The pencil lead heater dripped a few drops of melted wax on the pencil lead. After the wax cools, connect both ends of the pencil lead to the battery.
After a while, you will see that the wax on the pencil lead has melted again. This shows that when the current passes through the pencil lead, it is converted into heat energy to melt the wax.
Generally speaking, after current passes through a conductor, the conductor will heat up. We call this phenomenon the thermal effect of current. The greater the resistance of the conductor, the stronger the thermal effect.
For example, the commonly used copper-aluminum wire has a small resistance and the heat generated after being electrified is very weak. The wires of the electric furnace are different. It is a kind of resistance wire with large resistance, which can generate a lot of heat after being electrified.
If pencil lead is connected with a stable and continuous low-voltage power supply, pencil lead can heat for a long time. Putting it in a fish tank can heat the water, keep it at a certain temperature, and let the fish spend the winter comfortably.
2. Popular science pictures are simple and beautiful.
Basic introduction
The simple explanation of science fiction is fantasy based on science. There are different opinions about the definition of science fiction, and the scales vary greatly. In the broadest sense, as long as the story contains surreal factors, it can be counted as science fiction. Orthodox sci-fi fans hold stricter standards and believe that at least one sci-fi factor-science and fantasy are indispensable. If there is no scientific basis, it can only be classified as fantasy, magic or surreal works; On the contrary, if fantasy is not paid, it is just a scientific and realistic story. Nabokov, a famous Russian novelist, has an intriguing famous saying: "Science cannot be separated from fantasy, and art cannot be separated from reality", which is perhaps the best portrayal of science fiction.
Science fiction painting is the content of scientific fantasy, which has certain scientific basis. It is a painting form displayed on the screen by painting. Specifically, on the basis of our understanding of scientific knowledge, through scientific imagination and the use of painting language, we creatively express our reverie about the universe, future human social life, social development, science and technology and produce paintings. Science fiction painting is an art form that truly reflects children's pursuit of a better life. Children's science fiction painting is a painting that children creatively express their reverie about future human life, social development and cosmic science and technology through scientific imagination on the basis of the knowledge and experience they have mastered. Children's science fiction painting is an art form that truly embodies children's childlike innocence. It reflects the children's most direct, simple and profound feelings about the world around them in the face of the future.
Correlation difference
Science fiction painting is different from what we usually say about children's paintings. Often based on age. All paintings of underage children are collectively called children's paintings. Children's painting is a painting that children observe, experience and remember in real life.
There are also many children's bold fantasies, and there are often beautiful fairy tales in these paintings with longing for a better life. For example, children's paintings such as "Looking for Sister Chang 'e on the Moon" are just legends, not science fiction painting. Moreover, children often paint the little sister's facial features and the sun as old people to draw crescent moons, which belong to fairy tales, not science fiction painting.
Science fiction painting is not a fantasy in the general sense. It is a fantasy work with the concept of the times and a certain forward-looking and scientific content. We must use scientific knowledge and scientific laws to fantasize. "Today's fantasy will become tomorrow's reality." As for how many days and years it takes to realize this fantasy, it may be long or short. ...
Science fiction painting is different from popular science painting.
"Popular science painting" is to show some scientific knowledge in the form of painting, with pictures and texts, and intuitively popularize and publicize scientific knowledge, so general popular science painting is more realistic, while science fiction painting requires freehand brushwork. Science fiction painting's role is limited to popular science propaganda, but he strives to be full of exploration spirit and imagination, create new things and build a new life and a new world.
Positive meaning
Science fiction painting is a good way to guide students to contact, explore and love science, and it is also a good way to cultivate young students' imagination and thinking ability. Children's science fantasy painting embodies children's imagination and prospect of scientific development, and establishes the idea of loving science and the Chinese nation. At the same time, it is of great significance to cultivate children's scientific imagination, innovative consciousness and inquiry learning ability.
How to draw well
It is not difficult to draw science fiction painting well. Usually pay attention to reading more science fiction books,
Participate in more scientific lectures and scientific and technological innovation activities, and combine sci-fi painting with inventions, scientific papers, process design and other technologies. We should also pay attention to observing and collecting new things and information around us, and pay attention to astronomy, geology, ocean, environment, bioengineering, information engineering, nanotechnology, genetic engineering and so on. Further imagine, conceive and create known knowledge and information. In addition, students can turn some small things they encounter in their study and life into convenient, reasonable, comfortable and convenient things, and they can also show them by painting. As long as there is an organic combination of bold and rich scientific imagination and individual painting forms, it is a good work.
standard
The award criteria can be summarized as two words: artistic and scientific.
