Do you believe that fish can talk? This is an intriguing thing. I wonder if fish can talk.

My family bought two small goldfish, one is all black, and the black one is called Lele, because it is very happy. A red and white name is Xinxin, because it knows how to appreciate. Isn't it fun? They live in a fish tank, which is "unusual". There are mountains, flowers, trees, shells and colored stones. Isn't it beautiful? Let's take a look together!

At about five o'clock in the morning on September 23rd, I was about to breast-feed. I saw such a phenomenon. I spilled fish food into the fish tank, but Lele ate a little and stopped eating.

At 5 pm on September 23rd, I saw the shell in the fish tank turned upside down. Xiao Xin saw it, as if she thought-this little shell was going to die. She swam quickly and reached it with her head. After three or four minutes, I can't reach it. She swam to Lele, swept Lele with her tail, and then touched her head. Lele and Xinxin are together.

Through two observations, I know that human beings have their own expressions and communication languages, and animals also have their own kingdom expressions and communication. This also tells us that if you don't unite, then you will have nothing, and the friendship between friends is really great. At the same time, you should observe more and find more, but you can't hurt small animals just because you are doing experiments on them, because animals are friends of human beings.

Why don't ants get lost?

Ants, I believe everyone is familiar with them. Then who can really understand ants? Why don't ants get lost?

With this question, I consulted some books. According to the book, ants leave some smells along the way after starting from the nest to their destination, and then return to the nest. Touch each other with tentacles and notify other ants. Scientists have done an experiment on this problem. Scientists first identify an ant and vigorously clean up the place where he reaches his destination along the way. When the ant came back, it suddenly stopped at the place where the smell was wiped off. Looking for something while walking in circles. People come to the conclusion that ants can tell their directions by their sense of smell.

In order to confirm this conclusion, I did an experiment. I first prepared a twig about 10 cm, and put the bait-small candy on one end of the twig. I put this device near an ant nest. After a while, an ant came out to explore the road. After I led him to the stick, he went to the place where the sugar was put, as if he were smelling it. I took this opportunity to cut off the broken part of the stick by one centimeter. When the ant came back, it turned left and right where it was cut off, but it couldn't find its way home.

After a while, I repeated the above experiment, and the ants still didn't find their way home.

Through these two experiments, I finally know the secret of ants not getting lost. It turns out that ants can tell the direction by smell.

Knowing the secret of ants, I was thinking: Can you make an ant alarm? When an ant approaches the alarm, the alarm can "smell" the ant and then chirp to let us know that the ant has gone to the cupboard or other places.

"Students, have you brought all the eggshells?" The teacher asked. "I brought it!" We answered with one voice.

In today's science class, the teacher asked us to bring eggshells. What do you do with eggshells? Are you a tumbler? We are all curious.

"Today, we are going to do a small experiment with these two and a half eggshells. Before you do it, please guess, I use this pencil to stab the eggshell vertically downward. Is the eggshell with the mouth up broken first or the eggshell with the mouth down broken first? " "Of course, the mouth is first!" Most students scrambled to answer. "Mouth up first!" My deskmate is determined to go against everyone. The teacher smiled and said, "Well, let's do an experiment to see whose answer is correct."

The teacher called a classmate to the podium and asked him to point the pencil up at the eggshell. At the teacher's command, the students let go of their hands, and the pencil poked the eggshell, but it didn't break. The teacher asked him to try several times, and when the pencil stabbed for the third time, it finally broke the eggshell. Then, the teacher asked him to poke the eggshell with a pencil. "Once, twice, three times ..." Let's count together; But that half eggshell is like wearing armor, and it won't break after being stabbed more than ten times.

"Yes! I guessed right! " The deskmate danced with joy. Although we are not convinced, after many experiments, we found that the same two eggshells, tied vertically with a pencil, are indeed easier to break with their mouths up. The teacher told us that this is because the stress on the eggshell with the mouth up is concentrated, while the stress on the eggshell with the mouth down is scattered, so it is stronger. No wonder all the workers and uncles on the construction site are wearing face-down safety helmets. That's the truth!

Every Sunday, I always finish the task of shoeshine given to me by my mother. Tell you, this is the source of my pocket money for a week! After getting the leather shoes covered with dust, I first wipe off the dust on the vamp, then apply shoe polish and wipe them carefully, and the leather shoes will become bright and beautiful. But why is this?

