(People's Education Edition) Review Outline of the Second Volume of Grade Seven, Science, Chinese, Mathematics, English, Social and Ideological and Political Education.

1 chapter environmental awareness review outline

First, feel the world.

1, sensory function of skin:

(1) What sensory functions does the skin have? (cold, hot, touch)

(2) Which part of the skin is sensitive to touch and heat? (Finger, back of hand)

(3) The skin of the human body does not feel the temperature, but feels the loss and gain of heat from the skin of the human body.

(4) What do these feelings mean to human beings? (protection)

Step 2 smell

(1) How is the sense of smell formed? (Nasal cavity-olfactory nerve endings of nasal mucosa-olfactory nerve-olfactory center of cerebral cortex forms sense of smell)

(2) Characteristics of sense of smell: ① It is easy to get tired; ② Animals are different; ③ The sensitivity of smell is related to age; ④ Animals have different sensitivities to the smells of different substances.

3. Taste:

(1) The formation of taste: the taste cells in the taste buds on the tongue-the taste nerve-the taste center of the cerebral cortex.

(2) Taste cells in taste buds are particularly sensitive to the stimulation of liquid substances.

(3) Different parts of the tongue have different sensitivities to sweetness, sourness, bitterness and saltiness. Tip of the tongue-sweet; Tongue root-bitter taste; Between the sides of the tongue-acid; The front parts on both sides of the tongue-the most sensitive to salty taste.

(4) What is the function of rinsing with clear water?

(5) Is taste related to smell? (Smell affects taste)

Second, the occurrence and spread of sound.

1. Sound generation: The vibration of objects (including solids, liquids and gases) produces sound. (able to judge or illustrate)

2. Sound propagation: Sound propagation needs medium, and solid, liquid and gas can all propagate sound (experimental proof can be designed or experimental conclusion can be analyzed). Vacuum can't transmit sound.

3. The form of sound propagation: sound wave.

4, the speed of sound propagation:

In the air of (1) 15℃, sound travels 340 meters per second.

(2) At the same temperature, the sound propagation speed is: solid is greater than liquid, and gas is greater than gas.

(3) In air, the speed of sound propagation increases with the increase of temperature.

(4) Echo is formed by sound reflection.

Third, ears and hearing.

1, ear structure and hearing formation

(1) ear structure: (can tell the structure of external ear, middle ear and inner ear) The cochlea is an auditory receptor; The semicircular canal and vestibule can feel the change of head position.

(2) The formation process of hearing: sound-external auditory canal-tympanic membrane (producing vibration)-auditory bone (amplifying sound)-cochlea-auditory nerve-auditory pathway of cerebral cortex.

(3) Hearing protection: Open your mouth when encountering loud noise.

(4) Why do you listen with two ears? (Related to identifying the direction of sound source)

2. Tone, loudness and timbre

(1) sound level is called tone.

① Tone is determined by frequency (the number of times an object vibrates within 1 s).

② The range of sound that most people can hear is about 20 ~ 20000Hz. What are ultrasonic waves and infrasound waves? )

(2) Loudness: the sound intensity that people feel subjectively.

(1) The loudness of sound is related to the vibration amplitude of sound source and the distance between people and sound source.

② Loudness is usually measured in decibels.

(3) timbre: It is related to the nature, shape and method of sound production.

3. Noise pollution

What are the effective measures to control noise pollution?

Fourth, light and color.

1. What is a light source? (luminous object)

2, the spread of light

(1) Light travels in a straight line in the same homogeneous medium.

Examples: examples and applications of straight-line propagation of light (solar eclipse, lunar eclipse, shadow formation, shooting, queuing, etc. )

3. How fast does light travel?

The propagation speed of light in vacuum

What is the physical unit of light years?

How do circular spots form in the shade of the sun?

4. Scattering of light

(1) Composition of sunlight (red, orange, yellow, green, blue, indigo and purple)

(2) Is the sun monochromatic?

5. Invisible light

The relationship between infrared rays, ultraviolet rays and human beings

6, the color of the object

What determines the color of transparent objects; (the colored light he can penetrate)

The color of an opaque object is the same as the color of reflected light, and it absorbs the color light different from the color of the object.

Example: What color is the red light on green paper?

Verb (abbreviation for verb) Reflection and refraction of light.