Award criteria can be summarized as two good: good content and good form.
Before painting science fiction painting, we should collect and master relevant information about space and environmental protection, and broaden our horizons, so as to draw works with entities and whimsy. You can also give some tips: for example, because there are too many people on earth, build a house on the seabed and draw a picture of an underwater home. If you show pictures and videos, you can also look up information on aerospace and environmental protection before class. When you have relevant materials, you will propose good solutions to the problems in life, express your meaning through sketches, and finally create your imagination until it is completed.
Appropriate skill guidance. For example, the painting is relatively large, the composition is full, the image is vivid, and the lines and colors are smooth. It can be carried out in three steps: imagination-sketch-drawing. We can use our peers' good homework as a guide, and we can also learn from painters' works. There are various methods.
3. Small common sense of science and technology
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 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 move on.
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 sea itself is around us.
4.50 Less scientific knowledge
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.
2. 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.
3. 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.
How high is the blue sky? "Blue sky" is actually the earth's atmosphere. The atmosphere surrounds the earth's air and is divided into five layers according to the air density, with a total thickness of 2000-3000 kilometers.
But most of the air is concentrated below 15 km from the ground, and the higher the air, the thinner it is. How thick the atmosphere is, how high the blue sky should be.
5. Why are there no stars in the daytime? Because part of the sunlight is scattered by the gas and dust in the atmosphere during the day, the sky is very bright and the light radiated by the sun is so strong that we can't see the stars. 6. What celestial bodies are there in the solar system? There are nine planets in the solar system.
They are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. In addition, there are many asteroids, comets and meteors in the solar system, and there are 2958 officially numbered asteroids.
The most famous comet is Halley's comet. 7. Why does it thunder? This is a natural phenomenon that negative electricity meets positive electricity.
When it rains, some clouds in the sky are positively charged and some are negatively charged. When two clouds meet, they will discharge, emit bright and bright lightning, and at the same time release a lot of heat, which will make the surrounding air heated, expand and make a loud noise. This is thunder. 8. Why can an airplane fly into the sky? This plane has two wings, like those of a bird. It has a propeller.
The wing can generate lift and lift the plane into the air; Propeller can produce the ability to push the plane forward. Therefore, the plane can fly into the sky like a bird.
33. For a 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.
9. Before the boiling water rang, the bubbles in the water rose and vibrated up and down due to convection. Most bubbles burst under the pressure of water, and their bursting sound and vibration sound together with the container produce * * * sound, so the sound is very loud. After water boils, it is isothermal up and down, and the bubble volume increases. Under the action of buoyancy, it will burst as soon as it reaches the water surface, so the noise is relatively small.
10. Fire-water incompatible substances must reach the ignition point when burning. Because of the large specific heat of water, water can absorb a lot of heat when it comes into contact with fire, thus reducing the temperature of ignition materials; At the same time, the vaporized water vapor surrounds the burning object, making it impossible for the object to contact with air. Without air, combustion cannot be carried out. 1 1. Sit on the ground and walk for 80,000 days. Because the radius of the earth is 6370 kilometers, every time the earth makes a circle, the distance that objects on its surface "walk" is about 40003.6 kilometers, about 80000 miles.
This is a poem sung by * *, which also scientifically reveals the relationship between motion and stillness-motion is absolute, and stillness is always relative to the reference object. 12. According to the principle of lever balance, if the power arm is a fraction of the resistance arm, then the power is several times the resistance.
If the weight of the arm is very large, it is entirely possible to "dial one or two kilograms." 13. When the distance between molecules is large (more than several hundred angstroms), the attraction between molecules is very small, almost zero, so it is difficult to reassemble a broken mirror.
14. If the directions of the components are the same, the resultant force is equal to the sum of the components. 15. Tofu can't be hung with hemp rope. When the pressure is constant, if the stress area is small, the pressure will be great.
16. True gold is not afraid of fire, and truth is not afraid of argument. Judging from the melting point of gold, although it is not the highest, it is 1068℃, while the temperature of general flame is about 800℃. Because the temperature of the flame is lower than the melting point of gold, gold cannot be melted. 17. With a long whistle, people in the valley should give a long whistle. After many reflections, the sound can form a loud echo, which lasts for a long time. As if the mountains were shouting and the valleys were echoing.
18. Looking at the sky from the well, you can see very little. Because light travels along a straight line, from the knowledge of geometric drawing, the frog's field of vision will be very small. 19. It can be seen from the pressure formula that when the pressure is constant, the smaller the stress area, the greater the pressure.
