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1. Celsius temperature regulations: When the atmospheric pressure is 1.01

Each equal part is called 1 degree Celsius and is represented by the symbol ℃. Relationship: T=t 273k, 1 k=1℃.

2． The tool for measuring temperature is a thermometer. The principle is based on the thermal expansion and contraction properties of liquids.

3. How to use a thermometer: Before measurement (1) observe the scale to select a suitable thermometer; (2) observe the graduation value for accurate reading. When measuring (1) the glass bulb of the thermometer is in full contact with the object to be measured; (2) the reading is taken after the indication is stable; (3) the glass bulb of the thermometer cannot leave the object being measured; (4) the line of sight is perpendicular to the scale of the thermometer.

4. Classification of thermometers:

Classification: Laboratory thermometer, thermometer, thermometer

Liquid contained: kerosene, mercury, alcohol, mercury

Measurement range -20℃～110℃ -20℃ ~50℃ 35℃~42℃

Graduation value 1℃ 0.1℃ 1℃

Structural features No shrinkage No shrinkage There is a very thin shrinkage

Readings cannot leave the object being measured. Cannot leave the object being measured. Can take readings away from the human body

Usage Notes None None Shake it before measuring

5. Crystal: A type of substance with a fixed melting temperature, such as sea wave, naphthalene, ice, salt, alum and various metals.

6． Amorphous: A type of substance that does not have a fixed melting temperature, such as beeswax, rosin, asphalt, glass, etc.

9． Changes in physical state: You can't type it out, you can find it in the book by yourself

Find it by yourself

Explanation:

(1) Crystal melting (solidification) characteristics: the temperature reaches Melting point (freezing point); continues to absorb (release) heat; temperature remains unchanged.

(2) There are two ways of vaporization: evaporation and boiling; two ways of liquefaction: lowering the temperature and compressing the volume.

Similarities and Differences Evaporation Boiling

Different

Same

Points Occurrence conditions At any temperature At a certain temperature (boiling point)

Location of occurrence Liquid surface Liquid surface and interior at the same time

Severity Slow Violent

Influencing factors Temperature, surface area of ??the liquid and speed of air flow on the liquid surface The temperature reaches the boiling point and continues to absorb heat , the temperature remains unchanged

Temperature changes, the own temperature decreases, the own temperature remains unchanged

The same point is that they are all vaporization phenomena, and they all absorb heat.

(3)

10. Liquefaction: rain, fog, dew, "white gas", small water droplets appearing on glass windows.

11. Condensation: Snow, frost, and ice flowers appear on glass windows.

12． Sublimation: camphor balls become smaller, frozen clothes become dry, sublimation of iodine, dry ice sublimation.

13． The inside of the refrigerator (evaporator) is vaporization, and the outside (condenser) is liquefaction.

14． Aerospace: Fuel: liquefying hydrogen to reduce volume and high calorific value; fairing: smooth to reduce friction, melting and vaporization occur.

1. Units of length: meters (m), kilometers (km), decimeters (dm), centimeters (cm), millimeters (mm), microns (?m), nanometers (nm).

Length unit relationship:

10 10 10

km m dm cm mm ?m nm

2. Tool for measuring length: scale. Commonly used ones include ruler, tape measure, tape measure, vernier caliper, and spiral micrometer (micrometer).

3. Method for measuring length with a scale:

Before measuring: (1) Select.

According to the measurement requirements, select a scale with appropriate range and graduation value.

(2) Recognize. Recognize the zero mark, range and graduation value of the scale.

When measuring: (1) Put. The scale is parallel to the object being measured, the scale line is close to the object being measured, and the zero mark is aligned with one end of the object being measured.

(2) Look. Look directly at the scale line, do not squint.

(3) Reading. When reading, estimate to the next digit of the graduation value.

(4) Note. Record measurements with exact values, estimates, and units.

4． Error: The difference between a measured value and the true value. Errors can only be reduced, not eliminated.

Reasons for errors: measurement tools are not accurate enough; measurement methods are not perfect enough; observations are not detailed enough.

Methods to reduce errors: use precise measurement tools; improve measurement methods; average multiple measurements.

5. Indirect length measurement methods: (1) Accumulation method; (2) Turning a curve into a straight method; (3) Coordination method.

