1. 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 muscles of the snake 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 beans and ketchup beans are all delicious canned foods, which can be preserved for a long time and are not easy to deteriorate. 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 will feel itchy and laugh constantly; 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 much different from the water we touch every day, and it is also transparent. The green we see is actually a phenomenon caused by the ability of seawater to absorb light. Only green light can be absorbed and reflected by seawater; When the seawater is deep, the green light is also absorbed, and the seawater looks blue.

16. Why do you get goose bumps?

Hair grows on the surface of our skin, and there is a vertical hair muscle under each pore. When stimulated by nerve (such as anger, fear, cold, etc. ), the body temperature will drop, the vertical hair muscles will contract, making the hair stand up and form goose bumps. In addition to keeping warm, this physiological system can make animals look bigger than they really are, thus scaring off enemies.

17. The hippocampus was born in dad's stomach?

Almost all animals are females, but the hippocampus is different. It's male. On the belly of the male hippocampus, there is an incubator similar to a kangaroo "pouch", and the female hippocampus will discharge the eggs into the incubator of the male hippocampus. Since then, the male hippocampus has assumed the responsibility of pregnancy. In about three weeks, the little sea horse will pop out of his father's body.

18. Why do leaves change color?

The reason why leaves change color is related to the chemical substance chlorophyll. When autumn comes, the days are shorter and the temperature is lower than that in summer, so the leaves stop producing chlorophyll, and the remaining nutrients are transported to the trunk and roots for storage. Leaves lack green chlorophyll and other chemical pigments appear at the same time, so we often see yellow and brown leaves.

19. Why are there leaves?

It's fall here. Leaves evaporate more water than in summer, but roots absorb less water than in summer. In order to reduce the water loss of trees, stem cells began to form separation layers. When the nutrients leave the leaves completely, the separation layer separates the leaves from the trunk and leaves fall off.

20. Why do whales spray water?

A whale is a mammal, but its nose has no shell, and its nostrils grow on the top of its head. Living in water and breathing with the lungs can store a lot of air at a time, and you don't need to breathe on the surface often. But when it breathes to the surface, it breathes through its nose. When it breathes, the huge sound waves emitted by the sea water are caused by pressure.

Life tips

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, and shine as new after drying; The ground polished by woolen clothes should be wiped with 50% vinegar water and then spread out with a wet cloth.

When the pad is ironed, the bright spots can be eliminated.

4. vinegar can also be used for disinfection and sterilization. Cold dishes mixed with vinegar, refreshing; Fumigating rooms with vinegar can sterilize and prevent influenza; each

Using 40% vinegar aqueous solution every day and washing your hair after heating can prevent hair loss and dandruff; Mix carboniferous ash powder with vinegar and apply it under your armpit every day.

The second time can cure body odor.

Wonderful use of eggshells

1. The mixture of egg white and water in fresh egg shells can be used to clean glass or furniture and add luster.

2. Put the broken egg shell and vinegar together in a bottle with dirt and shake it vigorously to remove the dirt.

3. Putting eggshells with white or yellow eggs around the planting holes in Hua Mu can provide a lot of nutrition for the roots of Hua Mu.

Promote the growth of flowers and trees.

4. Eggshell is rich in calcium. If it is ground into powder and mixed in the feed of chickens or pigs, hens will not become soft after eating it.

Shell eggs, pigs eat tendons and bones grow well.

Knowledge of putting monosodium glutamate

Don't put essence in sour dishes, such as sweet and sour fish, sweet and sour ribs, etc. Because the essence is alkaline, for example

Pickled sauerkraut with alkaline taste is chemically neutral, but on the contrary, it will produce salt and water, and it will also make plates.

Delicious dishes have lost their flavor.

Can it be added to alkaline food? Practice has proved that flavor essence is the same as glutamine disodium in alkaline food.

It will also lose its freshness. Therefore, the essence should be placed in unknown food, both acidic and alkaline.

Essence should also pay attention to the salinity of Italian food. If the fruit is too salty, the sodium ions in the salt cover the sodium acid and cannot be eaten.

Tastes delicious; If the fruit is too light, the taste is thin and fresh.

Finally, pay attention to the temperature. The solubility of essence is 85 degrees. Below this temperature, the texture of flavor is indistinguishable.