1, light reflection law: three lines * * * plane; Second-line separation; These two angles are equal (the reflection angle is equal to the incident angle).

2. The imaging law of plane mirror: equidistant and vertical virtual images; The line between the image and the object is perpendicular to the plane mirror.

3. What are the effects of convex mirror and concave mirror on light (divergence and convergence)?

4. Refraction of light

(1) refraction law: three lines * * * plane; Second-line separation; When the light obliquely enters other substances from the air, the refraction angle is smaller than the incident angle.

(2) Examples and applications: light pollution in cities; Rainbow; Phantom; People on the shore look at the objects in the water, and the objects become shallow; Divers in the water look at the objects on the shore and the objects get taller.

Six, eyes and vision

1, lens:

Determination of (1) convex lens and concave lens

(2) Influence of convex lens and concave lens on parallel light (convergence and divergence)

2. The law of convex lens imaging

U & gt2f, it looks like

u=2f v？

2f & gtu & gtf

u & ltf

3. Camera and magnifying glass

(1) camera: u >；; 2f

I want to change my half-length photo to a full-length photo. How to adjust it?

(2) Magnifier: U

How to adjust the position of the magnifying glass to get a magnified and positive image?

(3) projector 2f >；; u & gtf

How to resize the text on the screen?

(3) convex lens in life

4. Eyes:

(1) Refractive system in eyeball: cornea, aqueous humor, lens and vitreous body.

(2) The formation process of vision: the visual center of retina, optic nerve and cerebral cortex.

(3) the relationship between pupil change and light intensity

Why does strong sunlight feel particularly dark when it enters a room?

5. Limitations of human vision

(1) viewpoint and blind spot test

(2) Causes and correction of myopia and hyperopia.

The main cause of myopia is that the anterior and posterior diameter of eyeball is too long or the curvature of lens is too large, and the light from far away focuses in front of retina; You need to wear concave lenses.

The main reason of hyperopia is that the anterior and posterior diameter of eyeball is too short or the elasticity of lens becomes smaller, and the light from near is focused behind retina; Need to wear a convex lens.

(It is required to be able to judge according to the diagram)

(3) color blindness

6. Take care of your eyes and protect your eyesight.

"two want two don't"; External causes of unexpected situations

7. Microscopes and telescopes

Review outline of "Sports and Strength"

I. Reference objects

1. Definition: An object assumed to be stationary for studying its motion is called a reference object.

2. Any object can be used as a reference, and the reference is usually selected according to the convenience of studying the problem. For example, when studying the motion of objects on the ground, the ground or objects fixed on the ground are often selected as reference objects, in which case the reference objects can be omitted.

3. Choosing different reference objects to observe the same object may lead to different conclusions. Whether the same object is moving or static depends on the selected reference object, which is the relativity of motion and static.

You can't choose the research object itself as the reference object, so the research object is always static.

Exercise:

☆ The poem "Seeing the Tathagata meet, watching the mountain like a boat", in which the reference objects of "Seeing the Tathagata meet" and "boating" are the ship and the mountain respectively.

☆ The passengers sitting in the eastbound A car saw the trees on the roadside retreating, and at the same time saw the B car retreating from the A car. Try to explain the action of the B car.

There are three situations: ① Car B does not move; ② Car B moves eastward, but the speed is not as fast as that of car A; ③ The B car is heading west.

☆ Explain Mao Zedong's poem "Sitting on the ground and traveling 80,000 miles a day, patrolling the sky and watching the sea" in Seeing the Worried God.

The first sentence: Taking the center of the earth as a reference, the ground turns 80,000 miles around the center of the earth. The second sentence: Take the moon or other celestial bodies as a reference, and you can see many rivers on the earth here.

Second, the mechanical movement

Definition: In physics, the change of object position is called mechanical motion.

Features: Mechanical motion is the most common phenomenon in the universe.

The method of comparing the speed of objects;

(1) Compare the speed of pedestrians and cyclists who start at the same time: the same time, the longer the distance, the faster the movement.

⑵ Compare the speed of 100-meter athletes: The shorter the distance, the faster the movement.

(3) The speed of1000 meter runner is faster than that of 10000 meter runner. This method is often used to compare the speed of an object in practical problems and to describe the speed of motion in physics.