6． Area unit:,.

Relationship between area units:

7. Volume units:,, liter (L), milliliter (mL). Tools for measuring liquid volume: graduated cylinder.

Relationship:

(L) (mL)

4. Mass units: ton (t), kilogram (kg), gram (g), milligram (mg). 1t=, 1mg=, 1g=.

Tools for measuring quality: balance (laboratory); scales, bench scales, steelyards and electronic scales.

How to measure mass with a balance: (1) Adjust the horizontal balance of the balance before use. Place the balance on a horizontal table, move the free scale to the zero position on the left side of the scale, and adjust the beam balance nut until the pointer points to the central scale line of the index plate. (2) When measuring: Place the object to be measured on the left pan of the balance, estimate the mass of the object to be measured, use tweezers to pick up the appropriate weight and place it on the right pan, and if necessary, move the balance to restore balance to the balance. The mass number of the weight in the right plate plus the scale value corresponding to the wandering code is the mass of the object to be measured.

The amount of matter contained in an object is called mass. Quality is a property of the object itself, independent of shape, state, temperature and position.

5. Density units: kilogram/m3 (kg/, gram/cm3 (g/). 1 g/=

The mass per unit volume of a certain substance is called the density of the substance. It is inherent to the substance A characteristic of.

Formula: Deformation formula: m=v, v=.

Density of water:, represents the mass of water per unit.

6． Methods for measuring the quality of solids and liquids;

7. Methods for measuring the density of solids and liquids;

8. New materials and applications;

1. Mechanical motion: the change of position of one object relative to another

2. Description of motion

Reference object: a standard object selected to describe whether an object is moving or stationary

Methods for judging whether an object is moving or stationary:

Moving and stationary Relativity: Choose different reference objects, and the description of motion may be different

3. Classification of motion

Uniform linear motion: motion along a straight line, the speed remains unchanged

Various speed linear motion: motion along a straight line, speed changes

Curved motion: motion along a curve

4. How to compare speed?

If the time is the same, the longer distance is faster

If the time is the same, the shorter time is faster

5. Speed

Physical meaning: Indicates how fast an object moves

Definition: The distance an object travels per unit time

Formula: v=s/t

Unit: m/s, km/h

Relationship: 1 m/s=3.6 km/h; 1 km/h=1/3.6m/s

6. Uniform linear motion

Definition: Movement along a straight line, the speed remains constant

Characteristics: The distance traveled in any time is the same

Formula: v=s/ t speed has nothing to do with changes in time and distance

7. Describe the speed of motion

Average speed

Definition: Describe the speed of an object moving at a variable speed within a certain distance (or (in a certain period of time)

Physical meaning: reflects the speed of an object during the entire movement

Formula: v=s/t

Instantaneous speed

Definition: The speed of a moving object at a certain moment

Physical meaning: Reflecting the movement of an object at a certain moment or position during motion

8 Measurement of average speed

Principle: v=s/t

Tools: scale, stopwatch

Physical quantities to be measured: distance s; time t

Note: Be sure to indicate which journey (or period of time)

Experiment report: title, purpose, equipment, steps, records, results

Sound Phenomenon

1. Sound is produced by the vibration of the sound-emitting body. Human speech relies on the vibration of the vocal cords to produce sound, string music relies on the vibration of strings to produce sound, wind instruments rely on the vibration of the air column in the tube to produce sound, cicadas rely on the vibration of the two eardrums on the chest, birds rely on the vibration of the song membrane, crickets, bees, mosquitoes , Flies make sounds by vibrating their wings.

2． All objects that produce sound are vibrating. When the vibration stops, the sound production also stops. The object that makes the sound is called the sound source.

1. Sound relies on the medium and propagates in the form of sound waves. The general propagation speed in the medium is: solid gt; liquid gt; gas.

2． The conditions for people to hear sound: (1) There is a sound source; (2) There is a medium; (3) There are good ears.

3. Sound waves propagate into the ear canal, causing the tympanic membrane to vibrate, and then pass through other tissues to stimulate the auditory nerve. This signal is transmitted to the brain, resulting in hearing.

