2, the mirror is full of water
the reflection of light, the plane mirror becomes a virtual image.
3, a mirage
light refraction.
4. A rising tide lifts a boat.
Relative stillness, relativity between motion and stillness, buoyancy, and conditions for objects to float.
5, the leaves fall back to the roots
gravity, the direction of gravity is vertical downward, and the potential energy of gravity is converted into kinetic energy.
6, it is difficult to sound with one hand
Force is the action of objects on objects, which vibrates and sounds.
7, if you are on pins and needles
The stress area is small and the pressure is strong.
8. The generation and spread of the false alarm will weaken the sound in human ears.
9, penetrating
diffusion, molecular thermal motion.
1, anger rushing to the crown
Together, force can change the motion state of an object.
Proverbs
12. A straight body is not afraid of crooked shadows.
straight-line propagation of light
13. The drum must be hammered again.
increase the amplitude and make it louder
14. Real gold is not afraid of fire.
the melting point of gold is 15%, which makes it easy to enjoy the cool under the big tree, and the flowers in the wall are fragrant outside the wall.
diffusion, molecular thermal movement
16. It is late to rein in the cliff immediately, and it is late for the ship to fill the leak in the middle of the river. Inertia, buoyancy
17. Sharpening the knife does not mistake the woodcutter.
reduce the stress area, increase the pressure, and improve the efficiency
18.
Force can change the motion state and shape of an object
19. Although the weight is small, it weighs a thousand pounds.
lever principle
2. People go higher and water flows lower.
the potential energy of gravity increases, and it overcomes gravity to do work, and the potential energy is converted into kinetic energy
Third, two-part allegorical sayings
21. The flute is played in the suona, and the sound (thought) is different.
timbre of sound
22. Toad sits at the bottom of the well and only sees the sky with a big bowl.
Straight-line propagation of light
23. The monkey fished for the moon with a sieve.
The reflection of light makes the plane mirror into a virtual image
24. Drinking hot tea with glasses makes you more hazy.
Liquefaction of water vapor, diffuse reflection of light
25. When a stone touches a stone, it will get angry.
path, magnetic effect of current, conversion of electric energy into mechanical energy, generation and propagation of sound
26. Elephant's ass can't be pushed.
Great mass and great inertia
27. Woodpeckers make holes only with their mouths shut.
by reducing the stress area and increasing the pressure, the force can change the shape of the object
28. The inflated ball will jump up.
mutual transformation of mechanical energy
29. Wear nail shoes and crutches, and be steady and steady.
Increase friction and balance force
3. Hold down the bell and don't raise your hand. It always rings.
the forces between objects are interactive, and mechanical energy is converted into internal energy.