1. Why does sorbet get angry?
The reason why sorbet bubbles is because there is a lot of invisible water vapor in the outside air. When it comes to cold sorbet, it will liquefy into droplets when it is cold. It seems that the sorbet is bubbling.
2. Why do sunflowers always face the sun?
Sunflower stems contain a wonderful auxin. This auxin is very afraid of light. When it is illuminated, it will go to the backlight side, and the cells on the backlight side will multiply rapidly. Therefore, the backlit side will grow faster than the bright side, which will bend the sunflower to light.
3. Why do cicadas shed their skin?
Cicada's shell (exoskeleton) is hard and can't expand with the growth of cicada. When the cicada grows to a certain stage, the cicada's exoskeleton restricts its growth, and the cicada loses its original exoskeleton, which is cicada slough.
4. How do bees make honey?
Bees spit the collected sweet flower juice into an empty beehive. At night, they suck sweet juice into their honey stomachs to make it, and then spit it out and swallow it. It takes 65,438+000 ~ 240 times to make sweet honey.
5, hanging on the wall of the quartz clock, when the battery runs out and stops, its second hand often stops at the "9" position on the dial. This is because the second hand is most hindered by the large torque at the "9" position. Scientific common sense
6. 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.
7. When taking pictures on TV, turn off the camera flash and indoor lighting to make the picture 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.
8. At the same temperature, frozen meat 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,
2. Little scientific knowledge in life
Pendulum synchronization principle
Fuse-excessive current causes heat to increase and the fuse is burned.
Air valve on the pressure cooker-To avoid excessive pressure in the cooker, please open the lid.
Steaming steamed bread with soda ash and Na2CO3, heating to produce CO2, making steamed bread "fat".
The tip of the lightning rod discharges, guiding the current from the clouds to a lower place to prevent it from hitting the building.
When cooking in an iron pan, iron can be dissolved in the dish to supplement the iron needed by the human body.
Sprinkling water on the ground in summer will be cooler because of evaporation and cooling.
To make the hammer tighter, you can hit it with the handle of the hammer, which is based on inertia.
The purpose of thermometer is to use liquid to expand when heated and contract when cooled.
When you hit someone hard, you will feel pain, too, because the action of force is mutual.
3. What are the scientific tips in life?
Common sense of life science-avoid cooking with cold tap water. Many people are used to cooking with cold tap water, which is actually unscientific.
Because raw and cold tap water contains a certain amount of chlorine, it will destroy the indispensable vitamin B 1 in the cooking process. According to the determination, the loss of vitamin B 1 when cooking with tap water is directly proportional to cooking time and temperature. Generally speaking, the loss is around 30%.
If you cook with boiled water, vitamin B 1 can be saved from loss, because boiled water and chlorine have evaporated with water vapor. Don't squeeze water when making dumpling stuffing. In daily life, people often use Chinese cabbage, leek, celery, pig, mutton, etc. as dumpling stuffing.
Because there is more water in vegetables, people are used to squeezing out the water in the stuffing to prevent the soup from flowing. This practice is unscientific.
Because vegetable water contains a lot of B vitamins and vitamin C, it also contains carotene and minerals needed by human body. And after squeezing out the soup, the wrapped jiaozi tastes very dry.
So, how can we not squeeze out the water in the stuffing and prevent the stuffing in jiaozi from flowing? The method is as follows: firstly, chop the meat and onion, add seasoning and mix well, then chop the Chinese cabbage without adding salt, and add the chopped Chinese cabbage into the meat stuffing bit by bit, while stirring, so that the meat stuffing can absorb the water in the vegetable stuffing evenly, and the packaged jiaozi tastes delicious. Don't eat hot food. Some people like to eat very spicy food. This habit is very harmful.
After investigation, the incidence of esophageal cancer is related to eating hot food and hot food. The normal temperature of human mouth and esophagus is 36.5~37.2℃, and the heat-resistant temperature is 50~60℃.