I found two pairs of old and new leather shoes of the same brand and style for comparative observation. I first touched the uppers of two pairs of leather shoes and found that the surface of the new shoes was much smoother than the old ones. Old leather shoes are coated with shoe polish. After careful polishing, it shines a lot, but it is still not as good as new leather shoes. Is there a relationship between the brightness of leather shoes and the smoothness of uppers?

I brought a pair of old leather shoes that were not polished, and the uppers were uneven under the magnifying glass. Then, I circled two rough areas A and B on the leather shoes. Carefully wipe area A with shoe polish, and area B without shoe polish as a blank control. I found that the surface of area A is obviously smoother after wiping, and it is more shiny than area B when placed in the sun. Why is there such a big difference between them?

I remember the teacher once said in science class that the wall surface of the theater is uneven, so that most of the sounds can be absorbed and the audience will not be disturbed by the echo. Similarly, light will be reflected on the surface of any object. If the plane is uneven, light will scatter in all directions. If this plane is smooth, then we can see the reflected light in a certain direction.

The surface of leather shoes is not absolutely smooth. If it is an old leather shoe, its surface is of course more uneven and can't reflect light in a certain direction, so it looks dull. There are some small particles in shoe polish, which can just be filled into the pits on the surface of leather shoes when shining shoes. If you wipe it with a cloth again, the shoe polish will be more uniform, the surface of leather shoes will become smooth and flat, and the reflective ability will be strengthened.

Through the experiment, I finally know the secret of shoes getting brighter and brighter!

1. Small color projection needle

A magnetic needle is a compass. Compass is one of the four great inventions in China. In the present physics teaching, a small magnetic needle can be used to judge the direction of the magnetic field. However, it is very inconvenient to use magnetic needles sold in the market or investigated and dialed by higher authorities. When the teacher is doing the demonstration experiment of magnetic field direction, the students can't see clearly below, so the teacher has to take the instruments down and show them to the students one by one, which is very time-consuming. What shall we do? After trying their best, the students finally made a simple color projection magnetic needle, which can be used as a compass and projected on the projector, so that the whole class can see the direction of the magnetic field, which provides great convenience for teaching experiments. 、

Simple projection needle has simple structure and common materials. It is made of card pins, pins, plexiglass strips and transparent projection film materials. The manufacturing method is: put two steel needles on the two steel needles respectively, and pay attention to the balance of the two steel needles. Then cut the transparent film into sharp long pieces, stick it on the steel needle with 502, one at each end, pay attention to symmetry, and then paint it red and green respectively. In this way, the upper part of the magnetic needle is completed. Saw the plexiglass strip into a block, then grind it into a round base of the magnetic needle, and iron it in the middle of the round plexiglass. Please note that the pin should be perpendicular to the base. The inner groove of the small snap button is used as the bearing support hole for rotation. Put the bearing on the needle tip, so that the magnetic needle will rotate on the needle tip. The last one is to wipe the S pole of the bar magnet from the middle of the magnetic needle to the green side, and magnetize the small magnetic needle, that is, the N pole. So that the small magnetic needle is magnetized.

Put the self-made small magnetic needle on the projector, and you can see the direction of each point of the magnetic field at a glance from the curtain.

2. Why can clothes keep people warm?

First of all, you should ask yourself: Can clothes really keep people warm?

You know, it's not leather that keeps people warm. On the contrary, people keep fur coats warm. Right? You know a fur coat is not a stove. "What?" You will ask. "Is that man a stove?" Yes, man is a stove! We already know the food we eat-this is chopping wood, which burns in our bodies. At this time, we didn't see any sparks. We say it is burning only because we feel that there is heat in our body.

This heat needs to be protected. In order to prevent the heat in the house from spreading to the street, we built thick walls, installed double windows in winter, and wrapped blankets on the doors. We wear clothes for the same reason. Instead of letting our body's heat radiate to the indoor air or the street, we keep our clothes warm, which keeps our heat around our bodies. Of course, our clothes also give off heat, but it is much slower than our bodies.