People will feel very uncomfortable sitting on such a blanket. 20. Good years are bright. Because snow is a bad conductor of heat, when it covers crops, it can well prevent heat conduction and air convection, so it can play a role in heat preservation.
2 1. It is cold before frost and cold after snow. In the late autumn night, the temperature near the ground suddenly turns cold (the temperature is below 0℃), and the water vapor in the air condenses into small ice crystals and adheres to the ground to form frost, so it feels "cold before frost". When snow melts, it needs to absorb heat to reduce the temperature of the air, so we have the feeling of "cold after snow".
22. Eggs touch stones-overreached eggs touch stones. Although the force is the same, the pressure that each object can bear is certain. If this limit is exceeded, the object may be damaged. Eggs can withstand less pressure, so they will break.
23. Before the jade is polished, the surface is uneven and the light is diffuse. After the jade is polished, the surface is smooth and the light is mirrored. 24. Fans have cool air, and fans in summer are better than fans in winter and summer.
5. Science fiction painting about science
Science fiction painting is a good way to guide students to contact, explore and love science, and it is also a good way to cultivate young students' imagination and thinking ability. Children's science fantasy painting embodies children's imagination and prospect of scientific development, and establishes the idea of loving science and the Chinese nation.
At the same time, it is of great significance to cultivate children's scientific imagination, innovative consciousness and inquiry learning ability. 1 First of all, based on life, the content conforms to the reality of life, with authenticity, and the technology comes from life; 2. The theme has a certain scientific basis and can be applied to correct scientific principles. There is no superstitious content or idealistic content. Your idea should be based on an accurate grasp of scientific principles that may be realized through the development of technology and science in the future; 3. Teachers should be forward-looking. It is not necessarily the science and technology we know at present, but the possible development direction in the future: allowing bold imagination of future scientific development requires teachers to constantly learn and absorb new knowledge about the future development direction of science and technology, learn knowledge through multiple channels, and understand all fields of social science and learning methods-Internet, books and newspapers, magazines "We Love Science" and "Little Edison".
4. How do teachers guide students-how to express their thoughts accurately and appropriately by using scientific principles? The difficulties lie in: students lack knowledge, narrow knowledge and lack of understanding of scientific principles. The scientific principles used by teachers as knowledge consultants and assistants are close to the current situation of students' knowledge, so don't excessively pursue the accuracy and rigor of knowledge. Creativity and technology should be compatible with their knowledge level and their mastery of science and technology.
6. Small technology products
Come on, teach you something useful.
The simplest: make a pen container! ! Do you have any unused glass cups at home? Or a broken teacup, try it, as long as it is heavy enough to hold a pen. Find a beautiful cloth, or colored paper, and make a dress for the cup.
Kraft paper is also good. Wrap it in a cup, measure it well, cut a suitable piece, and leave a margin of about one centimeter at the joint. Find some glue, paste, all-purpose glue and stick the coat on the cup.
Chewed gum will do. Chewed gum should be pulled down a little. It is important to stick the edges and seams tightly. That's about it. Trim the untidy place, stick an ornament casually, and write a few words with colored pens, and it's done.
No decorations? Find a pictorial, cut some beautiful ribbons that fall off your clothes, or draw them directly. Well, your work is over.
If you are really interested in handcrafting, or need anything else, just leave me a message.
7. Art tips
Art usually refers to painting, sculpture, arts and crafts, architectural art, etc. They are carried out in space, expressed and appealed to human vision.
When this name was first used in Europe in the 17th century, it generally referred to painting, sculpture, literature, music and other things with aesthetic significance. When I began to use this word in general around the May 4th Movement, it also had the meaning equivalent to the whole art. ..
For example, when Lu Xun explained the word "art" in 19 13, he wrote: "art is a word ... translated from English love. People who love clouds are originally from Greece, and their friendship is art.
Soon after, China translated the word "love" with the word "art", and the word "art" became the name specifically referring to visual arts such as painting. Modeling expression means: the skills and means to create artistic images in plastic arts.
Such as painting with the help of color, light and shade, lines, anatomy and perspective; Sculpture depends on volume and structure. These techniques and means, through long-term artistic practice, have formed the unique and special artistic language of these plastic arts, which determines the different expression rules of these arts and is related to the success or failure of the plastic arts image and the appeal of artistic works.
The artist's constant exploration and improvement of the regularity of modeling expression means is a necessary condition for artistic creation to express new life content and meet people's developing aesthetic hobbies. The golden section is also called Huang Jinlv and the golden ratio.
