work: force and move a distance in the directionof force.Conditions of induction current: closed circuit and partial conductor cutting magnetic inductance.15. The common light straight line dissemination: small hole imaging, the formation of the shadow, hand shadow play, the laser collimation, a solar eclipse, lunar eclipse, queuing, check whether the object is to close one eye. The aim of the shooting, 〃to sitin the sky and see little”,Determine your vision (a leaf spot) to see if you can see an object or imageReflection of common light: the plane mirror image, the reflection in the water, the sight of the non-luminous object, the periscope, the bicycle taillight (reflector).Coimnon refraction: look at fish in the water and fish and fish. The chopsticks in the water will bend up. People who see throughthe campfire will tremble. See the sunrise. A mirage, amagnifying glass, the stars blink (flashing).Image: a real image: a hole image (sun spot); Camera (movie); Slide projector (convex lens u > f)The image of a mirror image: a mirror, a periscope, a reflection in the water, a smooth surface. Lens image: a magnifying glass (an old mirror) looking at an object, a concave lens forming a shrinking image (myopic mirror); (3) refraction phenomenonLook at objects in water: look at objects and amber through water and glassThe image of a magnified image: the image of the convex lens u < 2fThe image of a convex lens, the image of a concave lens formed by a convex lens u > 2fThe image of a flat mirror, periscope, convex lens u 二2f(6)the image of a plane mirror image: waiting for a large, equal distance image.(7)the pattern of convex lens imaging: when u > 2f, it is inverted, reduced, like an fThe magnitude of the forceGravity (G) : straight down G 二mg 二rho vgPressure (F) : perpendicular to the pressure surface F = G (the object is placed on a horizontal surface and is not subject to other forces in the vertical direction)Normal force (N) : vertical exposure to the external N = F pressure (supporting force and pressure is a pair of forces andcounterforces)Friction (f) : in the opposite direction of motion f = f.Pull (force) (F) : in the same direction as the force (as with the rope and the hand)Resultant (F) = Fl + F2 =(the same direction) = Fl - F2 (the opposite direction)Buoyancy (F float) : upwards F = G row = rho liquid gvThe common spreading phenomenon (the essence is that molecules are doing no rules) : 1), salted eggs with salt water, and salted eggs. The fragrance of osmanthus flowers in August. 3), the ink (sugar, salt) in the water for a while,The glass of water is black (sweet and salty). 4) the long coal wall is dyed black. 5) you can smell fruit in the fruit store and smell the food, (the smell is spreading).6), vaporization and sublimation are also diffuse phenomena: alcohol is applied to the skin and can smell alcohol. Camphor balls have been lost for some time.The method of increasing friction: the roughness of the contact surface. Increase the pressure; Slide instead of scrolling. Like (1) the edge of the plastic cap is usually a few bumps and vertical stripes (2) on the frozen snow road,The rear wheels of the car often have to be wrapped in a chain ofsafety,(3)the bicycle brake with decorative pattern on the set of plastic pipe (4) brake are printed on the tire pattern (5) hand oil bottle with great force patterns (7) (6) sole bundle weight with hemp rope (8)Silk jaw engraved with the pattern (9) picked up a heavy force (10) a car stuck in the mud, in front of the tyre cushion some of the stones and sand reduces friction method: (1) reduce pressure (2) make contact surface more smooth. To separate the contact from one another,For example, lubricating oil, air cushion, magnetic suspension. You can use scrolling instead of sliding. For example: (1) when moving heavy objects, people usually put the weight on the rollers, (2) to lubricate the machine，s lubricating oil (3) on the bicycle shaft(4)add some graphite or oil to the lock, and the lock is very good Explain common inertia: A, shake off the water in your hand.B, the car can still go a long way before it is shut down. C, people walking on a moving train, when the train suddenly breaks on the brakes, and the car moves forward,Have to wear a seat belt in the front row, in case of emergency braking E, aircraft bomb to hit the target, must be in before the goal above, throwing in advance F, on the coal into coal stove H G, motorcycle jump within obstacles,Flapping clothes, the dust that attaches to the clothes, the hair that shakes off the hair of the barber's cloth, the athlete runs to the finish line, can，t stop immediately21. Increase the pressure method: (1) a knife and your job (blade grinding thin) (2) the doctor for injection needle iron nails done very sharp (3) the tip the more likely it is to knock into the wood (4) pins are doing cap garden nozzle (5 w very sharp mouthIce skates for ice skatesDecrease the pressure method: (1) the camel feet is several times than the horse (2) add drag (tank) will be tracked (3) the sofa comfortable than sit stool (4) pins are doing cap garden nozzle (5) of bag often do very wideThe large truck that carries the steel is more than the wheel of the ordinary car, and the foundation of the bed of the sleeper is wider than the wall on the ground.。