Solution, above this temperature, essence should not be put, otherwise it will have no fresh taste.

Identification of honey quality

Honey should be light.

Honey is a good honey because it contains many white particles and crystals and contains more glucose.

Honey water is extremely thin, its capacity is easy to flow, and its fragrance is not strong, but it can be mixed with water.

Fill a small spoon with honey. The dripping honey is broken and will quickly shrink into the spoon. It shows strong toughness and is a good honey.

Put a spoonful of honey in the cup and add four to five times of hot water to dissolve it. If there is no precipitation after standing for 3-4 hours,

This is pure honey, good honey.

Among bee honey, loquat honey is the best, followed by purple stone honey, pear honey, cauliflower honey, and buckwheat honey is the worst.

In addition, some honey sold in the market is mixed with water or other impurities, which can be identified by the following methods.

Distinguish between mixing honey with water and sucrose: drop honey on white paper or toilet paper. If the honey water on the paper is gradually oozing out, that's clear.

Mix sucrose and water.

Identification of honey water mixed with precipitation powder: put a small amount of honey water into a cup, add a proper amount of water, boil, wait for cooling, and then drop a few drops of iodine.

Wine, such as fruit juice, turns blue, indicating that it is mixed with lake powder.

Honey mixed with impurities: insert red-hot iron wire into honey. If there is a sticky substance on the wire, it means that there are impurities in it.

Quality; If the wire is still smooth, it means there are no impurities.

The magical use of beer

1. Dilute flour with beer. Poured on sliced or shredded meat, fried meat is tender, especially in this way.

Boiling beef is more effective.

2. Beer can add delicacy to cold tea. Soak vegetables in beer and cook them. When the wine boils, take it out and add some notes.

seasoning

3. Mix some beer in the water when mixing dough, and the baked pancakes are crisp and fragrant.

4. Knead a proper amount of beer into the dough of the baked dough bag. Bread is easy to bake and tastes close to meat.

Tao.

5. When cooking fat meat or fat fish, add a glass of beer to get rid of the greasy taste, and it tastes good.

6. Put the chicken to be cooked in salt, pepper and beer and soak it for 1 ~ 2 hours to remove the fishy smell of the chicken.

Distinguish between true and false monosodium glutamate skillfully

It is not difficult to distinguish between true and false tastes. You can take a small amount of essence and put it on the tip of your tongue. If your tongue feels cold, it tastes fresh.

Those beautiful and fishy are classified as good products; If it tastes bitter and salty and has no fishy smell, it means that this essence is mixed with edible salt; if

If you feel cold, slippery, sticky and difficult to dissolve after tasting, mix it with gypsum powder or wood potato powder.

Cleverly remove the dirt on the inner wall of the teacup

After the cup is used for a period of time, the inner wall will be firmly attached with a layer of dark yellow sediment, which is in tea.

Vitamin C tablets can effectively remove the precipitate formed by the combination of insoluble egg white substances and pigments.

They: don't drink warm water in the cup, mash a few vitamin C tablets and put them in the cup. After stirring, soak the inner wall with water solution.

Then, put your finger on the vitamin C tablet and gently rub the inner wall to remove the scale.

In addition, wiping the cup wall with toothpaste can also remove tea stains.

Clever choice of tea

1. Look at uniformity. Pour the tea leaves into the tea tray, and turn the tea tray several times in a certain direction by hand to make different shapes of tea leaves.

Hierarchical. The more tea leaves in the middle stage, the better the uniformity; On the contrary, the uniformity is poor.

2. Look at the color. Green tea has good quality and bright green color; Black tea is of good quality, brown and oily. Ru LV cha Han

White hair is more, and black tea contains more orange buds, all of which are high-grade teas.

Look at that loose rope. Tight and heavy quality is good, thick and loose, and fine and broken quality is poor.

4. look clean. There are many tea stalks, leaf stalks, tea seeds and impurities in tea, and the quality is poor.

How to identify eggs

Light identification: when light is used, fresh eggs are clear and transparent, and the dividing line between clear eggs and yellow eggs is clear. The empty head is small, orange-red, and there are no eggs in it.