Exercise: In physical education class, students A, B and C run 100 meter. Their scores were 14.2S, 13.7S and 13.9S respectively, and the student won the first place. The easiest way to compare the speed of three races here is to run faster in the same time.

Classification: (according to the movement route) (1) curve movement; (2) linear motion.

ⅰ uniform linear motion:

Definition: the speed is constant, and the motion along a straight line is called uniform straight line motion.

Definition: In uniform linear motion, the speed is equal to the distance traveled by the moving object in unit time.

Physical meaning: Speed is a physical quantity representing the speed of an object.

Calculation formula: deformation,.

Speed unit: m/s in the international system of units; Unit kilometer/hour in transportation; Of the two units, the m/s unit is larger.

Conversion: 1m/s = 3.6km/h People's walking speed is about 1. 1m/s, and its physical meaning is that when people walk at a constant speed, they move within 1.1m.

Direct measuring tool: speedometer.

Speed image:

Ⅱ variable speed movement:

Definition: Motion with variable speed is called variable speed motion.

To find the average speed of a certain distance, we must find the distance and the corresponding time.

Physical meaning: indicates the average speed of variable speed movement.

Measurement of average speed: principle.

Methods: Measure the distance with a balance and the time with a stopwatch. A car that slows down on an incline. Set the upper half and the lower half, and the average speed of the whole journey is v 1.v2.v, then v2>v>v 1.

Common sense: people's walking speed is1.1m/s; Bicycle speed is 5m/s; The speed of a jumbo jet is 900 km/h; Passenger train speed is140km/h; High-speed vehicle speed108 km/h; The speed of light and radio waves is 3x108m/s/s.

Ⅲ. Recording of data in the experiment:

Designing data record forms is one of the basic abilities that junior high schools should have. When designing a table, it is necessary to find out the quantities directly measured and calculated in the experiment, and then find out the number of groups of data to be recorded as rows and columns of the table. You can design a reasonable table according to your needs.

Exercise:

In a middle-distance race test, Xiaoming ran 1000m and Xiaohong ran 800m m. It was found that the time for them to finish the two games was 4 minutes, 10 seconds and 3 minutes and 20 seconds respectively. Please design a record form and record their running distance, time and average speed in the form.

Solution: The table design is as follows

Time average speed of running distance

Xiao Ming 1000 m 4 min 10 sec 4 m/s

Xiaohong 800 m 3 min 20 s 4 m/s

Third, length measurement.

1. Length measurement is the most basic measurement in physics and the basic skill of scientific inquiry. A common tool for measuring length is a scale.

2. In the international system of units, the main unit of length is m, and commonly used units are kilometer (km), decimeter (dm), centimeter (cm), millimeter (mm), micron (micron) and nanometer (nm).

3. Conversion relationship between main unit and common unit:

1k m = 103m； 1m = 10dm； 1dm = 10cm； 1cm = 10mm； 1mm = 103 μm； 1m = 106 μm； 1m = 109nm； 1μm= 103nm .

The process of unit conversion: Formula: "Constant coefficient, equivalent substitution".

4. Length estimation: the blackboard length is 2.5m；; The height of the desk is 0.7m；; Basketball diameter is 24cm；; Nail width1cm; Pencil lead diameter is1mm; ; The length of a new pencil is1.75dm; ; Palm width1DM; The height of the ink bottle is 6 cm.

5. Special measurement methods:

A. When measuring tiny quantities such as the diameter of thin copper wire and the thickness of a piece of paper, the accumulation method is commonly used (when the measured length is small and the accuracy of the measuring tool is not enough, smaller objects can be accumulated, and then a single length can be obtained after measuring with a scale).

☆ How to measure the thickness of a piece of paper in physics textbooks?

Answer: Count the pages of physics textbooks, write down the total number of pages n, and measure the thickness L of n pieces of paper with millimeter scale, then the thickness of a piece of paper is L/N. ..

☆ How to measure the diameter of thin copper wire?

Answer: The thin copper wire is tightly wound around the pencil shaft for N turns to form a solenoid, and the length L of the solenoid is measured with a scale, so the diameter of the thin copper wire is L/N. ..

☆ Two coils of thin copper wire, one of which has a diameter of 0.3mm, and the label on the other has fallen off. If you are only given two identical new pencils, can you find out its diameter more accurately? Write the calculation process and mathematical expression of the diameter of thin copper wire.