If the temperature of eating and drinking water is too high, it will burn the oral mucosa and esophageal wall. People feel very hot and very hot food, usually at 70~80℃. If they eat this kind of food regularly, the mucosa of the oral cavity and esophageal wall will be damaged continuously, and new cells will continue to proliferate.
If long-term pathological changes and inflammation accelerate the process of cell regeneration, it is likely to become oral cancer and esophageal cancer. Therefore, it is not advisable to eat hot food.
Avoid using painted chopsticks. Drawing chopsticks is beautiful and cheap, but from a health point of view, it is harmful to health. This is because.
Paint is a polymer organic compound, which mostly contains toxic chemical components, especially yellow paint. Made of yellow pigment containing lead and chromium, the lead content accounts for 64% of the total pigment, and the chromium content reaches 16. 1%. Some green (blue and yellow mixed) and brown (yellow, red and black mixed) paints also contain lead and chromium.
Eating with painted chopsticks for a long time, especially when the paint falls off and is swallowed with food, lead, chromium and other toxic substances will enter the human body and accumulate, leading to chronic poisoning. The lead poisoning dose is 0.04g, and the lethal dose is about 20g.
When the amount of lead entering the body per mouth exceeds 1 mg, it will cause harm to the human body. Lead mainly damages the nervous system, hematopoietic organs and kidneys. In severe cases, it can lead to oral metal ignorance, lead in gums, gastrointestinal symptoms, neurasthenia and muscle pain.
In particular, it will affect children's intellectual development. Therefore, in daily life, it is best not to eat with painted chopsticks, but to choose high-quality bamboo chopsticks or non-toxic wooden or plastic chopsticks that meet hygiene standards.
4.50 Scientific knowledge in life
1. When taking medicine, don't use tea to deliver medicine, because tea will neutralize the medicine and reduce its medicinal properties.
2。 It is harmful to drink tea when you have a fever, because theophylline contained in tea will raise the temperature of human body, affect and reduce the effect of drugs, thus aggravating the condition. Therefore, it is not advisable to drink tea when you have a fever.
3。 Wearing red clothes can absorb and filter out more ultraviolet rays from the sun, thus reducing the harm of ultraviolet rays to the skin.
4。 Children should not eat sugar on an empty stomach, because it will affect normal metabolic function.
5。 Putting fresh eggs in limewater can keep them fresh, because the carbon dioxide exhaled by eggs reacts with limewater to generate calcium carbonate, which blocks the micropores on the surface of eggs and prevents oxidation and deterioration.
6。 In order to prevent food from being affected with moisture, deterioration or deformation, food bags are often filled with gas carbon dioxide or nitrogen; Or put desiccant in the bag: quicklime and calcium chloride mainly absorb water, and iron mainly absorbs oxygen and water; Or vacuum package.
7。 The gases in swim bladder are mainly carbon dioxide and oxygen.
8。 It's important to add some soda when making steamed bread. In order to neutralize the acid produced during flour fermentation, the carbon dioxide produced can make bread loose and porous.
9。 The residual pesticides in vegetables can be soaked in alkaline substances, which can reduce the medicinal properties of pesticides.
10。 Adding vinegar can remove the astringency of preserved eggs.
1 1。 The odor of refrigerator can be removed by activated carbon, that is, the adsorption of activated carbon is used.
12。 The scale on aluminum pot (mainly calcium carbonate and magnesium hydroxide) can be removed by hydrochloric acid or vinegar.
1, quartz clock hanging on the wall, when the battery runs out and stops, 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 meat 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,
5. When the pot is filled with cold water, the water droplets attached to the outer surface of the pot bottom can only dry out after a long time on the flame, and only when they are dry will they 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.
5.50 Scientific knowledge in life
1. When taking medicine, don't use tea to deliver medicine, because tea will neutralize the medicine and reduce its medicinal properties.
2。 It is harmful to drink tea when you have a fever, because theophylline contained in tea will raise the temperature of human body, affect and reduce the effect of drugs, thus aggravating the condition. Therefore, it is not advisable to drink tea when you have a fever.
