What other methods are used in physics besides the control variable method?

Modeling Methods Representing abstract physical phenomena with simple and understandable concrete models. For example, a model of the solar system is used to represent the structure of atoms, and simple lines are used to represent levers.

Superposition method in physics is often small, not easy to measure the same physical quantities superimposed on each other, after the measurement of the average method is commonly known as "superposition method", such as a centimeter scale the thickness of a piece of paper, the diameter of a copper wire and so on.

Controlled variable method The phenomena occurring in nature are often intricate and complex. The factors that determine the emergence and change of a phenomenon are often also many. In order to find out the causes and laws of change, we must try to control one or more of these factors with artificial methods, so that it remains unchanged, and then to compare, study the relationship between the other two variables, the scientific method of this research problem is the "control of variables method". Most of the junior high school physics experiments use this method, such as the current through the conductor I by the conductor resistance R and its ends of the voltage U, in the study of the relationship between the current I and the resistance R, the need to keep the voltage U unchanged; in the study of the relationship between the current I and the voltage U, the need to keep the resistance R unchanged.

Experiment + reasoning method There are a number of physical phenomena, due to experimental conditions, can not be directly verified, we need to conduct experiments, and then reasonably reasoning to reach the correct conclusion, which is also a common scientific method. Such as an alarm clock in a sealed glass enclosure, when the air is removed from the enclosure, the clock becomes smaller, and thus reasoning: the vacuum can not transmit sound; and then Newton's first law deduction

Conversion method Some invisible, unable to touch the physical phenomena, not good to recognize it directly, we often see them according to their manifestations, the phenomenon of touch to recognize them indirectly. Such as the thermal effect of the current to recognize the size of the current, according to the magnetic field on the magnet to recognize the role of the magnetic field and so on.

Equivalence method in the study of physical problems, sometimes in order to simplify the problem, commonly used a physical quantity to replace all other physical quantities, but will not change the physical effect. For example, the combined force is used to replace the individual component forces, the total resistance is used to replace the individual component resistances, and the buoyancy force is used to replace the individual pressures of a liquid on an object.

Descriptive method In order to study the convenience of the problem, we often use lines and other means to describe a variety of invisible phenomena. Such as the use of light to describe light, magnetic lines of magnetic induction to describe the magnetic field, the force of the graphic description of force, etc..

Analogy In recognizing some of the physical concepts, we often familiar with it and life with **** the same characteristics of the phenomena for analogy, to help us understand it. Such as recognizing the size of the current, with water flow for analogy. Recognize the voltage, with the water pressure to make an analogy.