The way of nature in life

When the quartz clock hanging on the wall stops moving when the battery is exhausted, its second hand often stops at the position of "9" on the dial. This is because the second hand is most hindered by the large torque at the "9" position.

2. Sometimes, when tap water flows from the adjacent faucet, it occasionally makes bursts of noise. This is because the water pipe vibrates when the water rushes out of the tap.

3. When taking pictures in front of the TV screen, turn off the camera flash and indoor lighting to make the pictures clearer. Because the reflected light of the flash lamp and the illuminating lamp on the TV screen will interfere with the transmitted light of the TV picture.

At the same temperature, frozen pork thaws faster in water than in air. At the same temperature, hot nails cool faster in water than in air. A cup filled with boiling water cools faster when immersed in water than when immersed in air at the same temperature. All these phenomena show that water has better heat transfer performance than air,

When the pot is filled with cold water, the water droplets attached to the outer surface of the pot bottom can only be dried on the flame for a long time, and then they will boil. This is because the water droplets, the pot and the water in the pot keep heat conduction, and the temperature is similar. As long as the water in the pot is not boiled, the water droplets will not boil, but will evaporate on the flame and gradually dry up.

6. Distorted mirror, the farther people are from the mirror, the more distorted they are. Because the image in the mirror is formed by the reflection of the silver-plated surface behind the mirror, uneven silver-plated surface or uneven glass thickness will lead to aliasing. The farther away from the deformed mirror, the more the reflected light on the silver-plated surface deviates from the normal position according to the principle of light amplification, and the more deformed the mirror is.

7. There are several small holes communicating with the outside world on the side of the gas nozzle of the natural gas furnace, but natural gas will not be ejected from the side holes, but only from the nozzle. This is because the air velocity at the nozzle is high, and according to the principle of fluid mechanics, the air surface pressure is lower than the atmospheric pressure outside the side hole, so the natural gas will not be ejected from the side hole of the nozzle.

8. After blowing the balloon, hold the mouthpiece with your hand and then suddenly release it. The air in the balloon is ejected and the balloon moves due to recoil. You can see that the route of balloon movement is tortuous. There are two reasons: first, the thickness and tension of the inflated balloon are uneven everywhere, which makes the balloon contract unevenly and swing around when it is deflated, thus the movement direction changes constantly; Second, the shape of the balloon is constantly changing during the contraction, so the air velocity on the surface of the balloon is also constantly changing during the movement. According to the principle of fluid mechanics, the air pressure on the surface of the balloon is constantly changing, so the balloon swings and the direction of movement is also constantly changing.

9. When the ceiling fan rotates normally, the tension at the suspension point is smaller than when it does not rotate. The greater the rotational speed, the more the tension decreases. This is because when the ceiling fan rotates, the air has an upward reaction force on the ceiling fan blades. The greater the speed, the greater the reaction.

10, electric furnace "combustion" is the conversion of electric energy into internal energy. Without oxygen, it can only oxidize electric furnace wires, shortening service life.

1 1. Even if there is no wind, the path of paper dropping is tortuous. This is because each part of the paper has different convexity and concavity and shape, so in the process of falling, the air speed on its surface is different. According to the principle of fluid mechanics, there is uneven air force everywhere on the paper, which changes with the movement of the paper, so the paper keeps rolling and falling zigzag.

On a clear day, according to the sunrise and sunset, you can easily know the east and the west, and you can judge the profile, but it can only be a rough estimate. There are the following methods to determine more accurately:

1, watch direction finding "hours are half of the sun, 12 refers to the north". Generally, you can quickly identify the direction between 9: 00 am and 4: 00 pm, and the direction you point to half the time is facing the sun, and 12 is the north. For example, in the afternoon 14:40, half is 7: 00. Or put a watch, put a stick in the center of the watch to turn the watch, so that the shadow of the stick coincides with the hour hand, and the bisector between the hour hand and 12 is north.

It must be noted that (1) when judging the direction, the watch should be flat; (2) In the area between 20 30' south latitude, it is not suitable for use around noon, that is, every 15 plus 1 hour in the east and every 15 plus 1 hour in the west. The direction of the sun shadow is sunny, and a wooden stick is erected on the ground. The shadow of the stick moves with the position of the sun. These shadows are the shortest at noon, the connecting line at the end is a straight line, and the vertical line of the straight line is the north-south direction. Draw a series of concentric circles on a piece of 50×50cm drawing paper, with the radius of concentric circles increasing by 1cm, nail them horizontally on a flat plate, and vertically insert a thin steel needle or needle with a length of 12- 15cm on the center of the circle. When the position of the sun changes, the endpoint of the shadow always intersects with the concentric circles. Draw these points, then connect two straight lines on the same circle, and connect the midpoint of these straight lines with the center of the circle. This connecting line is the north-south direction line, and the direction of the arc top is the north.

Night star

At night, you can judge the direction according to Polaris and Southern Cross.

1, Polaris: Polaris is located in the northern sky, and its exposed altitude angle is equivalent to the local latitude, so it can be found quickly. Usually according to the Big Dipper (Ursa Major) or the W Star (Fairy Queen). The Big Dipper is seven bright stars, shaped like a spoon. The place where the two β -α directions of the spoon extend about 5 times is Polaris. When you can't see the Big Dipper, you can look for the North Star according to the constellation W after Fairy. Cassiopeia consists of five bright stars, shaped like a "W" letter, and the distance between the opening direction and the opening width of the letter is about twice that of Polaris.

2. Southern Cross: In the area south of 23 30' north latitude, the Southern Cross is sometimes seen at night. It consists of four bright stars in the shape of a "cross", and at the lower right, four and a half times (no stars) of the connecting line between the two stars from γ to α is due south.

Ground features and plant features

Sometimes some ground objects and plant growth characteristics in the wild are good direction signs. Increasing this knowledge can help you quickly identify the direction.

1, function:

A. House: Generally, the door faces south, especially in the north of China;

B. temples: usually open to the south, especially the main buildings in the temple group;

C. distinctive features: bryophytes, the base of which is moist to the north, may grow low.

2, plant growth characteristics:

A generally, on the shady slope, that is, the northern slope, low ferns and lianas are more developed than on the sunny slope.

B. The branches and leaves of a plant flourish on the sunny side, and moss may grow on the shady trunk in the north.

C clear annual rings can be seen on the trunk sections of many trees in northern China, with sparse annual rings on the south side and dense annual rings on the north side.