Little knowledge around you

1. 50 little scientific knowledge around you

Science around you As long as you pay attention, science is everywhere.

On Saturday, the teacher assigned an assignment to do a scientific experiment. I thought about it and finally came up with an experiment. I want to do a scientific experiment that eggs will float.

Prepare a cup, an egg and some salt. Put water, eggs and salt in the cup first.

It's strange that the egg didn't float at this time. As soon as I thought about it, I added salt to the cup in spoonfuls.

After adding a few spoonfuls, I found that the eggs began to float slowly. Gradually, the eggs rose to the surface like an elevator.

Why do eggs float from salt water? Because after adding salt to the water, the density of salt water becomes larger, and the buoyancy is greater when the density is larger, and the eggs can be held up when the buoyancy is greater. This scientific experiment is really interesting. I'll try again.

Chapter 2: Science around me One night, my mother bought a bag of metapenaeus ensis. The base-tailed shrimp is blue, but the cooked base-tailed shrimp turns red. I asked my mother. My mother didn't tell me the answer directly, but gave me a book, Question and Answer, to find the answer by myself. I looked for it and finally found it, because there is a pigment called astaxanthin in shrimp. Usually mixed with other pigments, it can't show its bright red color, but after heating, all other pigments are destroyed and decomposed, except astaxanthin, which is not afraid of high temperature, so shrimp turns red after cooking.

It turns out that there is science everywhere in life! Chapter 3: Science around us Speaking of science, in fact, many things happening around us are solved by science. Let me give you a simple example.

I remember once, my mother asked me to open the vinegar bottle when I was cooking, but I just couldn't unscrew it. Later, my mother told me that it was easy to unscrew the vinegar bottle by soaking it in hot water for five minutes and then washing it with cold water.

In this way, I tried to do it in my mother's way. Sure enough, the vinegar bottle was easily unscrewed.

My mother told me that this is the effect of heat expansion and cold contraction. After this incident, I sincerely thank science, which makes me progress and helps me grow.