On a line segment, the line segment is divided into long segments and short segments according to the optimal length-width ratio, or the optimal ratio of long sides to short sides of a rectangle is formed according to the optimal length-width ratio, that is, the golden section. Terms of two-dimensional painting.
Refers to the plane space composed of length (left and right) and height (up and down). In painting, in order to truly reproduce the image, we often use perspective, shading and other modeling methods to create the profound feeling and three-dimensional effect of the image on the plane of the second space, that is, to create the illusion of the three-dimensional space of natural objects with the second space.
Some paintings, such as decorative paintings and pattern paintings, do not require strong depth effect, but deliberately pursue the plane meaning of the second space in order to obtain artistic expression. Stereographic terminology.
Refers to the three-dimensional space composed of length (left and right), height (up and down) and depth (depth). In painting, in order to truly reproduce the image, it is necessary to show the three-dimensional sense and depth on the plane.
Texture painting, sculpture and other plastic arts show the characteristics of various objects in their works through different expression techniques, such as silk, skin, water, stone and other different qualitative characteristics, giving people a sense of reality and beauty. With the help of light and shade, color, lines and other modeling factors, the sense of quantity expresses the feeling of the weight, thickness, size and quantity of an object.
Such as the solemnity of rocks and the lightness of wind and smoke. All realistic objects in painting are required to convey their unique weight and realism.
Using the comparative relationship of quantity, we can produce diverse and unified effects. In painting, according to the principles of geometric perspective and air perspective, the sense of space describes the relationship between objects such as distance, level and interpenetration, thus conveying a profound three-dimensional sense in plane painting.
Terms of volume painting. Refers to the visual objects displayed on the painting plane can give people a three-dimensional sense of occupying three-dimensional space.
In painting, any visible object is determined by the structure of the object itself, which is composed of blocks with different directions and angles. Therefore, it is necessary to grasp the structural characteristics of the object to be painted and analyze its proper relationship in painting in order to achieve a sense of volume.
Theoretical terms of perspective painting. The word "perspective" comes from the Latin word "perspclre".
At first, perspective is to look at the scenery through a transparent plane, and accurately draw the scenery on this plane, that is, to form a perspective view of the scenery. Later, according to certain principles, the science of expressing the spatial position, outline and projection of an object with lines is called perspective.
Terms of light and dark painting. Refers to the brightness change of light, backlight and reflective parts of objects in painting and the expression method of this change.
An object has three bright and dark states under illumination, which are called three major surfaces, namely, bright surface, middle surface and dark surface. The light and color of the three major surfaces are generally dark in the middle.
The light and shade of the three major surfaces are generally manifested in five basic levels, namely, five tones: ① the bright surface is always illuminated; (2) Gray surface-middle surface, half bright and half dark; (3) the dividing line between the bright part and the dark part; (4) a backlight part on the dark side; ⑤ Reflect the dark and bright parts of a single surface affected by ambient reflection. It has always been the basic method of square painting to describe objects according to the level of light and shade.
During the Renaissance, vasari once said in "Biography of Artists": "When painting, after drawing the outline, use shades to roughly distinguish the light and shade, and then carefully display the light and shade in a single room, so does the bright part." Rembrandt is a master of shadow techniques among European painters.
Terms of contour plastic arts. Refers to the edge line that defines the range of performance objects.
In painting and sculpture, whether the outline is correct is regarded as the key to the success or failure of the work. Terminology of composition and plastic arts.
Refers to the structural configuration method of artistic images in works. It is an important means for plastic arts to express the ideological content of works and gain artistic appeal.
One of the important factors of color painting. It is a complex phenomenon that various objects absorb and reflect light to varying degrees and act on people's audience.
Due to the different textures of objects, the absorption and reflection of various colors of light are different, so everything in the world has formed ever-changing colors. The qualitative appearance that tonal colors can present.
Different colors in nature are infinitely rich, such as purplish red, silver gray and orange yellow. Chromaticity refers to the inherent lightness of the color itself.
For example, among the seven basic colors, purple * * * is the darkest and yellow * * * is the brightest. Tone is also called tone.
Under the irradiation of light source color with certain hue and lightness, the surface of the object is shrouded in a unified color tendency and color atmosphere, which is hue. Colors have no attributes.
Colors are basically divided into warm colors (also called hot colors) and cool colors (also called cool colors). Red, orange and yellow are warm colors, giving people a warm, warm and outgoing feeling.