Answer: Two coils of thin copper wire with known diameter and unknown diameter are tightly wound on two identical new pencils, and the coil lengths are equal. Write down the winding numbers N 1 and N2, and the diameter D2 of the unknown copper wire can be calculated as 0.3n1/n2mm.

B, measure the distance between two points on the map, the circumference of the cylinder, etc. , often converted to straight line method (mark the starting point and ending point on the curve that is not easy to stretch, and then straighten it).

☆ Given a soft copper wire and a scale, can you estimate the railway length from Beijing to Guangzhou with the atlas?

Answer: Concentrate the railway line from Beijing to Guangzhou with a thin copper wire lap diagram, then straighten the thin copper wire, measure the length L with a scale, find out the scale and calculate the length of the railway line.

C, measuring the length of the playground runway and other common wheel rolling methods (use a wheel with a known circumference to roll along the curve to be measured, write down the number of turns of the wheel, and calculate the length of the curve).

D, commonly used auxiliary methods for measuring the diameter cone of coins, balls and cylinders (for the length of objects that cannot be measured directly with the scale, it can be measured in combination with the scale triangle).

How many ways can you think of to measure the diameter of a coin? (Introduction)

(1) Ruler Triangle Auxiliary Method; (2) Cut the edge of the folded coin with strokes, then fold it in half, and measure the crease length; (3) measure the circumference to find the diameter of the coin when it rolls on the paper once; (4) Put the coin flat on a ruler and read the length between two scale lines tangent to the left and right of the coin.

6. Rules for the use of scales:

A. [Selection]: Select the scale according to actual needs.

B. "Observation": Before using the scale, observe its zero scale line, measuring range and dividing value.

C, "put" when measuring the length with the scale, the scale should follow the measured straight line (close to the object, not skewed). Do not use worn zero score lines. (When measuring an object with a scale worn by the zero line, start from the whole scale)

D. "Look": When reading, the line of sight should be perpendicular to the ruler.

E. "Reading": In accurate measurement, it is necessary to estimate the next digit of the scale value.

F "Note": The measurement result consists of numbers and units. (It can also be expressed that the measurement result consists of accurate value, expected reading and unit).

Exercise: Two students measure the length of the same pen. The result of A is 12.82 cm, and the result of B is 12.8cm. If there is no error in the measurement of two students, the reason for the difference is that the scale values of the two scales are different. If the scales used by these two students are both mm, then the result of student B is wrong. The reason is that there is no estimated value.

7. Error:

(1) Definition: The difference between the measured value and the real value is called error.

(2) Reason: The measuring tools measure human factors in the environment.

(3) Methods to reduce the error: measure the average value for many times; With more complicated instruments.

(4) Errors can only be reduced and can't be avoided, and errors caused by subjective carelessness can be avoided if the rules for using measuring instruments are not observed.

Fourth, the measurement of time.

1. Unit: seconds.

2. Measuring tools: ancient: sundial, hourglass, drip, pulse, etc.

Modern: mechanical clock, quartz clock, electronic watch, etc.

Five, the role of force

1. The concept of force: force is the action of an object on an object.

2. Conditions for force generation: ① There must be two or more objects; ② There must be interaction (no contact) between objects.

3. The essence of force: the forces between objects are mutual (in any case, the mutual forces are equal in size and opposite in direction, acting on different objects). When two objects interact, the force applying object is also a force applying object, and vice versa.

4. The function of force: Force can change the motion state of an object; Force can change the shape of an object.

Note: Whether the motion state of an object changes generally refers to whether the speed of the object's motion changes (the change of speed) and whether the direction of the object's motion changes.

5. Unit of force: In the international system of units, the unit of force is Newton, abbreviated as cow, and represented by N. ..

Perceptual knowledge of force: the force used to take two eggs is about1n.

6. Force measurement:

⑴ Dynamometer: a tool for measuring force.

⑵ Classification: spring dynamometer and grip dynamometer.

(3) Spring dynamometer:

A. Principle: Within the elastic limit, the elongation of the spring is directly proportional to the pulling force.

B. Usage: "Look": whether the measuring range, dividing value and pointer refer to zero; "adjustment": zero adjustment; "Reading": reading = tick stress.

