For more information about junior high school and high school, you can get it on the Physics Master app and the Master 100 official account!
1. Learn about high school physics
Physics is a discipline that studies the basic laws of the structure and motion of matter.
It can be described in sixteen words: the mystery of the universe, the microness of particles, the movement of all things, and the complexity of daily use.
The mystery of the universe is the study of the past, present, future and how human beings use the resources of the universe.
The microscopic particle means that we do not only study the motion of matter on the macroscopic scale, but also study the motion of matter in the microscopic world that we cannot see, such as the nanotechnology proposed now, which studies the motion of matter on a scale of 10-9m.
The movement of all things says that everything is in motion, that motion is absolute, and that stillness is relative.
The meaning of daily use is that physics is closely related to our lives, and there are two important characteristics of physics:
1. Physics is a basic subject;
2. Physics is an important foundation of modern technology and plays an important role in promoting social development.
2. The difference between junior high school and high school physics
(1) Beginning and Medium
Knowing some basic concepts and basic laws
1. Mechanical movement: focus on learning uniform linear motion. Force: including gravity, elasticity, friction, two-force equilibrium condition, the same straight line two-force synthesis, Newton's first law is also known as the law of inertia.
2. Density; Pressure (including liquid internal pressure, atmospheric pressure. ）； buoyancy
3. Simple machinery: including lever, pulley, work, power; Energy and energy
4. Light: including the linear propagation of light, the reflection and refraction of light, and the imaging law of convex lens
5. Thermal: including temperature and internal energy
6. Series and parallel connection, electric energy and electric work of circuits; Magnetic fields, forces in magnetic fields, induced currents
(2) High school
1. Deepen understanding:
Example1
Junior High School – Just know that force is what changes the motion of an object
High School – To know how force changes the state of motion of an object
Example2
Junior – Faraday's law of electromagnetic induction tells us that cutting a magnetic inductance line with a closed wire will induce an electric current
High school - to know how to cut the size and direction of the induced current, there are Lenz's law, left and right hand rule.
2. Expand the scope
Mechanics (42%), Electricity (42%), Heat (6%), Optics (5%), Atomic Physics (5%)
(1) Mechanics mainly studies the relationship between force and motion. Emphasis is placed on Newton's laws of motion and mechanical energy.
Example 1: We're going to look at how a "tumbling roller coaster" works in a playground. Example 2: How fast do we want to shoot an object off the earth to become an artificial satellite?
(2) Electricity: mainly research electric field, circuit, magnetic field and electromagnetic induction. Focus on Ohm's law of closed circuits and the law of electromagnetic induction.
Junior high school electricity: It is assumed that the voltage at the two poles of the power supply is constant;
High School Electrical: Belief that the electrode voltage of a power supply is varied. This shows that the content of high school physics is deeper and wider than that of junior high school physics, and the qualitative analysis has changed to more quantitative analysis, and the learning has reached a new level, and students must be mentally prepared to overcome difficulties.
(3) Thermal: mainly studies the kinetic theory of molecules and the thermal properties of gases.
(4) Optics: mainly study the propagation law of light and the nature of light.
(5) Atomic physics: mainly studies the composition and change of atoms and nuclei.
(3) The main gradient of high school physics and junior high school physics
1. Stairway from scalar to vector.
The ladder from scalar to vector will take our understanding of physical quantities to a new level. In junior high school, we could only do algebraic operations, and we could only judge the change of a quantity numerically. Now it is required to use the algorithm of vectors, that is, to use the parallelogram law to operate, and when judging the change of vectors, we should not only look at the change in value, but also see whether the direction changes.
2. The concept of speed, junior high school defines speed as the ratio of distance and time, only size and no direction. Whereas, high school is defined as the ratio of displacement to time, which has both magnitude and direction. The pace of learning in middle school is actually an average rate.
Middle and High School Physics – "We Are Different"
01
The research problems of junior high school physics are relatively independent, while high school physics has a knowledge system. The first chapter starts with the description of motion and finds out the law of the change of the motion state of the object - acceleration. Chapter 2 Research on Linear Motion with Uniform Variable Speed. Chapter 3 introduces the characteristics of gravity, elasticity, and friction, as well as the synthesis and decomposition of forces. Chapter 4 Newton's Three Laws and Their Applications.
02
Middle school physics only introduces some relatively simple knowledge, while high school physics focuses on more in-depth research. For example, the motion of objects, junior high school only introduces the concept of velocity and average velocity, and high school has a deeper description of the concept of velocity, velocity is a vector, and the change of velocity must have acceleration, and the concept of acceleration is one of the most difficult knowledge points in high school.
03
Physics in junior high school focuses on qualitative analysis, while objects in high school focus on quantitative analysis. Quantitative analysis is more difficult than qualitative analysis and certainly more accurate. For example, for friction, junior high school only talks about ways to increase and decrease friction, which is easy to understand. In high school, the magnitude of friction is analyzed and calculated, and the magnitude of static friction is generally determined by the relative motion of the object.
High School Physics Study Tips
01
Focus on the analysis of physical processes
02
Pay attention to the use of images: The image method is a new method of analyzing problems, and its biggest feature is intuitive, which is very helpful for dealing with physical problems.