2. What common sense of life do you have around you?

1, washing clothes neckline: sprinkle some salt powder on the neckline, rub gently, and rinse off the salt with water. Because human sweat contains protein, it is insoluble in water, but can be quickly dissolved in salt. 2, make the toothbrush durable: soak the newly bought toothbrush in hot salt water for about half an hour and take it out, which can make the toothbrush durable. 3, egg white adhesion and small porcelain, glass: If the small porcelain and glass are broken, you can cover the two broken surfaces with egg white, wipe off the excess egg white around after sewing, and after half an hour, the broken parts can be completely adhered. After standing for a day or two, it will be rubbed by a large external force, and the adhesion will not break. 4. Pots, cups, cups and other porcelain with tea stains, oil stains and water stains can be removed by soaking lemon belt residue with juice in a bowl of warm water for 4 or 5 hours. Washing with vinegar and salt can also be very clean. The Mid-Autumn Festival is coming. Here is some food. 1, fry fish without touching the pan: wash the pan, dry it, heat it, then put oil in it, and then turn it over to make it full of oil. You don't touch the pot when frying fish. 2. Save frying steamed bread: first prepare a bowl of cold water, slice the steamed bread, soak the steamed bread slices in water when frying, and immediately put them into the pot for frying, so that the fried steamed bread is golden in color, tender outside, delicious and fuel-efficient. 3. Identify the quality of canned food. After cooking, the water in the can becomes steam, and after sealing and cooling, the steam condenses into water. The air in the tank becomes thinner, and the external atmosphere collapses the top of the tank. So the top of a good can is not flat, but slightly concave. If the food in the can goes bad and produces gas, the top will protrude. 4, old photos become new: photos are old or dirty, wipe with cotton dipped in alcohol, it will be the same as brand new. 5, glasses anti-fog: when it is cold, glasses are easy to fog when they are hot, making people see things. You can wipe both sides of the lens with semi-dry soapy soil and then wipe it evenly. In this way, even if you take a bath in the bathroom, the lens will not fog. How to quickly untie the tangled necklace * * * You can sprinkle some talcum powder first and start to untie it. The chain is smooth because of talcum powder, and it is easy to separate no matter how tightly it is wrapped. * * * Ways to prevent the bath water from getting cold * * * When taking a bath in winter, the water is easy to get cold. You can add a little salt to the bathtub. Salt can temporarily block the sweat line, so the heat in the body will not be emitted. * * * How to eliminate the cracks on the plate * * * You can put the plate in a pot, pour in milk and heat it for four to five minutes. After the milk is boiled, you can turn off the fire and take out the plate, and the cracks almost disappear. * * * Moisture-proof methods for biscuits * * * When the biscuits are canned, put a cube of sugar at the same time. Because the sugar cube will absorb the water in the jar, it can keep the biscuits crisp and delicious. * * * Ways to prevent the boiled noodle soup from overflowing * * * When cooking, add cream or a little salad oil to the soup. At the same time, keep the soup boiling, and do not add cold water when cooking other noodles. * * * How to remove the smoke stains on your fingers * * * The most effective way is to scrub with lemon juice. At first, the effect is not obvious, but after patiently wiping, the color will gradually fade. If it still doesn't work, you can add a little hydrogen peroxide to the lemon juice and the effect will come out. * * * How to restore the shrunk sweater to its original state * * * Inject warm water into the washbasin, drop a small amount of household ammonia water, and then soak the sweater, and the soap left on the wool will dissolve. Gently stretch the narrowed part with both hands at the same time, and then rinse it to dryness. When it is half dry, first open it by hand, straighten it, and iron it with an iron to restore its original size. * * * How to remove the furniture marks on the carpet * * * Eliminate the common dent marks on the carpet. Try spraying steam into the dent with a competitive iron, or spread a wet towel in the dent and iron it. Then use a hard toothbrush to stir up the hair in the recess, and then brush it gently. * * * Enzyme-containing laundry detergent can't use hot water * * * Enzyme-containing laundry detergent is the most effective for protein dirt produced by the body, but protein will deteriorate and stick to the cloth when heated. Even if it is enzyme laundry detergent, there is nothing we can do. So the water temperature is still limited to 30 to 60 degrees. * * * How to prevent sweaters from shrinking * * * The principle of washing sweaters is that the sooner you wash them, the better. Generally speaking, the less laundry detergent is used, the easier it is for sweaters to shrink, so it's best to add more laundry detergent to prevent sweaters from getting smaller. * * * How to make transparent and clear ice cubes * * * is to fully boil the water and pour it into the ice maker. Because of this, impurities such as lime in water can be evaporated, and the ice cubes made will be particularly transparent. * * * The secret of making a vase durable in summer * * * You can drop a drop or two of bleach into the vase. Bleaching water has the function of disinfecting fruits. Although the water temperature is high, it can also make the incision of the flower stem difficult to breed bacteria, and the flower is naturally more durable.

3. Little common sense around you

1. Use toothpaste skillfully: If there is a small area of skin injury or burns, applying a little toothpaste can immediately stop bleeding and relieve pain, and also prevent infection, with good curative effect. 2. Skillfully remove the greasy screen window: You can put the washing powder and cigarette butts left over from smoking together in the water, and use them to clean the glass window and screen window after dissolution, which has a good effect. 3. Put the shrimp in a bowl, add a little salt and edible alkali powder, rub it with your hands for a while, then soak it in clear water, and then wash it with clear water. This will make the fried shrimps transparent as crystal, refreshing and delicious.

4. There is also the unique skill of jiaozi noodles: 6 egg whites are mixed into 1 kg flour to increase the protein in noodles. Protein will solidify and shrink quickly after jiaozi takes the pot, and jiaozi will collect water quickly after taking the pot, which is not easy to stick.

5. After soaking tea in water for a few days, pouring it on the roots of plants can promote the growth of plants; Residual tea leaves can be dried in the sun and smoked in toilets or ditches, which can eliminate the stench and drive away mosquitoes and flies.

6, uncooked rice re-cooking method: If the rice is raw, 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 simmer again. If it's just unfamiliar, turn the noodles to the middle and simmer.

If you have to cook vegetables, you'd better make full use of boiled water. When cooking jiaozi, you can put a proper amount of boiling water in the meat stuffing, which not only retains the nutrition, but also makes the dumpling stuffing delicious and the soup delicious.

8, the trick of scrambled eggs: beat the eggs in a bowl, add a little warm water and stir well, pour into the oil pan and fry, drop a little wine into the pot when frying, so that the scrambled eggs are fluffy, tender and delicious.

