1, the history of physics is a science that studies the laws and material structures of various physical phenomena such as light, heat, force, sound and electricity.

2. Observation and experiment are important sources to acquire physical knowledge.

3. The tool of length measurement is the scale, the international basic unit of length is the meter, and the symbol is m; Commonly used units are kilometer (km), decimeter (dm), centimeter (cm), millimeter (mm), micron (micron), nanometer (nm) and so on. The conversion relationship between them is

1 km =1000m lm=l0dm ldm=l0cm lcm=l0mm.

1 mm = 1 000 micron 1 micron = 1 000 nanometer.

4. The record of length measurement results includes accurate value, estimated value and unit.

5. Error: The difference between the measured value and the real value is called error. The reasons for the error are as follows: ① it is related to the person who measures it; ② Related to measuring tools. There are errors in any measurement results, which can only be minimized and cannot be absolutely avoided; But mistakes can be avoided.

Methods to reduce errors: ① Select more precise measuring tools; (2) adopting a more reasonable measurement method;

(3) Average the multiple measurements.

6. The tool for measuring time is a stopwatch, the international basic time unit is seconds, and the symbol is S; Common units include hours (h) and minutes (min). The conversion relationship between them is 1h=60min lmin=60s.

7. The main process of scientific inquiry is: asking questions, guessing and assuming, specifying plans and designing experiments, conducting experiments and collecting data, analyzing and demonstrating, evaluating, communicating and cooperating.

Chapter 2: Sound and Environment

1. Generation: Sound is generated by the vibration of objects. When the vibration stops, the sound stops; Sound source generated by object vibration and sound

2. Transmission: the transmission of sound needs medium, and vacuum cannot transmit sound. Sound propagates in the form of waves in the medium; The propagation speed is different in different media, generally the fastest in solid and the slowest in gas. At 15℃, the speed of sound propagation in air is 340m/s.

3. Three characteristics of sound:

(1) Tone: The pitch at which the human ear feels sound. Pitch is related to the vibration frequency of the vocal body. The higher the frequency, the higher the pitch.

(2) Loudness: the intensity of sound perceived by the human ear, and loudness is related to the vibration amplitude of the speaker; The greater the amplitude, the greater the loudness; Loudness is also related to the distance from the vocal body.

(3) timbre: Also called timbre, different vocalists produce different timbre.

4. Frequency determines pitch; Amplitude determines the loudness of sound. The unit of frequency is hertz, and the symbol is hertz. The frequency range of sound that people can feel is 20 Hz ~ 20Hz~20000Hz. People call the sound below 20Hz infrasound and the sound above 20000Hz ultrasonic. The application of ultrasound includes: ultrasonic lithotripsy, sonar detection of submarines and fish schools, and B-ultrasound examination of internal organs.

5. Music and noise:

Music: a pleasant sound; It is the sound that an object makes when it vibrates regularly.

Noise: a sound that is boring and harmful to physical and mental health; It is the sound that an object makes when it vibrates irregularly. People use decibels to grade the strength of dB sound.

6. Three methods to control noise are sound absorption, sound insulation and noise elimination; I.e. at the sound source, at the propagation path and at the receiver.

7. Use of sound: (1) Sound can convey information: for example, fishermen use sonar to detect fish.

(2) Sound can transmit energy: for example, some atomizers use ultrasonic waves to generate water mist.

8. Echo: The phenomenon that sound meets obstacles in the propagation path and is reflected back is called echo. If the echo reaches the human ear more than 0. 1s later than the original sound, the human ear can distinguish them, otherwise the echo will be mixed with the original sound to enhance the original sound. Stereo sound can be heard using binaural effect.

Chapter 3: Light and Eyes

First of all, the spread of light

1. Objects that can emit light by themselves are called light sources, such as the sun and fireflies. The moon is not a light source.

2. Light propagates in a straight line in the same uniform medium. Examples of linear propagation of light in life are solar eclipse, lunar eclipse, pinhole imaging, queuing aiming and so on.

The speed of light is the fastest in vacuum. The speed of light in vacuum is c=3.0× 108m/s, and the speed of light in different media is different.

Second, the color of light.

1. dispersion: the phenomenon that sunlight is decomposed into seven colors after passing through a prism, indicating that white light is not monochromatic light.

2. Three primary colors of color light: red, green and blue; The color of an opaque object is determined by the light it emits, and the color of a transparent object is determined by the light it transmits. The three primary colors of pigment are magenta, yellow and cyan.

Third, the reflection of light

1, light reflection law: reflected light is on the same plane as incident light and normal line, and reflected light and incident light are separated on both sides of normal line; The reflection angle is equal to the incident angle.

2. In the phenomenon of light reflection, the light path is reversible.

3. There are two kinds of light reflection on the surface of an object: one is specular reflection, and the reflecting surface is smooth, such as "reflection" on a blackboard; The other is diffuse reflection, and the reflecting surface is rough. For example, we can see non-luminous objects from different directions. Both specular reflection and diffuse reflection obey the law of light reflection.

4. Plane mirror imaging law: the virtual image of an object in a plane mirror, the size of the image and the object is equal, the connecting line between the image and the object is perpendicular to the mirror surface, and the distance from the image and the object to the mirror surface is equal.

5. Spherical mirrors include convex mirrors, such as rearview mirrors of cars and reflectors at road corners, which are mainly used to expand the field of vision; There are also concave mirror, such as solar cookers and flashlights, which are used to focus light.

Fourth, the refraction of light

1. Refraction of light: the phenomenon that light enters another medium from one medium and its propagation direction changes.

2. When light is obliquely incident from the air into other media such as water or glass, the refracted light is tricked into the normal direction, and the refraction angle is smaller than the incident angle. With the increase of incident angle, the refraction angle also increases.

