What are the classic experiments in junior high school physics?

1.Measurement of length, estimation.

2 Measurement of density.

3 Reflection and refraction of light.

4 Experiments on friction, 5 Experiments on levers.

6 Determination of work.

7. Measurement of electric current.

8. Measurement of voltage.

9. Verification of the characteristics of series-parallel circuits.

10 Voltammetry.

11 Joule's Law.

12 Magdeburg Hemispheric Experiment.

13 Tori Pullari Experiment.

14. Electromagnetic induction.

**Experiments on the imaging law of convex lenses".

First of all, in the experiment of the imaging law of the convex lens, the flame of the candle, the convex lens, and the light screen should be adjusted to the same horizontal straight line, and according to the conjecture, the distance between the objects should be changed first, and several experiments should be carried out from large to small. Note: When looking at a virtual image, you should look to the left hand side of the light screen (usually this is the case).

**Characteristics of series circuits".

**Characteristics of series circuits".

Students' hands-on experiment: Connect the physical circuit according to scheme A and check whether the design scheme is correct.

Question: How many paths are there for a current in a series circuit?

Observation: Remove one of the bulbs after closing the switch small bulb and observe if the other bulb glows? (After the students do the hands-on operation, the teacher uses more ** demonstration).

Conclusion: There is only one path for the current in the series circuit, and the work of each electrical appliance in the series circuit should affect each other.

Characteristics of parallel circuits".

Hands-on experiment: Connect the physical circuit according to scheme B and check whether the design scheme is correct.

Question: How many paths are there for current in a parallel circuit?

Conclusion: There are two or more channels of current in the parallel circuit, and the work of the electrical appliances in the parallel circuit does not affect each other.

Magdeburg Hemispheric Experiment.

Tori Pully Experiment.

Electromagnetic induction.

Newton's First Law: Air Cushion Rails.

Verification of the parallelogram theorem.

Magdeburg Hemispheric Experiment.

Tori Pully Experiment.

Electromagnetic induction.

1. Observation.

It is a method for people to purposefully and systematically investigate the relevant things that appear in order to understand the nature and laws of things, and it is one of the common methods for collecting, obtaining, recording and describing materials.

2. Comparative Method.

It is the thought process and method of determining the differences and commonalities between the objects of study, and various physical phenomena and processes can be compared to determine their differences and commonalities.

3. Control variable method.

The relationship between the speed of evaporation and the temperature of the liquid, the surface area of the liquid, and the velocity of the air above the liquid was studied.

Scientific reasoning, also known as the ideal experiment method.

Ideal experiment: The so-called ideal experiment, also known as "imaginary experiment", "abstract experiment" or "ideological experiment", is an ideal process shaped by people in thought, a kind of logical reasoning thinking process and an important method of theoretical research.

Although the ideal experiment is also called an experiment, it is different from the real scientific experiment in principle, the real scientific experiment is a practical activity, while the ideal experiment is an activity of thinking, the former is an experiment that can be realized by the design through a physical process, and the latter is an experiment that people conceive in abstract thinking but cannot actually do.

However, the ideal experiment is not a subjective conjecture divorced from reality. First of all, the ideal experiment is based on practice, and the so-called ideal experiment is to grasp the main contradiction and ignore the secondary contradiction on the basis of the real scientific experiment to make a deeper abstract analysis of the actual process.

Secondly, the generalization process of ideal experiments is based on certain logical laws, which are summarized from long-term social practice and confirmed by practice.

Case study of whether a vacuum can transmit sound; Newton's first law, etc.

The top 10 classical physics chain acacia experiments are as follows:1. Eratosthenes measures the circumference of the Earth.

2. Galileo's free fall test.

3. Galileo's acceleration test.

4. Newton's prism decomposes sunlight.

5. Cavendish torsion scale test.

6. Thomas Young's light interference experiment.

7. Jean Foucault's pendulum test.

8. Robert Milligan's oil drop test.

9. Rutherford discovers nuclei.

10. Thomas Young's double-slit demonstration is applied to electron interference experiments.

Eratosthenes measured the circumference of the Earth:In the 3rd century B.C., in a small town called Aswa, Egypt, the midday sun of the summer solstice hung overhead. There is no shadow of the object, and the sun or lack shines directly into the well.

Eratosthenes realized that this could help him measure the circumference of the Earth. At the same time on the same day a few years later, he recorded the shadow of an object from the well of the city of Alexandria (just north of Aswa) on the same meridian.

It was found that the sun's rays were slightly off, at an angle of about 7 degrees to the vertical. The rest is a matter of geometry. Assuming the Earth is spherical, then its circumference should be 360 degrees.

If the two cities were to be divided into 7 degrees, it would be a circumference of 7,360, which was the distance of 5,000 Greek sports fields at that time.

Galileo's freefall test:Ranked second. At the end of the 16th century, everyone thought that a heavier object would fall faster than a smaller object, as the great Aristotle said.

Galileo Galilei, who was then working in the mathematics department of the University of Pisa, boldly challenged public opinion by throwing a light and heavy object from the leaning tower at the same time, allowing everyone to see both objects fall to the ground at the same time. He demonstrated to the world the invaluable spirit of respecting science without fear of authority.