I want to summarize physics in the eighth grade

Grade 8 Physics Content: Chapter 1 is mechanical motion, including the measurement of length and time, the description of the speed of motion, and the experiment of measuring the average speed; The second chapter is on acoustic phenomena, including the production of sound, the characteristics of sound, the generation and harm of noise; Chapter 3 is the change of state of matter, including temperature, melting and solidification, vaporization and liquefaction, sublimation and condensation; Chapter 4 is the phenomenon of light, Chapter 5 is lens, and Chapter 6 is mass and density.

Grade 8 Physics Learning Strategy

1. Proactive learning. In the classroom, the brain should run at a high speed, and you should consider some problems caused by the teacher's chain, and don't wait for the teacher to "indoctricate". After class, don't just be satisfied with completing the tasks assigned by the teacher, such as preview, review, homework, and small experiments, but take the initiative to arrange the learning content and time reasonably according to your own reality.

2. Cultivate the habit and ability to think independently. In learning, we should be good at asking questions, expressing our own opinions, and at the same time learning to sort out and reintegrate knowledge, organize and systematize messy knowledge, and turn it into our own things. For example, after each chapter, try to summarize its main content in two or three hundred words.

3. The study of physics in the eighth grade does not require one step, and it is just the second year of junior high school to "aim" at the high school entrance examination, and do a lot of questions similar to the questions of the high school examination, which will not only not improve the ability, but will affect their understanding of the basic concepts and basic laws.

4. In the process of observing classroom demonstration experiments and conducting student experiments, we should pay attention to cultivating our ability to identify equipment and instruments, and consciously analyze the existing problems in the case of too large experimental errors, and improve the experiments to reduce the errors.

Physics

Physics is the study of the most general laws of motion of matter and the basic structure of matter. As a leading discipline of natural science, physics studies the most basic forms and laws of motion of all matter, from the cosmic vibrator to the elementary particles, so it has become the research foundation of other natural science disciplines. Physics is an experimental science, and it is also a science that advocates rationality and attaches importance to logical reasoning.

Physics makes full use of mathematics as its working language, and it is one of the most sophisticated natural sciences today.

1. Light energy travels in a vacuum, and sound cannot propagate in a vacuum

2. Light is an electromagnetic wave, and electromagnetic waves can propagate in a vacuum.

3. The speed of light in a vacuum: c = 3 108m s = 3 105km s (the speed of electromagnetic waves is also this).

4. In the description of the law of reflection, the reflection should be said first, and then the incidence should be said (plane mirror imaging is also said"Images and things"order).

5. Every ray of light in specular reflection and diffuse reflection obeys the law of reflection of light.

6. The reflection phenomenon of light (people looking in the mirror, reflection in water).

8. The glass plate of the plane mirror imaging experiment should be placed perpendicular to the horizontal tabletop.

8. People are far away from the plane mirror, and the image of the person in the mirror becomes smaller (wrong, unchanged).

1. The propagation of light can shine and is called a light source, and the moon is not the sun. The propagation of light is conditional, and the homogeneous medium is straight.

2. The reflection of light The normal passes through the incident point, and the dotted line reflects perpendicular to the surface. The reflected incidence is on both sides, and the reverse angle of entry is always equal. The angle included in the method is the entry angle, and the entry angle increases and the reverse angle increases. All objects are reflected, specular reflection diffuses the opposite side.

3. Plane mirror imaging Plane mirror, into a virtual image, the size is equal and symmetrical. The image of the object to the mirror distance is trapped, etc., they are connected to the mirror surface. The reflection of the graph is inversely extended, and the intersection point of the dashed line is the image point. All image points form an image, and the virtual image should be represented by a virtual image.

4. Refraction of light Light enters from one object to another, and reverses and refractions occur at the same time. The diagonal line is close to the water to be refracted, and the polyline is close to the normal. The normal is perpendicular to the interface, and the polyline incoming line is divided into two sides.

The light in the water obliquely enters the air, the broken line is far from the normal, the trees become taller underwater, and the fish become shallower on the shore.

5. The dispersion of light, red, orange, yellow, green, blue, indigo, violet, white light, dispersion of seven colors. The color light is red, green and blue, and the pigment is red, blue and yellow. Red objects reflect red light, and other colors of light are absorbed. There is no reflected light into the eye, and one piece is black.