C. Note: The force applied to the spring dynamometer shall not exceed its maximum range.

D in physical experiments, the size of some physical quantities is not suitable for direct observation, but when it changes, it is easy to observe the changes of other physical quantities. It is an idea of making measuring instruments to display the quantities that are not suitable for observation with those that are easy to observe. This scientific method is called transformation. Instruments made by this method: thermometer, spring dynamometer, pressure gauge, etc.

7. The three elements of force: the size, direction and action point of force.

8. Representation of force: Schematic diagram of force: Use line segments with arrows to represent the magnitude, direction and action point of force. If there is no order of magnitude, it does not mean that the greater the force, the longer the line segment in the same picture should be.

Inertia and inertia law of intransitive verbs

1. Galileo inclined plane experiment;

The purpose of the three experiments is to ensure that the car starts to move along the plane at the same speed.

⑵ Experimental conclusion: Under the same conditions, the more stable the plane is, the farther the car will go.

(3) Galileo's inference is that in an ideal situation, if the surface is absolutely smooth, the object will always move at a constant speed.

(4) The excellence of Galileo's inclined plane experiment lies not in the experiment itself, but in the unique method used in the experiment-idealized reasoning based on the experiment. It marks the real beginning of physics.

2. Newton's first law:

(1) Newton summed up the research results of Galileo, Descartes and others, and obtained Newton's first law, the content of which is that all objects always keep still or move in a straight line at a constant speed when they are not affected by external forces.

(2) Description:

A, Newton's first law is based on a large number of empirical facts, summed up through further reasoning, and has withstood the test of practice, so it has become one of the basic laws of mechanics recognized by everyone. But there can be no force around us, so it is impossible to prove Newton's first law directly through experiments.

B, the connotation of Newton's first law: an object is not stressed, the original static object will remain in a static state, and the original moving object will move in a straight line at a constant speed no matter what it does.

C. Newton's first law tells us that an object can move in a straight line at a uniform speed without force, that is, force has nothing to do with the state of motion, so force is not the reason for producing or maintaining motion.

3. inertia:

⑴ Definition: The property that an object keeps its state of motion unchanged is called inertia.

⑵ Description: Inertia is an attribute of an object. All objects have inertia under any circumstances, and the size of inertia is only related to the mass of the object, and has nothing to do with whether the object is stressed, whether it is stressed, whether it is moving or not, and the speed of movement.

4. The difference between inertia and inertia law:

A. Inertia is an attribute of the object itself, and the law of inertia is the law of motion that the object follows when it is not stressed.

B, any object has inertia under any circumstances (i.e., no matter whether the object is stressed, balanced or unbalanced). When the object is unbalanced, inertia is manifested as "hindering" the change of motion state; The law of inertia is conditional.

☆ Sometimes people want to use inertia, and sometimes they want to prevent the harm caused by inertia. Please illustrate the above two points with examples (no need to explain). A: utilization: run-up of long jumpers; Hard work can throw stones far away; A few pedals will make the bike slide. Precautions: Passengers in the front row of minibus should wear seat belts; Keep a distance when the vehicle is driving; Packaging glass products should be padded with thick foam plastic.

Seven, two force balance

1. Definition: When an object is acted by two forces, it is said that the two forces are balanced if it can maintain a static state or a uniform linear motion.

2. Equilibrium conditions of two forces: two forces act on the same object with equal magnitude and opposite directions, and the two forces are in a straight line.

Summary: The conditions of the balance of the two forces can be summarized as "one, equality, opposition and one" in four words.

3. Comparison of balance force and interaction force:

Similarities: ① equal in size; ② The direction is opposite; 3 different points acting on a straight line: the balance force acting on an object can be different forces; The interaction forces acting on different objects are forces of the same nature.

4. The relationship between force and motion state:

The force of the object, the description of the motion state of the object.

Force is not the cause of exercise.

Under unbalanced force

The resultant force is not 0.

Force is the reason to change the motion state of an object.

5. Application: Using the two-force balance condition to solve the problem, you should draw a schematic diagram of the force on the object.

Pay attention when drawing: ① Draw gravity first, and then look at the contact between objects and those objects, you may be subjected to the force of these objects; (2) When drawing, we should also consider the motion state of the object.