3. The propagation speed of sound in air at room temperature is 340m/s.

4. The shortest time interval for the human ear to distinguish original sound from echo is 0.1s, and the shortest distance is 17m. Echo ranging formula: S=1/2vt.

1. Musical sound refers to the sound produced by regular vibrations of objects.

2． The three characteristics of musical sound are: pitch, loudness and timbre.

3. Pitch refers to the pitch of a sound. Pitch is related to the frequency at which the sounding body vibrates. The higher the frequency, the higher the pitch. Frequency refers to the number of times an object vibrates within 1 second, reflecting how fast the object vibrates. The frequency range of sound that most people can hear is 20Hz-2000Hz.

4． Loudness refers to the strength of a sound. Loudness is related to the amplitude of the sound emitter. The greater the amplitude, the louder the loudness. It is also related to the distance from the person to the sound emitter. The further the distance, the weaker the sound heard.

5. Timbre, also called timbre, refers to the quality of the sound. It has to do with the sound emitter itself.

1. From a physical perspective, noise refers to the sound produced by the irregular vibration of the sound-emitting body. From the perspective of environmental protection, all sounds that affect people's normal rest, study and work, as well as sounds that interfere with the sounds people want to listen to, are noises.

2． The level of noise intensity is expressed by sound level, the unit is decibel, and the symbol is: dB. Set the sound that people can just hear as 0dB, 15dB-40dB is a better living environment, and if it exceeds 70dB, it will be unbearable for a long time.

3. There are three ways to attenuate noise: (1) Attenuate the noise where it originates (2) Isolate and absorb sound waves along the transmission path (3) Prevent the noise from entering the ear.

1. Sound waves with a frequency higher than 20,000 Hz are called ultrasonic waves.

2． Utilization of ultrasonic waves: (1) Echolocation; (2) Sonar; (3) B-ultrasound; (4) Industrial ultrasonic flaw detector; (5) Ultrasonic cleaning; (6) Ultrasonic waves crush gallstones.

Light phenomena

1. A luminous object is called a light source. Stars, lightning, glowing incandescent lamps, glowing neon lights, light-emitting diodes, fireflies, candlelight fish are sources of light; the moon is not a source of light. Light sources are divided into natural light sources and artificial light sources.

2． Light propagates along straight lines in a homogeneous transparent substance.

3. Shadows, solar eclipses, lunar eclipses, pinhole imaging, laser collimation, standing in a straight line, "three points and one line" when shooting, and carpenters testing whether the wood surface is smooth are all linear propagation of light.

4． The speed of light in vacuum is about 3, in water it is 3?4 in air, in glass it is 2?3 in air

5. When light is reflected, the reflected light, the incident light and the normal are in the same plane; the reflected light and the incident light are located on both sides of the normal; the reflection angle is equal to the incident angle. When light is reflected, the optical path is reversible. Both specular reflection and diffuse reflection follow the laws of light reflection.

6． Applications of plane mirrors: ① Change the optical path ② Imaging.

7. The principle of plane mirror imaging: the law of reflection of light. (Essence: It is the intersection point of the reverse extension line of the reflected light)

8. The characteristics of plane mirror imaging: ① form an upright virtual image ② the size of the image and the object are equal ③ the distance between the image and the object to the mirror is equal ④ the line connecting the object and image is perpendicular to the mirror ⑤ the image is consistent with the top and bottom of the object, and the left and right are reversed.

9. Convex mirrors have a divergent effect on light, and the rearview mirror of a car is a convex mirror.

10. Concave mirrors have a converging effect on light. Solar cookers, large reflecting telescopes, and car headlights are concave mirrors.

11. When light is refracted, the refracted ray, the incident ray and the normal are in the same plane; the refracted ray and the incident ray are located on both sides of the normal respectively; when light enters water or glass obliquely from the air, the refraction angle is smaller than the incident angle; the light passes from water Or when the glass is incident into the air obliquely, the refraction angle is greater than the incident angle; when the incident angle increases (or decreases), the refraction angle also increases (or decreases). When light is refracted, the optical path is reversible.

12． The dispersion phenomenon shows that white light is not monochromatic light, but is composed of red, orange, yellow, green, blue, indigo, violet and other colored lights.

13. The three primary colors of light: red, green, and blue. The three primary colors of pigments: red, yellow, and blue.