Scientific knowledge is urgent, urgent

12 practical tips for life.

**Nosebleeds**

If you have a nosebleed, if your left nostril is bleeding, blow into your right ear to stop the bleeding immediately! Vice versa. Don't ask me what to do if both nostrils are bleeding, if you are really that miserable, I suggest you go to the hospital.

Silk scarf cushion pillow hair does not deform**

Every girl has this kind of trouble, and after finally going to the beauty salon to get her hair done, after waking up, her hair is out of shape! In fact, this situation is preventable, as long as you spread a smooth silk scarf on the pillow before going to bed, so that you will not mess up your hair, and you can maintain a beautiful hairstyle!

**Acne**

Go to the supermarket to buy cassia seeds, soak them after dinner every day, and the acne disappears the next day, the lower abdomen is flat, and the weight is also reduced!

Ways to get rid of blackheads**

In fact, after washing your face, you can gently rub your fingers with some fine salt on both sides of the nose, and then rinse it with water, the blackheads will be cleared and the pores will become smaller.

Hair dryer for easy label removal**

When buying a gift box to give away, the price label is difficult to tear off, and the black and dirty ones that will be picked by hand are even more ugly, if you use a hair dryer to blow it hot and then tear it, it will be very easy to tear it off, leaving no trace!

Apply cream to the wound before bathing**

If you have a wound on your body when you take a bath, it will hurt if you touch water, and if you are not careful, it will become inflamed, so you can apply oil to the wound, such as a cream, and isolate it from the water, and it will not hurt!

How to identify fresh eggs? **

Fresh eggs are illuminated with lights, the short head is very small, the egg is completely translucent, orange-red, there are no black spots in the egg, no red shadow. To measure the freshness of an egg, soak it in cold water. If the egg is lying flat in the water, it is very fresh; If it is tilted in water, the egg has been stored for at least 3 to 5 days; If it is left upright in water, it may be stored for up to 10 days.

In addition, if the egg is floating on the water, it is very likely that the egg has gone bad.

Perfume spray mosquito**

If there are mosquitoes on the outside of the screen, it means that your home has been targeted by mosquitoes. If the mosquito is not removed quickly, it may wait for an opportunity to enter. Don't spray with pesticides, firstly, it may blow into the house with the wind, which is harmful to the human body, and secondly, the pesticides will adhere to the gauze net, and the smell will not dissipate for a long time.

You might as well spray it with perfume a few times, and the mosquitoes will immediately fall to the ground, leaving behind a much better smell than insecticide.

Egg whites work**

At this time, you can use egg whites to stop bleeding, apply the egg whites on gauze, and then apply them to the wound, because the protein ingredients have the effect of coagulating the blood and can stop the bleeding.

**Canker sores**

If there is an ulcer in the mouth, apply vitamin C to the ulcer and wait for it to dissolve, and the ulcer will basically be cured.

Chase away the dust from your eyes**

If you close your eyes and cough vigorously a few times, the dust in your eyes will come out on its own.

**Hiccups**

When you burp, roll a paper twist with a strip of paper, poke it in your nose, and stop sneezing a few times!

Does this count?? Hope it helps.

There is a lot of scientific knowledge, such as how to avoid sunburn under the scorching sun, how to avoid being struck by lightning during thunderstorms, how to escape scientifically after indoor fire, how to save people and save themselves after drowning, etc. I don't know what you need, but I hope to give an example.

Anti-magnetic cannons.

Materials: 4 round magnets Small xylitol jars.

Method: 1. Put the two magnets together and put them in a small xylitol jar 2. Put the rest together 3. Put the two groups together with force that is not easy to put together, and then suddenly let go, o k

1. Shrinking, inverted, real image; magnification, handstand, real image; Enlarged, upright, virtual image 2, zoomed out, inverted, real image.

3、f＜15cm

4. Enlargement, handstand, real image.

5. Stay away from the back.

cm＞f＞9cm

① a.Handstand shrinks solid bHandstand magnified real cUpright magnified void.

Handstand shrinks solid.

Less than 15cm

Handstand magnified solid.

Stay away from shrinking.

Hello friend, the answer to question 1 is A is an inverted and reduced reality, B is an upright, enlarged reality, and C is an upright, magnified virtual image. Question 2: Since the focal length is twice as long as 30cm, 60cm> 30cm, the real image is reduced upside down 3 questions are 30cm>2f, f<15cm. 4 questions are inverted to zoom in on the real image, 5 questions are far away, film.

6 questions: 9cm> f>6cm

There is science everywhere in life, but I just don't pay attention to it. People's clothing, food, housing and transportation in daily life are also inseparable from science, and as for production, labor, sports, health, and military, science is needed. "Be proud of advocating science and be ashamed of ignorance" There are many conventional common senses in daily life, which are all the experience of predecessors.

