1. For example, water should be boiled to 100 degree.

2. The straw is curved to the touch in water, which is the refraction of water.

Foods in canned food are not easy to go bad. They can be stored for a long time without going bad. This is because the can is sealed, so bacteria can't enter.

Sunflowers always bloom towards the sun, and 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.

Science, which means learning by subject, later refers to gradually forming a complete knowledge system through careful classification (such as mathematics, physics, chemistry, etc.). ). It is the knowledge about the practice of discovery, invention and creation, and it is the general name of the knowledge system for human beings to explore, study and understand the changing laws of everything in the universe.

2. Little scientific knowledge in life

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! Because this is a normal physiological action.

8. Why can't ostriches fly? A giant ostrich, but they can't fly into the sky! This is not because their wings are useless, but because their feathers are too soft and their wings are too small to fly at all. In addition, the ostrich's muscles are underdeveloped and its sternum is flat, which is not conducive to flying.

Ostriches live in Africa. Because they have lived in desert areas for a long time, their bodies gradually evolved into what they are now in order to adapt to the environment. 9. Why can't it go bad easily? Lunch meat, black bean shad, tomato sauce beans.

They are all delicious canned food, which can be preserved for a long time without deterioration.

This is because the can is sealed, so bacteria can't enter. When people make canned food, they pump all the air out of the canned food and then seal it.

In the absence of air, even if the food inside is contaminated with a little bacteria, they can't survive or reproduce! 10. Why does the baby cry all the time when it is born? Babies cry when they are born, not because they are unhappy, but because they are taking the first breath of air! When babies leave their mother's body and are born, the first breath of air will rush to their throats, violently impact the vocal cords, make them vibrate, and then make a sound similar to crying. 1 1. Why do lizards keep bouncing up after their tails are broken? In order to protect themselves, many lizards also protect their eyes and ears; When some lizards are attacked, their tails will be broken due to the severe contraction of their muscles.

Because there are still some nerves alive in the broken tail, it will keep bouncing, thus distracting the enemy and running away. Don't think that their lives will end like this. In fact, it only takes a few months, and their tails will grow back and continue to live.

12. Why is the squirrel's tail so big? Don't look at the relaxed mouse tail! When the squirrel jumps around the tree, its tail plays a great role. It can keep balance when the squirrel jumps to the tree to avoid falling and being injured.

In addition, this big tail can play a more protective role in winter, tightly surrounding the squirrel's body, which is convenient and practical. 13. Why can't a person have one or three thumbs? The average person has five fingers, each with a different length.

However, does anyone realize that besides the thumb, other fingers also have three sections, while the thumb alone has only two sections? It turns out that the number of joints is just the same as the other four fingers. If it is three knots, the thumb will appear weak, so that it can't lift heavy objects; If there is only one section, it can't grasp things freely with the other four fingers! 14. Why don't you scratch yourself? When others scratch ourselves, we feel itchy and laugh nonstop; However, when we scratch ourselves, we not only don't laugh, but also don't itch.

Based on our psychological preparation, the brain will send out a message that there is no danger, and the nerves will relax, so that they will not laugh and itch! 15. Why are most seawater blue and green? Looking at the sea, it is often found that the sea water is blue-green. However, when you pick up the sea water, you can only see it as transparent and colorless as old water.

It turns out that the seawater itself is not as big as the water we touch every day.

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, leeks, celery, pigs and mutton to make jiaozi. Because vegetables contain a lot of water, people are used to squeezing the water out of jiaozi 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 hot food. This habit is very harmful. 323 13 133532363 1343 1333 13635333 EB 893 e5b 13333332638。 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 that food is very hot, 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 not good for your 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. Life science tips