03
Attention should be paid to the cultivation of experimental ability and experimental skills, and high school physics experiments are divided into demonstration experiments and student experiments, which play an important role in learning and consolidating knowledge.
How to learn high school physics well
Preview before class. Preview the content to be learned in advance, and understand the important knowledge, difficulties and doubts through reading before class, so that you can listen to the lectures purposefully during class and improve learning efficiency.
01
Concentrate on the lesson. Listen carefully in class and not get distracted. Don't be self-righteous, ask the teacher for advice with an open mind, don't give up listening to the lecture because the teacher is simple, if this situation really happens, it can be regarded as review and consolidation.
02
Review in a timely manner. It is necessary to review and consolidate the knowledge learned in a timely manner. For the new knowledge that has just been learned in class, after class, we must review the whole process of its introduction, analysis, generalization, conclusion, application, etc., and compare it with the existing knowledge in the brain to see if there is any contradiction, if there is a contradiction, it means that it has not really been understood.
03
Do the questions independently. Independent thinking and solving problems may be slower, sometimes detours, and sometimes even unable to solve them, but these are normal and the only way for any beginner to succeed.
4
Troubleshooting. If you have any doubts or mistakes, you should write them down in a special notebook, and then solve them by thinking about them again or asking teachers and classmates.
5
Summary of the system. After learning each section, it is necessary to connect the knowledge points scattered in each chapter into a line, pave the surface, and form a network, so that the knowledge learned is systematic, regular, and structured, so that the association can be smooth and the thinking can be active.
6
Extracurricular learning. Read an appropriate amount of extracurricular books to enrich your knowledge and broaden your horizons. This is because different books and different authors will explain the problem from different angles and in different ways, and they can also deepen their understanding of physical concepts and laws from all aspects, and learn a lot of ingenious and simple ideas and methods for solving problems. Students can pay attention to the official account of "Physics Teaching Cloud", in which each small video introduces physics concepts to students, which is simple and clear.
7
The way of civil and martial arts, one by one. The study of high school physics courses must first be understood, and then remembered, practice will be done, gradually become proficient, practice makes perfect, and then innovate. Only by taking it step by step can we finally reach the highest level of learning physics.
As the old saying goes: Give a man a fish for only one meal, but teach a man to fish for a lifetime. Cultivate students' good study habits, so that students can get twice the result with half the effort in learning.
One of the questions that many junior high school students who are about to enter high school often ask is: Is there a connection between high school physics and junior high school physics? The following editor will sort out for prospective high school students, what are the learning content of high school physics and the content of junior high school physics learning.
Junior Optics
VS
High School Optics
| Beginning | high school |
| The law of refraction of light (qualitative understanding) When light is obliquely emitted from air into other media, the angle of refraction is less than the angle of incidence. When light is obliquely emitted into air from other mediums, the angle of refraction is greater than the angle of incidence. The three lines are coplanar, and the two lines are separated. | The Law of Refraction of Light (Quantitative Study) The sine of the angle of incidence is proportional to the sine of the angle of refraction, ie sinθ1/sinθ2=n, where n is the proportionality constant. The greater the constant n, the greater the angle at which the light rays are deflected from the air obliquely into this medium. |
| Convex lens imaging (Qualitative understanding) | Convex lens imaging (Quantitative research) Formation Formula: (1/u)+(1/v)=(1/f) |
| Dispersion of light (Refraction) | Dispersion of light (Thin Film Interferometry) |
Elementary and Middle Mechanics
VS
High School Mechanics
| Beginning | high school |
| Distance S | Displacement x |
| Gravity formula G=mg | Gravitation formula |
| frictional force (Qualitative understanding) | frictional force (Quantitatively calculated) f=μFN |
| Interaction forces | Newton's third law |
| Magnitude of inertia | Newton's second law |
| Aircraft bombing (Qualitative understanding) | Flat throwing motion (Quantitative research) |
| Fluid pressure with Flow velocity relationship (Qualitative understanding) | Bernoulli's equation (Quantitatively calculated) |
| Two forces are balanced | Multi-force balance |
| kinetic energy (Qualitative understanding) | Kinetic energy calculations (Quantitatively calculated) |
| Use strobe photos to understand the motion of objects | Measure speed with a dot timer |
| Gravitational potential energy (Qualitative understanding) | Gravitational potential energy calculation (Quantitatively calculated) |
| Leverage equilibrium conditions F1L1=F2L2 | Moment sum Moment balancing The product of the force and the arm is called the moment |
Junior high school electricity
VS
High School Electricity
| Beginning | high school |
| intercharged interaction (Qualitative understanding) | Calculation of the interaction force between charges (Quantitative research) |
| Supply voltage U | Power electromotive force E |
| Ohm's Law | Ohm's law for closed circuits |
| Voltammetry to measure resistance (Indirect measurement) | Ohmic meter to measure resistance (Direct Measurement) |
| Voltammetry to measure resistance (Error is not taken into account) | Voltammetry to measure resistance (Considering Errors) |
| An energized conductor is subjected to a force in a magnetic field (Qualitative) | Calculation of the force exerted by the magnetic field on the electric current (Quantitative) F=BIL |
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