When light obliquely enters the air from water or glass, the refracted light will be far away from the normal, and the refraction angle is greater than the incident angle. When light air is vertically incident on the surface of other media such as water or glass, the propagation direction remains unchanged, and the refraction angle is equal to the incident angle, which is equal to 0.

3. In the phenomenon of light refraction, the light path is reversible.

Verb (abbreviation for verb) invisible light.

The part of the spectrum other than red light is called infrared, which is used in infrared night vision devices and infrared thermometers; The part of the spectrum other than violet light is called ultraviolet light and ultraviolet money detector.

Six, lens and convex lens imaging

1, a convex lens with a thick center and a thin edge, can converge light.

2. A concave lens with a thin center and a thick edge has a divergent effect on light.

3. Focus of the convex lens: The light rays parallel to the main optical axis converge at a point after passing through the lens, which is called the focus of the convex lens and is represented by the letter "F".

4. The law of convex lens imaging and its application.

(1) focal length: denoted by the letter f, which refers to the distance from the focal point to the optical center; Object distance: expressed by the letter U, which refers to the distance from the object to the lens; Image distance: refers to the distance from the image to the lens, represented by the letter V.

(2) convex lens imaging rules and application list

Property application of object distance u image distance v image

U & gt2ff & ltu & lt2f Inverted Miniature Real Image Camera

U = 2f u = 2f Invert the real image.

F<u & lt2fu & gt 2f real-image projector with reverse amplification.

U<f vertical magnifying virtual image magnifying glass

(1) The camera is made by using the principle that the object distance is more than twice the focal length, and the inverted image is restored to the real image.

② The projector is made by using the principle that the object distance is greater than 1 times and the focal length is less than 2 times, and the real image is inverted and enlarged.

(3) The magnifying glass is made by using the principle that the object distance is less than 1 multiple focal length, and it becomes an upright magnified virtual image.

Seven, eyes and lenses

1, the function of the eye is equivalent to a convex lens, and the eyeball is like a camera. The light emitted by the object converges on the retina to form an inverted and reduced real image.

2. The reason for myopia is that the lens is too thick, the refractive power of the eye is too strong, or the eye axis is too long, and the light emitted by the object becomes in front of the retina. Myopia needs to be corrected by wearing concave lenses.

3. The reason for hyperopia is that the lens is too thin, the refractive power of the eyes is too weak, or the eye axis is too short, and the light emitted by the object becomes behind the retina. Myopia needs to be corrected by wearing a convex lens.

Chapter four: the substances around us.

1. mass: the amount of substance contained in an object is called mass, which is represented by the symbol m, and the mass will not change with the change of the position, shape and state of the object.

2. The international unit of mass is kilogram, and the symbol is kilogram. Commonly used units are tons (t), grams (g), milligrams (mg) and so on. The conversion relationships are 1t= 1000kg, 1kg = 1000mg, 1g= 1000mg.

3. Tools for measuring quality: too common for measuring quality in the laboratory. Commonly used tools are platform scales, scales and electronic scales.

4, using the tray balance method to measure the quality of the object:

(1) Before weighing, put the balance on a horizontal workbench, move the travel code to the zero scale at the left end of the balance, and adjust the balance nuts at both ends of the beam until the pointer is in the center of the dial, and the balance will be balanced.

(2) When weighing, put the measured object on the left board and the weight on the right board. Use tweezers when lifting weights.

(3) When reading, the mass of the measured object is equal to the mass of the weight plus the mass of the scale corresponding to the stray code.

5. Density: The mass per unit volume of a substance is called the density of the substance, which is represented by the symbol ρ. Every substance has a certain density, and the density of different substances is generally different. The density of a substance has nothing to do with the mass, volume, shape and position of the objects that make up the substance, but it is related to the kind, temperature and state of the substance.

2. Density formula: ρ=m/v in kg/m3 (kg/m3). Common units are grams per cubic centimeter (g/cm3) and so on. The conversion relationship between them is1kg/m3 =1x10-3g/cm3.

6. Measurement of object density

(1) Measurement of General Solid Density

① Measure the mass of an object with a balance; ② Inject a proper amount of water into the measuring cylinder and record the volume of water (v1); (3) Tie the solid with a thin thread and put it into the water of the measuring cylinder, so that it is completely immersed in the water, and record the volume v2 of the water and the solid; ④ According to the measured data, calculate the density of solid with ρ = m/v. ..

(2) Measurement steps of liquid density

① Put a certain amount of liquid into a beaker, and measure the total mass of beaker and liquid M 1 with a balance; ② Pour a part of the liquid in the beaker into the measuring cylinder, and record the volume V of the poured liquid; ③ Measure the mass m2 of beaker and residual liquid with a balance to find out the mass of liquid poured into the measuring cylinder; ④ Calculate the liquid density of ρ=m/v according to the measured data.

Chapter V Matter, New Materials, Particles and the Universe

I. Physical characteristics of matter

1, all objects are composed of molecules, and various substances have many different properties. Such as the magnetism of matter, the conductivity of matter, particles and the universe.

1, molecule: the substance is composed of molecules, and the molecular diameter is10-10m = 0.1nm.

2. Atoms: Molecules are composed of atoms, atoms are composed of nuclei and electrons outside the nuclei, nuclei are composed of protons and neutrons, and protons and neutrons are composed of smaller particle quarks.

3, the law of gravity: 1687 Newton, a great scientist, found that there is a force of mutual attraction between any two objects, which is the law of gravity. The magnitude of gravity is related to the mass of objects and the distance between objects.

4. Light-year is a unit of length in astronomy, indicating the distance that light travels in a year. =9.4605× 10 15m

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