9. How to use the casserole 1: When the newly bought casserole is used for the first time, it is best to cook porridge, or use it to cook concentrated rice washing water to block the tiny pores of the casserole to prevent water seepage.

10, skillfully using "Thirteen Fragrances": use dried tangerine peel when stewing meat, which is rich in flavor; Eating beef and mutton with angelica dahurica can remove fishy smell and increase freshness; Cinnamon for homemade sausage is delicious; Bacon smoked chicken with cloves has an endless aftertaste.

4. What little scientific knowledge do you have around you?

You should eat bread before drinking milk.

Milk is a kind of natural food with the most comprehensive nutrition, the most appropriate proportion and the easiest digestion and absorption by people. But drinking milk is very particular.

If the method is improper, the effect will be greatly reduced. Experts believe that drinking milk is the best.

No sugar. Otherwise, it will not only be difficult to be digested and absorbed, but also stay in the digestive tract, affecting gastrointestinal function. Milk can be heated, but not boiled. because

After boiling, some vitamins will be destroyed, and calcium in milk will form calcium phosphate precipitation, which is not easily absorbed by the human body. Don't just drink milk for breakfast. Drinking milk on an empty stomach will accelerate gastrointestinal peristalsis and cause malabsorption. The correct way is to eat bread, cakes, etc. First, then drink milk, which will make the nutrition more balanced. At the same time, don't eat chocolate while drinking milk. Because oxalic acid in chocolate will combine with calcium in milk to form calcium oxalate, calcium can not be fully absorbed by human body.

Why does milk have a layer of skin after heating?

The skin floating on the surface of milk is solidified, protein. Milk contains all the nutrients necessary for the growth and development of cattle, and protein is one of the most important nutrients. Once heated, protein will solidify. Cooked eggs will solidify, because the protein in the eggs will solidify. Protein in milk will also be solidified by heating. Protein, especially protein in milk, will solidify when it goes bad even if it is not heated. Protein spoilage will produce acid, which can solidify milk. Although yogurt solidified with lactic acid bacteria can be eaten, it is best not to eat naturally deteriorated and solidified milk, because we don't know what kind of bacteria it will contain, which will make people sick.

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. 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. Why does cicada shed its 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. How do bees make honey? First, the bees spit the sweet juice of the flowers they picked into an empty hive. At night, they suck sweet juice into their honey stomachs to make it, and then spit it out and swallow it. It takes 100~240 times to make sweet honey. How do birds sleep? During the day, birds shuttle in the branches, chirp and fly freely under the blue sky. At night, they should rest, sleep and recover their strength like us, but the sleeping posture is different! Beautiful mallard ducks and swans hunt and play in the water during the day, but they can't rest when they leave their favorite water at night. They bend their beautiful long necks, bury their heads in their wings, and then let themselves float on the water, dreaming a beautiful dream and drifting with the tide, which is very leisurely. Long-legged birds such as cranes, storks and herons always sleep independently on one foot, and when they are tired, they change their other feet, which is a model of combining work and rest. Partridges like to form a big circle in groups when resting, and then their heads are outward and their tails are inward. In this way, no matter which direction the enemy attacks, they can find and escape in time. Birds with sweet voices, such as blackbirds and larks, usually bend their legs when sleeping, and their claws bend to firmly grasp the branches without worrying about falling from the trees. And the owl, a "night-shift" raptor, you can always see it standing on a dense branch with one eye open during the day, actually sleeping. Isn't the owl's sleeping position very different? Is to monitor the surrounding environment at all times and guard against enemy attacks.

5. 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 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 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 move on.

6. There is little scientific knowledge around us.

Common sense category:

Science around us: Why do you see lightning first and then hear thunder?

Because light waves travel faster in air than sound speed.

Science around us: Why can't we turn off the lights and watch TV?

The screen and image of TV are relatively small. In the dark, the vision should be highly concentrated and expanded, and it is particularly sensitive to the strong reflection of light on the TV screen, which will make the eyes suffer from * * * and the vision will decline.

Science around us: Why should we install a black box on the plane?

A: It is used to record various situations on the plane during the crash and help people understand the cause of the accident.

Science around us: Why does the bicycle move?