As a result, we mechanically take this common sense of life for granted to be correct and beneficial, and often do it without thinking. Over time, it becomes a habit, and it also makes your life troublesome, because these so-called "experience" and "common sense" are precisely contrary to the common sense of life, and to believe in science, only by respecting science, it is possible to avoid taboos and be less troubled by its troubles.

In winter, when the weather is cold, the glass bottle cap often cannot be unscrewed, and no matter how hard it is used, it will not work, and experienced people only need to put the bottle cap on the fire to roast. It can be easily unscrewed. Do you know why?

This is the principle of thermal expansion and cold contraction. When the weather is cold, the cap shrinks, and it is not easy to unscrew the bottle by biting the mouth of the bottle tightly, and when the fire is heated and expanded, the cap is loosened, so it can be opened without much effort.

When the old man struggled to thread the needle, she put the needle in her hair and wiped it, do you know why? It's actually lubrication and friction. Human hair contains oil, and when the needle is rubbed with oil, it is equivalent to adding lubricating oil, so it can reduce friction and can easily thread the needle.

Luncheon meat, dace with tempeh, tomato sauce beans, ......They are all delicious canned foods, and they can be stored for a long time without being easy to spoil. This is because the cans are sealed, so bacteria cannot enter. When people make canned food, they extract all the air from the can and seal it.

In the absence of air, even if the food inside is stained with a few bacteria, they will not be able to survive or multiply! This makes use of the air in the conditions in which the microorganisms live.

Some foods cannot be heated with high temperatures, otherwise their nutrition and taste will be affected. For these foods, we can quickly heat them to a certain temperature (usually 60 85) for 15 to 30 minutes, and then cool them quickly. This kills most of the microorganisms in the food while maintaining its original taste.

This heating method is called Pasteur sterilization, which was invented by the French scientist Louis Pasteur (Louis Pasteur), science to study various natural phenomena and find the causes and laws of their emergence and development. Every small question has the potential to lead to a scientific discovery. Lsaac Newton was curious about the apple falling to the ground and discovered the law of universal induction; James Watt was curious to improve the steam engine by lifting the lid after the water had boiled.

As long as we pay attention to the observation and start from the problems around us, we can all enter the world of science. Science is all around us. Resources.

Why is the trunk round.

In the process of observing nature, I stumbled upon the shape of tree trunks that are almost round—empty cones. Why is the trunk conical? What are the benefits of a conical trunk? In order to explore these questions, I conducted more in-depth observation, analysis and research.

I looked up the information and learned that the stems of plants have the function of supporting the plant body and transporting water and other nutrients. The stems of trees are mainly made up of vascular bundles. Although the stems of woody plants will thicken year by year, the number of wood fibers of the stems is certain within a certain time range, that is, the cross-sectional area of the tree stems is certain.

Next, we designed experiments around the cross-sectional area of the trunk, assuming that the cross-section of the trunk grows into different shapes, to explore the reasons and advantages of the conical shape of the trunk.

After experimentation, I found that:1When the cross-sectional area and length are constant, the longitudinal support force of the triangular prism object is the largest, and the transverse bearing force is the smallest. The longitudinal support force of cylindrical objects is not as good as that of triangular prism objects, but the transverse bearing force is the largest; Trunks of different shapes of equal mass, the short cone-shaped trunk withstood the most wind; 2.

Wind is a natural phenomenon that affects the shape of the cross-section of trees and the height of tree growth. The trunk is almost conical, with a low center of gravity, and with a large root system connected to the earth, the center of gravity is lowered lower and the stability is greater; 3.The trunk has a rounded cross-section, which reduces damage, has greater mechanical strength, and can withstand the attack of wind.

At the same time, due to the influence of wind, the degree of bending of the trunk is similar, regardless of the direction from which the wind comes from, the resistance of the trunk is similar, and the trunk is not easily damaged.

The above experiments reflect the laws of nature and the enlightenment of nature: a columnar object with a triangular cross-section has the maximum longitudinal support force, and its form can be used in architectural aspects, such as angle steel; The cross-section is a circular circular object with the greatest lateral bearing force, and similar forms of building materials can be found everywhere, such as TV towers, telephone poles, etc.

In the process of observation, experimentation and analysis, I gradually explained and revealed the mystery of the cone-shaped trunk, increased my knowledge, and applied the knowledge I learned in connection with practice, which not only consolidated the knowledge I learned, but also improved my interest in learning, and I also learned the methods of scientific observation and analysis.

We love science, and there are a lot of them.