3。 Wearing red clothes can absorb and filter out more ultraviolet rays from the sun, thus reducing the harm of ultraviolet rays to the skin.
4。 Children should not eat sugar on an empty stomach, because it will affect normal metabolic function.
5。 Putting fresh eggs in limewater can keep them fresh, because the carbon dioxide exhaled by eggs reacts with limewater to generate calcium carbonate, which blocks the micropores on the surface of eggs and prevents oxidation and deterioration.
6。 In order to prevent food from being affected with moisture, deterioration or deformation, food bags are often filled with gas carbon dioxide or nitrogen; Or put desiccant in the bag: quicklime and calcium chloride mainly absorb water, and iron mainly absorbs oxygen and water; Or vacuum package.
7。 The gases in swim bladder are mainly carbon dioxide and oxygen.
8。 It's important to add some soda when making steamed bread. In order to neutralize the acid produced during flour fermentation, the carbon dioxide produced can make bread loose and porous.
9。 The residual pesticides in vegetables can be soaked in alkaline substances, which can reduce the medicinal properties of pesticides.
10。 Adding vinegar can remove the astringency of preserved eggs.
1 1。 The odor of refrigerator can be removed by activated carbon, that is, the adsorption of activated carbon is used.
12。 The scale on aluminum pot (mainly calcium carbonate and magnesium hydroxide) can be removed by hydrochloric acid or vinegar.
6. Popular science knowledge is in life.
Small knowledge of science and technology
Plug tip
Why do electric fans, washing machines, refrigerators and other household appliances mostly use three-wire plugs? What is the difference between a three-wire plug and a three-phase plug?
Three-phase electrical appliances refer to three different live wires, and the voltage between each two wires is 380 volts. They are generally used in power systems and are more common in industrial electricity consumption. Single-phase power supply is generally used in household appliances, and its three wires are live wire, neutral wire and ground wire. The voltage between the live wire and the neutral wire is 220 volts, so this is not three-phase electricity, and its plug socket is not a three-phase plug socket. The grounding wire is to ensure safety.
Fruit with antihypertensive effect
Hawthorn; Hawthorn can dilate blood vessels and lower blood pressure and cholesterol. You can choose 10 wild hawthorn (fresh is better), mash it with 30 grams of white sugar, and take it after decocting in water, which has a good effect of lowering blood pressure and invigorating stomach.
Bananas; Bananas contain a variety of vitamins, which can clear away heat and lower blood pressure and can be eaten regularly. It is also effective to decoct with 30~60 grams of banana peel or fruit stalk. Take a proper amount of plantain flowers and take them with water, and the curative effect is better.
Water chestnut; It has the effect of clearing away heat and lowering blood pressure. You can use fresh water chestnut (washed, mud removed) and jellyfish (washed and salt removed) to cook soup three times a day. It can not only lower blood pressure, but also reduce phlegm and relieve cough.
Pineapple basket: Eating pineapple regularly can strengthen the hydrolysis of fibrin in the body, which has a good effect on improving blood circulation and eliminating edema and inflammation in hypertension, edema and thrombosis.
Mume: Rich in citric acid, malic acid and succinic acid. For those with hypertension, dizziness, insomnia and difficulty sleeping at night, 3 pieces of ebony and appropriate amount of rock sugar can be stewed with boiling water, which has the functions of lowering blood pressure, sleeping peacefully, clearing away heat and promoting fluid production.
Apple: contains malic acid, citric acid, vitamins A, B, C and other nutrients 10. Eating apples often can improve arteriosclerosis.
Five secrets of drinking milk scientifically
Drinking milk is good for health, but many people still have some conceptual misunderstandings about drinking milk. This article introduces some common sense of drinking milk scientifically.
1. It is not advisable to drink milk on an empty stomach in the morning. Because the gastrointestinal peristalsis is fast when the human body is on an empty stomach, the nutrients in milk often rush into the large intestine before being absorbed. In addition, the method of swallowing milk is not feasible, because it will reduce the chance of mixing with saliva in the mouth, which is not conducive to digestion and absorption. You'd better eat some biscuits, cakes, etc. Before drinking milk, or eating snacks while drinking milk.