Bicycle tires rub against the ground.

Science around us: Why does the wind make a "swish" sound when it blows?

When a strong wind touches something as slender as wires or branches, it will make a "swish" sound. The slender whip shakes violently in the air, and a vortex of air is formed behind the whip, which makes the air vibrate and make a sound. The way the wind blows branches is like waving a whip. When the wind blows at an acute angle or behind the gap, it will also form this vortex and make a "swish" sound, and the tone will be different according to the strength of the wind.

Science around us: How do bees make honey?

First, the bees spit the sweet juice of the flowers they picked into an empty hive. At night, they suck sweet juice into their honey stomachs to make it, and then spit it out and swallow it. It takes 100~240 times to make sweet honey.

7. 50 little scientific knowledge around you

The science around you

As long as you pay attention, science is everywhere.

On Saturday, the teacher assigned an assignment to do a scientific experiment. I thought about it and finally came up with an experiment. I want to do a scientific experiment that eggs will float.

Prepare a cup, an egg and some salt. Put water, eggs and salt in the cup first. It's strange that the egg didn't float at this time. As soon as I thought about it, I added salt to the cup in spoonfuls. After adding a few spoonfuls, I found that the eggs began to float slowly. Gradually, the eggs rose to the surface like an elevator.

Why do eggs float from salt water? Because after adding salt to the water, the density of salt water becomes larger, and the buoyancy is greater when the density is larger, and the eggs can be held up when the buoyancy is greater.

This scientific experiment is really interesting. I'll try again.

Chapter 2: Science around us

One night, my mother bought a bag of shrimp. The shrimp is blue, but the cooked shrimp turns red. I asked my mother. My mother didn't tell me the answer directly, but gave me a book, Question and Answer, to find the answer by myself.

I looked for it and finally found it, because there is a pigment called astaxanthin in shrimp. Usually mixed with other pigments, it can't show its bright red color, but after heating, all other pigments are destroyed and decomposed, except astaxanthin, which is not afraid of high temperature, so shrimp turns red after cooking.

It turns out that there is science everywhere in life!

Chapter 3: Science around us

Speaking of science, in fact, many things that happen around us are solved by science. Let me give you a simple example.

I remember once, my mother asked me to open the vinegar bottle when I was cooking, but I just couldn't unscrew it.

Later, my mother told me that it was easy to unscrew the vinegar bottle by soaking it in hot water for five minutes and then washing it with cold water. In this way, I tried to do it in my mother's way. Sure enough, the vinegar bottle was easily unscrewed. My mother told me that this is the effect of heat expansion and cold contraction.

After this incident, I sincerely thank science, which makes me progress and helps me grow.

8. Some common sense and science around you.

If the cover of a book has been rolled up for a long time, it is because the humidity in the air is constantly changing; Because the paper of the book absorbs the moisture in the air, it begins to "evaporate moisture" when the air is dry, and it begins to absorb moisture when the humidity in the air is high, so it is easy to "deform" the paper fiber by constantly absorbing and evaporating moisture, so the paper will curl.

Lever principle.

Using the lever principle, using chopsticks not only saves labor, but also saves distance, making the operation more flexible, but it is more laborious (it doesn't matter if you spend a little effort).

The strength and resistance of the lever refer to the force exerted on the lever, the strength refers to the force exerted by fingers on chopsticks, and the resistance refers to the force exerted by vegetables on chopsticks. To determine the relationship between the force arm and the resistance arm of chopsticks, we need to find the fulcrum. The fulcrum is at the upper end of chopsticks, and the power arm is smaller than the resistance arm. Chopsticks are a laborious lever.

They are all laborious levers. Because the position of food is on the head of chopsticks.

You can feel it with chopsticks.

Its fulcrum should be in the tiger's mouth (index finger and thumb are connected).

Power is the force exerted by fingers on chopsticks, which is generally up and down at the midpoint of chopsticks (even if it is taken down, it can't reach the chopstick head).

Resistance is the force that prevents chopsticks from closing, which generally acts on the head of chopsticks. Unless you put the dish in the middle alone, it will not be used normally. )

Therefore, the power arm is a lever with less water than the resistance arm, which is a laborious lever.

Different people hold chopsticks in different postures, which will cause different degrees of exertion, but they are all laborious levers.