Black spots, no red shadow; Stale eggs are yellow or black, yellow and clear are difficult to distinguish, while bad eggs have large pieces of black.

Cold water identification: put the eggs in a basin filled with cold water. If an egg lies on the bottom of the water, it is a fresh egg. If the egg tilts in the water.

The middle means that the eggs have been stored for three or five days. If an egg stands upright in the water, it is an old egg. If the fruit floats on the water, it is likely that

It has changed.

Rotation identification: put the egg on the ground and gently rotate it by hand. The fresh egg stops rotating for two or three weeks, and the bad egg turns.

Fast duration is long. Stale eggs become neither fast nor slow.

Touch identification: hold the egg in your hand and shake it gently. No noise is a good egg, and noise is yellow or close.

High quality eggs.

The magical use of salt

1. To make the flowers bloom more brightly, just pour a little salt water into the flowerpot.

Washing chilblain with salt water can relieve itching.

Drinking a glass of light salt water in the morning helps to relieve constipation.

Rub salt water on the scalded skin to relieve the pain.

Putting some salt in the water when taking a bath can cure skin diseases.

6. When frying food in oil, put a little salt in the oil pan so that the oil won't overflow.

7. When you cook a cracked egg, put some salt in the water so that the egg white won't flow out.

8. Mash carrots, mix some salt and wipe off blood stains on clothes.

9. In order to prevent clothes from fading when washing clothes, you can put some salt in the water.

10. Glass cups or porcelain bowls cooked with salt water are not easy to crack.

1 1. Wipe off the black spots on the bronze with salt.

Wonderful use of Taomi water

1. Washing light-colored clothes with washed rice is easy to remove dirt and has bright colors.

2. The precipitated rice washing water can be used to make clothes by adding hot water.

Wash your hands with rice washing water, which can be used to moisturize your skin.

4. Rinsing your mouth with Taomi water can cure bad breath or oral ulcer.

5. Wash the fishy dishes with salted rice water, and then rinse with clear water to remove the fishy smell.

6. Soak the bacon in rice washing water for half a day to remove the salty taste.

7. Washing bacon with rice is better than washing it with water.

8. Washing pork belly with washed rice is more energy-saving, labor-saving, clean and economical than washing with salt or bone alum.

9. Kitchen knives that are often soaked in rice washing water are not easy to rust. Rusty kitchen knives are easy to rub when soaked in rice washing water for several hours.

Clean.

10. Taomi water can make flowers or vegetables grow stronger.

1 1. Washing furniture with rice is brighter than before.

12. Wipe the new lacquerware with rice washing water for 4 ~ 5 times, and the odor can be removed.

Selection of toothpaste

At present, there are two kinds of toothpaste on the market: ordinary toothpaste (tooth cleaning toothpaste) and medicinal toothpaste.

Yao Yao ointment has developed rapidly in recent years, with a wide variety. According to their functions, there are mainly the following:

1. Toothpaste, anti-aging drug. Its special ingredients can reduce the erosion of enamel by lactic acid in oral cavity, and make enamel

It has the characteristics of acid resistance, kidney hardness and wear resistance, and can be used to prevent and treat "tooth decay".

2. Anti-inflammatory and hemostatic toothpaste. Mainly to prevent and treat oral diseases such as periodontal disease and gingival bleeding. Periodontitis and gingivitis

The symptoms are bleeding gums, deepening periodontal sulcus, inflammation and atrophy of periodontal tissue, which makes the roots loose and unable to chew.

The use of toothpaste, an anti-inflammatory and hemostatic drug, mainly inhibits the formation of dental calculus and plaque, or can change organic teeth.

Incidental energy The main drugs used in this dental ointment are Baicao, Zanthoxylum nitidum and Tianqi.

3. Desensitized medicine tooth ointment. Mainly to prevent and treat tooth allergy to cold, heat, acid and sweetness. This toothpaste

Effective components are absorbed by enamel and dentin, which can reduce the permeability of tooth hard tissue, improve the slow impact of tooth tissue, and increase

Combined with the disease resistance of periodontal tissue, desensitization can be achieved. Acid-resistant toothpaste and desensitizing toothpaste all belong to this category.

In addition, toothpaste, toothpaste with enzyme, toothpaste to prevent infection and eruption are not suitable for people in need.