1. If you eat spicy food and think it will kill you, just put a little salt in your mouth, hold it, spit it out and rinse your mouth, so it won't be spicy; ? 2. Yellow teeth, you can chew peanuts in your mouth and brush your teeth for three minutes, which is very effective; 3. If there is a small area of skin damage or burns, immediately apply a little toothpaste to stop bleeding and relieve pain; ? 4. Always leave ugly tea stains in the cup filled with tea, and wash it with toothpaste, which is very clean; ? 5. Open your mouth slightly when you look up at the eye drops, so that your eyes will not blink; ? 6. If there is an ulcer in the mouth, stick it on the ulcer with vitamin C, and it will basically be fine after the ulcer dissolves; ? 7. Small dust enters your eyes, close your eyes and cough a few times, and the dust will come out by itself; ? 8. After washing your face, gently apply some fine salt on both sides of your nose with your fingers, and then rinse with water, so that blackheads and acne will be removed and pores will become smaller; ? 9. When you have just been bitten by a mosquito, it doesn't itch when you apply soap; ? 10. If the throat and gums are inflamed, cut the watermelon into small pieces at night and eat with salt. Remember that it must be at night, when the symptoms will be relieved and the next day will be fine; ? 1 1. The hair dryer blows at the label, and when the glue of the trademark is hot, the label is easily torn off; ? 12. If you are afraid of wrinkling when traveling with clothes, you can roll up everything; ? 13. Drinking vinegar when burping will get immediate results; ? 14. Eat something that smells bad, such as garlic and stinky tofu, just eat a few peanuts; ? 15. Treat cough, especially dry cough. Before going to bed at night, fry eggs with pure sesame oil, add a little more oil, and don't put any seasoning. Sleeping in hot weather and eating for several days have obvious effects; ? 16. MM with long and thick wrists cannot wear thin bracelets. You should put a plastic bag on your hand and wear a bracelet. It's very easy to wear and won't hurt your hands. Take it off in the same way; ? 17. Chestnut skin is difficult to peel. Peel off the shell first, then turn it in the microwave oven, take it out while it is hot and rub it, and the skin will fall off; ? 18. When arranging flowers, drop a drop of detergent in the water for several days; ? 19. Steam walnuts in a pot for 10 minutes, then take them out and break them in cold water to take out the complete peach kernels; ? 20. Put the shrimps in a bowl, add a little salt and edible alkali powder, rub them with your hands for a while, then soak them in clear water, and then rinse them with clear water, which will make the fried shrimps transparent as crystal, refreshing and delicious; ? 2 1. When frying meat, first soak the meat in baking soda water for more than ten minutes, then pour out the water and try it again. It will be tender and smooth when fried; ? 22. Soaking the remaining tea leaves in water for a few days and then pouring them on the roots of plants can promote the growth of plants; ? 23. Dry the remaining tea leaves and smoke them in the toilet or ditch, which can eliminate the stench and drive away mosquitoes and flies; ? 24. uncooked rice re-cooking method: you can use chopsticks to tie some holes in the rice that go straight to the bottom of the pot, sprinkle a little yellow wine and stew it again. 25. If it's just a noodle clip, turn the noodles to the middle and simmer; ? 26. Clever removal of greasy screen windows: Put the cigarette butts left after washing clothes and smoking in water, and use them to clean glass windows and screens after dissolution. The effect is really good; ? 27. As long as you put a small piece of chalk in the jewelry box, you can keep the jewelry shiny; ? 28. Self-adhesive traces on the surface of tables and bottles can be wiped with wind oil essence; ? 29. Always carry a small dry battery in your bag when you go out. If the skirt is charged with static electricity, wipe the battery positive electrode on the skirt several times to remove static electricity; ? 30. No matter where your shoes rub your feet, you should apply a little white wine to the place where your shoes rub your feet to ensure that you don't rub your feet. ? 3 1. When mixing vegetables, if you have to blanch, you'd better make full use of the water for blanching good dishes.

If you cook jiaozi, you can put a proper amount of water in the meat stuffing, which not only ensures the nutrition, but also makes the dumpling stuffing delicious and fragrant. ? 32. In summer, feet are prone to sweating. Soaking feet with light salt water every day can effectively deal with sweaty feet; ? 33. Sunbathing after swimming in summer can prevent diseases such as skin strain; ? 34. In summer, pillows are prone to damp and mildew, and frequent contact with pillow cores is good for health; ? 35. Eat more wet spleen such as glutinous rice porridge, which can prevent heatstroke and damp; ? 36. Anti-insomnia: Talk less before going to bed, avoid drinking strong tea, don't use your brain before going to bed, and wash your feet with hot water and vinegar; ? 37. Honeysuckle has the effect of dispelling wind and dampness. Honeysuckle can be mixed with honey to relieve summer heat after being decocted in water to cool the juice; ? 38. Drinking tea after eating too greasy food can discipline nerves and promote fat metabolism; ? 39. Lack of sleep will make you stupid. You need to sleep for eight hours every day. Having a nap habit can delay aging. ? 40. Hands tend to become dry and rough. Soaking your hands in vinegar for ten minutes can protect your skin. ? 4 1. Wipe the mat in summer, and wipe the mat with water dripping from flower dew, which can keep the mat fresh and clean. Of course, it is best to wipe along the grain of the mat, so that the toilet water can penetrate into the grain gap of the mat, so that the cool and comfortable feeling will last longer; ? 42. Eating more acidic fruits and vegetables such as tomatoes and citric acid for breakfast is beneficial to nourishing the liver; ? 43. When washing your hair or taking a bath, adding five or six drops of toilet water to the water can play a good role in cooling and sterilizing, eliminating malnutrition and relieving itching; ? 44. Grapes contain sleep-promoting hormones, which are helpful for sleep when eaten regularly; ? 45. Drinking tomato soup in summer can not only get nutrition, but also replenish water. Tomato soup should be cooked and cooled before drinking. Lycopene contained in it has certain anti-prostate cancer and myocardial protection effects, and is most suitable for men to eat. Eating acidic substances and brushing your teeth immediately will damage your teeth health; ? 46. When the flesh is broken due to trauma, apply toothpaste to the wound to diminish inflammation and stop bleeding, and then bandage it. As a temporary first-aid medicine, medicinal toothpaste has the most remarkable effect; ? 47. Spraying white vinegar on the chopping block and washing it for half an hour can not only sterilize but also deodorize; ? 48. Drinking yogurt can relieve irritability after drinking. Yogurt can protect gastric mucosa, delay the absorption of alcohol, and is rich in calcium, which is particularly effective in relieving irritability after drinking; ? 49. When leather shoes are moldy for a long time, you can wipe them with a soft cloth dipped in alcohol and water (1: 1). ? 50. When you have a headache or dizziness, you can apply toothpaste to your temples, because toothpaste contains menthol and clove oil, which can relieve the pain; ? 5 1. Insert the candle into the birthday cake after freezing for 24 hours, and the candle oil will not flow down when it is lit; ? 52. White underwear turns yellow easily after washing. You can take a basin of water and drop two or three drops of blue ink. Soak the washed underwear for a quarter of an hour and put it in the sun. It can be white and clean without wringing it out. ? 53. Eat too much.

