Chapter 1 Sound Phenomenon 1.

Production of Sound: Sound is produced by the vibration of objects.

2.

Propagation of sound: (1) The propagation of sound requires a medium.

Sound can propagate in solids, liquids, and gases, but it does not propagate in vacuum.

(2) Sound travels faster in solids and liquids than in air.

(3) The propagation speed of sound in air at 15℃ is 340m/s.

3.

Characteristics of sound: pitch, loudness, timbre.

(1) Pitch: Pitch is related to the speed of vibration of the sound-emitting body.

If an object vibrates quickly, the pitch will be high; if it vibrates slowly, the pitch will be low.

(2) Loudness: The intensity of sound is called loudness.

The greater the amplitude of the vibration of an object, the louder the sound produced.

(3) Timbre: Different sound-emitting bodies have different materials and structures, and the timbre of the sound is also different.

Chapter 2 Light Phenomenon 1.

Law of linear propagation of light: Light propagates in a straight line in the same homogeneous medium.

2.

The speed of light in vacuum: 3×108m/s.

3.

Reflection of light: (1) Concept: When light hits the surface of any object, part of the light will always be reflected back by the surface of the object. This phenomenon is called reflection of light.

(2) Several terms: ①Angle of incidence: The angle between the incident light and the normal is called the angle of incidence.

②Reflection angle: The angle between the reflected light and the normal is called the reflection angle.

(3) The law of reflection of light: reflected light, incident light, and normal are in the same plane; reflected light and incident light are on both sides of the normal; the reflection angle is equal to the incident angle.

(4) Types of reflection: specular reflection, diffuse reflection.

①Specular reflection: The reflection that occurs on a smooth mirror surface is called specular reflection.

When parallel light is specularly reflected, the reflected light is still parallel light, but the propagation direction has changed. Since the reflected light is in the same direction, it is very dazzling when viewed from this direction, but cannot be seen from other directions.

Reflect light.

②Diffuse reflection: The reflection that occurs on a rough surface is called diffuse reflection.

After diffuse reflection of parallel light, the reflected light is no longer parallel, but shoots in all directions according to the law of reflection. Since the reflected light shoots in all directions, the reflected light can be seen from different directions, and the light is not dazzling.

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(5) The reason why we can see objects that do not emit light themselves: the light reflected by the object enters our eyes.

4.

Imaging characteristics of a plane mirror: the object forms a virtual image in the plane mirror; the size of the image and the object are equal; the line connecting the image and the object is perpendicular to the mirror surface; the distance between the image and the object to the mirror surface is equal.

5.

Real image and virtual image: Difference Concept Can a light screen be used to undertake it? Inverted and upright Examples Real image The image formed by the convergence of real light rays Can Generally be inverted Small hole imaging Virtual image Composed of the intersection of the reverse extension lines of light No Generally upright Plane mirror imaging 6.

Refraction of light: (1) Concept: When light is incident obliquely from one medium into another medium, the propagation direction is deflected. This phenomenon is called refraction of light.

(2) Refraction angle: The angle between the refracted ray and the normal is called the refraction angle.

(3) Law of refraction: the refracted ray, the incident ray, and the normal are on the same plane; the refracted ray and the incident ray are on both sides of the normal; when light slants from air to water or other transparent substances, the refraction angle is smaller than the incident angle, and the light passes from

When a transparent substance such as water strikes air obliquely, the angle of refraction is greater than the angle of incidence.

7.

The optical path is reversible: In the reflection and refraction phenomena of light, the optical path is reversible.

8.

The reasons why transparent and opaque objects have different colors: (1) The color of a transparent object is determined by the colored light that passes through it; (2) The color of an opaque object is determined by the colored light that it reflects.

Chapter 3 Lens 1.

Convex lens and concave lens: (1) A lens that is thick in the middle and thin at the edges is called a convex lens; (2) a lens that is thin in the middle and thick at the edges is called a concave lens.

2.

Focal length: The distance from the focus to the optical center is called focal length.

3.

The effects of convex lenses and concave lenses on light: (1) Convex lenses have a convergent effect on light; (2) Concave lenses have a divergent effect on light.

4.

Lenses in life: The main component of cameras, projectors, and magnifying glasses is a convex lens.

5.

The rules of convex lens imaging: the nature of the object distance u image application inverted size virtual real u>2f inverted reduced real image camera 2f >u>f inverted amplified real image projector u< f upright amplified virtual image magnifying glass Chapter 4 Changes in the state of matter 1.

Temperature: (1) Concept: The degree of hot or cold of an object is called temperature.

(2) Unit of temperature: °C.