1. Generation and spread of sound
The generator is vibrating-experiment; Sound travels through media-media: all solids, liquids and gases; Vacuum can't transmit sound.
Sound speed-the sound speed in the air (about 340m/s); Velocity in general solid >: velocity in liquid >: velocity in gas; The speed of sound increases with the increase of temperature.
Echo-Time and distance required for echo; App application
Calculation-Combined with Travel Problem
2. Tone, loudness and timbre
Objective quantities-frequency (pay attention to the range of human hearing and vocalization) and amplitude.
Subjective quantities-pitch and loudness (meaning high or low); Factors affecting loudness: amplitude, distance and dispersion.
Timbre-function; The timbre is determined by the vocal body itself.
3. Harm and control of noise
Noise-noise in physics and life (physics-irregular vibration, life-sounds that affect work, study and rest); Noise level: dB (0dB-only causing hearing); Methods to reduce noise (at the sound source, during propagation, at the human ear); Four major pollutions (air pollution, water pollution, solid waste pollution and noise pollution)
1. Light source-torches, candles, electric lights, stars (the moon and planets are not light sources).
2. Linear propagation of light
Linear propagation (uniformity) of light conditions; Can spread in vacuum; Phenomena (laser collimation, shadow, pinhole imaging P78 and light spots under trees, solar and lunar eclipses); The speed of light in vacuum (3× 10[sup]8[/sup]m/s), and the light year is the unit of length.
3. Light reflection
Law of reflection-three lines * * * surface; Separate the two sides; Equal angle; The optical path is reversible (note that the narrative order should conform to the causal relationship)
Specular reflection and diffuse reflection-every ray conforms to the law of reflection (phenomenon explanation: polished metal surface, calm water surface, ice surface and glass surface can all be regarded as mirrors; Others are regarded as rough surfaces, P79 Figure 5-40; Should be answered according to the phenomenon)
4. Flat mirror
Plane mirror imaging-regularity (equiaxial, equiangular, upright, virtual image); The range of visible (invisible) images; periscope
5. Drawing-Drawing according to relevant laws.
1. Refraction of light
Refraction-definition (... direction usually changes); Law of refraction (three lines * * * plane, two sides, different angles; The optical path is reversible; Pay attention to the narrative order to conform to the causal relationship); Phenomenon explanation (shallow fish in water, bent chopsticks in water, mirage, etc.). )
2. The comprehensive problem of light propagation
Pay attention to distinguish between refracted light and reflected light; Pay attention to distinguish between different shadows and images.
camera lens
Terminology of lenses-principal optical axis, optical center, focal length and focal point (method of measuring focal length)
The effect of convex lens and concave lens on light-the difference between "convergent light" and "convergent light": "convergent light" refers to the light that can converge to a point, and "convergent light" refers to the light that is closer to the main optical axis after passing through the convex lens than before)
Principle of multi-prism combined lens; The light is refracted on both sides of the lens.
Changed convex lenses-glass balls, round bottles of water, water drops on glass plates, etc.
Black box problem
4. Convex lens imaging
Three kinds of special light (passing through the center of light-the direction is unchanged; Parallel to the main optical axis-optical center; Light passing through the optical center-parallel to the main optical axis); The relationship between image distance/image size/virtual reality/upside down and object distance; The speed of image movement (based on: optical path diagram); practical application
1. thermometer
Thermometer-material, principle and measuring range of common thermometer (thermometer: 35 ~ 42℃; Thermometer: -20~50℃)
How to use-the structure and use of thermometer (necking part; Function and principle of throwing thermometer; The consequences of not throwing-only affecting low temperature measurement), the use of thermometer (pay attention to the selection of range); Calibrate the thermometer; Reading (generally you can't leave the object when reading)
Temperature scale-centigrade scale, thermodynamic temperature scale and conversion; Absolute zero; Ordinary temperature
2. State transformation
Melting and solidification-experimental device (water bath heating); Common crystals and amorphous; Melting point and freezing point; picture
Vaporization-evaporation; Factors affecting evaporation rate; Boiling experimental device; The connection and difference between evaporation and boiling (both evaporation; Intensity, occurrence conditions, etc. ); Use of alcohol lamp (refer to chemistry)
Liquefaction-two ways (cooling will definitely liquefy the gas; Compression can liquefy gas)
Sublimation and Sublimation-Examples
3. Heat transfer in the change of state of matter
Heat absorption-solid → liquid → gas (even if the temperature is constant, there is heat transfer); Exothermic gas → liquid → solid
4. Others
Phenomenon explanation-for example: P3 Figure 0-3, refrigerator principles such as boiling water in paper pot, "white gas" and water droplets (liquefaction) on glass, frost, dew, clothes drying (evaporation sublimation) and camphor; Heat calculation in the change of material state; Pay attention to the writing of nouns (steam, gas; Dissolve, melt, melt; China, China; Coagulation) and letters (t and t; C and k)
Chapter IV Circuits
1. Two kinds of triboelectrification charges
Static electricity-the judgment of charge type; Electroscope structure (P45 diagram); Electricity (unit: coulomb c)
Material microstructure-atomic structure (can be compared with the concept of atom in chemistry); The cause of triboelectrification (electron transfer outside the nucleus)
2. The corresponding circuit concept
Current (and direction: the direction of positive charge movement); Power supply; Conductors and insulators; Series and parallel connection; Free charge and direction of motion in the circuit; Circuit diagram; Paths, open circuits and short circuits; Ordinary circuit (corridor circuit; Refrigerator Circuit: Volume I P60 Figure 4- 18)
Judgment of equivalent circuit-first remove the ammeter/voltmeter (ammeter: short circuit; Voltmeter: open circuit) before making a judgment.
1. Definition, unit (unit symbol), meaning and conversion of each physical quantity (I, U, R, P)
Usage of ammeter and voltmeter (range and range selection, series and parallel connection, positive and negative poles, whether they can be directly connected to both ends of power supply) and their structures.
2. Measurement of resistance (basic methods and changes); Factors affecting resistance; Structure and use of sliding rheostat (P94 Figure 7-7); Use and reading of variable resistance box (P95 Figure 7-9, 7-10; Potentiometer); Deformation of sliding rheostat (e.g. p 10 1 Figure 7- 19)
3. Ohm's law and deformation (pay attention to the physical meaning)
4. Series-parallel current, voltage and resistance formulas (note the conditions. For example, power is directly proportional to resistance in series connection and inversely proportional to resistance in parallel connection; Joule's law only applies to pure resistance circuits, and it applies to all circuits when calculating heat.
Common conclusion (each proportional formula; When the resistance of sliding rheostat changes, the changes of each physical quantity in the circuit-pay attention to the derivation order)
5. Electricity-W = UIT = UQ; Electric energy meter and measuring power with electric energy meter (P130);
Electrical nameplate; Working time coefficient of refrigerator (P 130)
6. Electrical calculation-① Draw equivalent circuit diagram (draw several pictures for several states); (2) according to the series and parallel connection, find out the equal relationship and proportional relationship; (3) Solution (note that current, voltage and electric power should take the same value)