Drinking milk at night is more beneficial. Scientific research has found that there is a special law of calcium metabolism in human body: at night, especially at midnight, the plasma calcium content will appear a "trough", forcing the body to transport part of calcium in bones to supplement it through regulation mechanism. Although this temporarily maintains the calcium in the blood, the calcium in the bones is reduced. Milk is rich in calcium. Drinking a glass of milk before going to bed can compensate the body's demand for calcium at night.
7. Scientific tips in life. Thank you.
Magical use of vinegar
1. Vinegar is an essential condiment for home cooking. Add two drops of white wine and a little salt to vinegar to make fragrant vinegar. exist
When cooking meat or potatoes, adding a small amount of vinegar will make it easy to stew and taste good. Adding vinegar when cooking sweet porridge can make sweet porridge sweeter.
2. When polishing shoes, a drop of vinegar can make shoes shine for a long time: use copper and aluminum utensils and then clean them with vinegar.
Can restore luster; 20 minutes before killing chickens and ducks, pour a spoonful of vinegar on the chickens and ducks, and pluck the hair easily.
3. The paint on the glass is softened with vinegar and wiped off; After washing the silk, soak it in clear water and a little vinegar.
Soak for a few minutes, dry and polish.
8. 50 little scientific knowledge around you
Why do the stars twinkle?
We see the stars shining, not because the luminosity of the stars has changed, but because of the occlusion of the atmosphere.
The atmosphere is between us and the stars. When starlight passes through the atmosphere, it will be affected by the density and thickness of the atmosphere. The atmosphere is not absolutely transparent, and its transparency will change according to its density. So when we look at the stars through it on the ground, we will see that the stars seem to be flashing.
2. Why do people yawn?
When we feel tired, a lot of carbon dioxide has been produced in our bodies. When there is too much carbon dioxide, oxygen must be supplemented to balance the needs of the body. Because these residual carbon dioxide will affect our body's functional activities, then the body will send out a protective reaction, so we yawn.
Yawning is a deep breathing action, which will let us breathe in more oxygen and expel more carbon dioxide than usual, and it can also eliminate fatigue.
3. Why can snakes walk without feet?
Snakes have many scales, which are the outermost armor on their bodies. Scales are not only used to protect the body, but also to be their "feet".
When a snake crawls forward, its body will be S-shaped. Every scale outside the S-shape will tilt upward to help the snake catch the uneven road when it moves forward. These scales cooperate with the snake's muscles and can push the body forward, so the snake can walk without feet!
4. Why do sunflowers always bloom towards the sun?
There is a substance called "auxin" in the stem under the sunflower disk. This substance has the function of accelerating replication, but it is anti-optical, and it will run to the backlight side whenever it encounters light.
So when the sun rises, the stem of the sunflower immediately hides to the side of the backlight, as if the whole plant is bent in the direction of the sun.
5. Why does hair turn white when people are old?
There is a substance called melanin in our hair. The more melanin, the darker our hair will be. Without melanin, hair will turn yellow or white. When human beings reach old age, various functions of the body will gradually decline, and the formation of pigments will be less and less, so the hair will gradually turn white!
6. Why do fireflies glow?
Fireflies emit light because there is a luminous body at the end of their abdomen, which is filled with a lot of phosphorus-containing luminescent substances and luminescent enzymes, so that fireflies can emit flashing light.
The purpose of fireflies is not only lighting, but also courtship, vigilance and trapping. This is also a communication tool for them. Different kinds of fireflies emit light in different ways, frequencies and colors, so they can convey different information.
7. Why do you growl when you are hungry?
When you are hungry, you will purr. This is because the food you have eaten before has almost been digested. Although the stomach is empty, the gastric juice in the stomach will continue to secrete. At this time, the contraction of the stomach will gradually expand, and the liquid and gas inside will be stirred up and purr.
Don't be embarrassed by your stomach growling next time.