Various types of dental ointments are also produced and sold, and consumers can choose according to their own conditions.

How to applaud toothpaste?

1. The thickness should be appropriate, so that the strips can be extruded from the hose, and the teeth can be covered without spilling.

2. The rubbing strength should be moderate, and it should have a good tooth cleaning effect, but it will not hurt the tooth glaze.

3. The paste is stable. During storage, there is no precipitation, hardening and dilution, and the pH value is stable.

4. Yao Yao ointment should keep its curative effect within the validity period.

5. The paste should be clean and beautiful without bubbles.

6. There are proper bubbles in the process of brushing teeth, which can easily eliminate the floating of food residues.

7. The fragrance and taste should be appropriate.

Several misunderstandings in diet

1, like to drink new tea:

Although Shixin tea has fresh leaves and mellow taste, it contains more non-oxidized polyphenols, aldehydes and alcohols, which are easy to be induced.

Symptoms such as abdominal distension and abdominal pain aggravate the condition of patients with chronic gastritis.

2. Stir-fry vegetables in an overheated oil pan:

In an overheated oil pan, it is easy to produce a hard fat compound. If people often eat vegetables fried in hot oil pan, it is easy to have low acidity.

Sexual gastritis and gastric ulcer, if not treated in time, can also induce gastric cancer.

3. Raw water-cooled eggs:

Soak the boiled eggs in cold water. Although the shell of an egg is easy to peel off, there is still a chance for sick bacteria. If you want to make eggshells easy to peel, only

You need to add a little salt to the boiled egg water.

4, eat fruit immediately after a meal:

Fruit contains a lot of monosaccharides. If it is blocked in the stomach by rice and vegetables, it will be flatulent due to decay, leading to

Stomach upset. So eat fruit one hour before meals and two hours after meals.

5, add more seasoning to adjust the taste.

Natural flavoring products such as pepper, cinnamon and incense. It has certain mutagenicity and toxicity, and it will bring people dry mouth, dry throat and dry throat if it is used many times.

Side effects such as pain, listlessness and insomnia can also induce diseases such as hypertension and gastroenteritis, and even lead to abnormal human microcells.

Become cancerous.

How to distinguish true and false green food

Real green food, the upper part of the package has green food signs and belts. The adhesive tape is close to one end of the logo, that is, the left side.

Printed with the words "green food", the font is standard font, and the standard batch number of green food is also printed at the bottom. If the fruit is in the package.

If there is no such green food logo and label on the dining table, it is fake green food.

Real green food, signs and tapes have a clear contrast with the height of packaging. This comparison is defined as

1: 6.8, and printed with the words "China Green Food Development Exhibition allows the use of green food". If the fruit is marked,

Zhihe label, but inconsistent with the packaging height, is still a fake green food.

Real green food, the outer packaging is designed according to the requirements of the national labeling law. On its outer packaging, it is printed with

The label, name and location of enterprise products. The outer packaging that is not stipulated in the National Standards Law shall be set up.

If there is no enterprise product label, enterprise name and location, it is counterfeit green food.

Real green food makes the imitation of green food false. This kind of anti-counterfeiting logo can also be clearly displayed under fluorescent lamp.

Show the standard document number of the product and the autograph of Liu Lianfu, chairman of China Green Food Development Exhibition. If there is no green

Foods with anti-counterfeiting labels, or those with anti-counterfeiting labels without signs under fluorescent lamps, are all fake green foods.

There is a unified anti-counterfeiting mark on the packaging of products with "green food" logo, which makes the development of green food in China become the center.

The serial number on the label should be the same as that on the product packaging. Otherwise it can be regarded as fake "green food".

For the happiness and health of you and your family, please choose and buy the green food approved by China Green Food Development Exhibition!

How to wash rice is the most reasonable.

Soak rice in cold water with tap water or plain water first, then remove impurities from rice, and then bleach it quickly with clean water.

Just wash it. It is not advisable to use too much water to avoid nutrient loss. If the fruit and rice are seriously moldy, the moldy rice should be removed first.

Grain, but then put it into rice according to the above method, don't wash it with water, rub it with your hands for 3-4 times, this food is safer than eating.