5. Daily popular science knowledge (simple)

1. Volatile organic pollutants such as benzene, toluene and xylene in furniture can lead to fetal congenital defects.

2. The most environmentally friendly detergent is soap. 3. 194 1 year, Chinese physicist Wang proposed an experimental scheme to verify the existence of neutrinos. Half a year later, American scientists conducted experiments according to this scheme and confirmed the existence of neutrinos.

4, put the sanitary ball in the closet, it will produce a certain sublimation, and it will become smaller after a while. When using air conditioner in summer, the temperature should be set at 26-28 degrees.

6, restaurant kitchen lampblack will produce pollution and harm to health, so you should install lampblack purification device. 7. Eating iodized salt can meet the human body's iodine intake. The salt people usually use is iodized salt.

Because of the volatility of iodine, we should seal the iodized salt. 8. Geothermal energy, wind energy, solar energy and other energy sources that can avoid air pollution after use are called clean energy.

9. Fragrant plastic book covers, pencils and other fragrant stationery are deeply loved by primary and secondary school students. But according to professionals, these pungent stationery will threaten human health because it contains a lot of formaldehyde.

10, nuclear power plants must always adhere to the principle of quality first and safety first. 1 1. Two thousand years ago, people thought that the earth was the center of the whole universe, until17th century, Galileo used his telescope to observe that the earth revolved around the sun.

12, the height from the ground, the less atmospheric molecules, the less light scattered by air molecules, so the sky becomes dark. 13. Wild animals contain a large number of parasites, which are easy to induce some parasitic diseases, such as cerebral cysticercosis, paragonimiasis and intestinal parasitic diseases.

14. The first flying man in the history of manned space flight in China was Yang Liwei. 15. It is best to soak the bought vegetables in clear water for 10-20 minutes, which can remove most of the residual pesticides.

/KOOC-0/6,/KOOC-0/96/KOOC-0/April/KOOC-0/2, the former Soviet Union astronauts traveled into space for the first time in the "Dongfang-1" spacecraft. 17, solar energy is solar radiation energy, and the surface temperature of the sun is about 6000℃.

18, 1964 China's first atomic bomb exploded successfully. 19, the only scientist who won the Nobel Prize twice in history was Madame Curie.

20, medical alcohol 75 degrees. 2 1, the folk ghost fire is actually the result of phosphorus spontaneous combustion in the air.

22. The cross section of an ordinary thermometer is circular, while the cross section of a thermometer is similar to a triangle. The thermometer of this shape is mainly used to enlarge the liquid column and facilitate reading.

23. When insects fly, their wings vibrate. Butterflies flap their wings 5-6 times per second, and bees flap their wings 300-400 times per second. When they are all flying behind you, you can feel the bees flying behind you by hearing. 24. In the human body, the most acidic liquid is gastric juice.

The former Soviet Union launched the first artificial satellite. 26. When driving, the speed of 80km/h is 25% less than that of110 km/h. ..

27. The child made a mistake when doing his homework. It's best to persuade him not to use correction fluid. 28, automobile exhaust contains nitrogen dioxide, carbon monoxide, hydrocarbons and other harmful substances.

29. Frost is when the temperature of an object or crop drops to 0? Below c, the water vapor in the air condenses directly on the objects or crops on the ground into white ice crystals. 30, 1954, the former Soviet Union built the world's first nuclear power plant.

3 1, and the core temperature is above 5000℃. It was the Wright brothers who invented the plane.

33. Nineteen ancient poems: Altair, Hehan female. Vega is located in Lyra.

34. The most representative constellation in the winter night sky is Orion. 35. Ding Zhaozhong, a famous Chinese-American physicist, won the 1976 Nobel Prize in Physics for his discovery of the long-lived heavy-mass meson.

36. The rated frequency standard of power system in China and most countries in the world is 50Hz, and that in a few countries is 60HZ. Comets are called "broom stars" and have a long tail like a broom.

38. The color of the sun is white. 39. Trees can absorb carbon dioxide and release oxygen through photosynthesis.

40. All the colors on the color TV screen are composed of three primary colors, which are green, red and blue. 4 1, China's hybrid rice is world-renowned, and Yuan Longping is known as the "father of hybrid rice" internationally.

42. According to the star area, there are 88 constellations throughout the day.