3.[ Scientific Papers] Energy-saving street lamps

The Chinese nation has a fine tradition of thrift, and the people of China have maintained this good style since ancient times. This feature is also reflected in productive labor and daily life. We should always try our best to do everything well in the most economical way. It is because of this good idea that we know how to save energy. The energy problem is of extraordinary significance to a populous country like China. With the development of economy and the large-scale exploitation of resources, the problem of energy shortage has become more prominent, which has greatly affected the modernization of China. Up to now, our country still advocates thrift. In the major construction of Olympic venues, the state put forward the slogan of "running the Olympic Games frugally" according to the actual needs. On the 55th anniversary of the National Day this year, the slogan "Save the National Day" was put forward one after another. Our country is proceeding from the overall situation and achieving the diligent style from the aspect of energy conservation. Saving energy can reduce expenses, promote economic growth and protect the natural environment, which is also a prerequisite for taking the road of "sustainable development" and for our future generations.

At night in the city, there are dense and neat street lamps on both sides of the road, which looks like a dragon flying. Although this is a beautiful scenery, many times the lights of these street lamps are wasted because the road is empty for a large part of the time, especially in areas with underdeveloped economy and transportation. The huge waste of power resources has brought negative effects on the economy of these areas, which is not beneficial, but harmful. Then, is there an automatic control device that is convenient for pedestrians and vehicles to pass at night and saves energy?

Saving energy is actually to reduce energy loss as much as possible. On remote roads, the traffic flow is very small, and turning on street lamps for a long time, whether there are cars, no cars, pedestrians or no pedestrians, will cause great waste of energy. You shouldn't turn on all the road lights even if a car passes by. You should only turn on the street lights within the effective range of the vehicle, otherwise it will cause great losses! So do pedestrians walking on the road. Only turn on the street lamps within the corresponding range for pedestrians to meet the lighting needs. This problem can be compared with the common voice switch now. As long as someone walks in the stairwell and makes a sound, the light will light up when the vibration generated by the sound is transmitted to the voice control switch, and the light will only light up within the pedestrian's walking range and will not light up for a long time. From this, we can know that when vehicles and pedestrians pass on the expressway, don't they exert pressure on the pavement? If there is an inductor that can automatically control the switch under the pressure and control the lights on and off within the corresponding range, the purpose of energy saving will be achieved.

Then this sensor can not be controlled by air vibration generated by sound, but by road vibration generated by the impact and pressure of vehicles and pedestrians on the road. These two kinds of vibrations are different, otherwise it is a mistake, which may be the barking of animals. The noise outside the road will turn on the lights, and it will also fail to achieve the purpose of energy saving. If the noise from vehicles and pedestrians is very small, the lights will not light up? That's useless. It doesn't work at all. The driving of cars and the walking of pedestrians will naturally produce impact and pressure on the ground, which will make the road surface vibrate, so that the road surface vibration can be used to control the opening and closing of street lamps. If there is such a device, it can be installed in the light box of a street lamp, and each device is connected to the road surface with a metal bar. When the road surface is impacted and vibrated by pressure, the corresponding street lamps will light up, and the lights will light up where there are vehicles or pedestrians, and the vibration will stop, and the lights will automatically go out within a certain time limit. This device uses vibration and pressure to control street lamps, which can play a very good role in energy saving. Of course, in order to reduce the number of installed devices, such a device can control multiple street lamps, and multiple devices are connected in parallel in a circuit, that is, one device is installed at intervals, and then these devices are connected to the corresponding street lamps through wires. We might as well name it "vibration sensor" first. Let's first look at the working principle of the "vibration sensor": First, the metal bar is used to sense whether the road surface vibrates. When a car or pedestrian passes a certain road section and exerts pressure on the road surface to generate vibration, the metal bar transmits the vibration to the "vibration sensor", which is stimulated by the vibration and commands several street lamps it controls to turn on the switch. Vehicles and pedestrians continue to pass the next road section, and the "vibration sensor" of the next road section is also stimulated by vibration, which also lights up the corresponding street lamps, and so on. At the same time, the "vibration sensor" on the road section after vehicles and pedestrians passed by turned off the switch because it did not continue to receive the vibration information transmitted to it by the metal strip, so that the corresponding street lamps did not continue to emit light. But this kind of "vibration sensor" requires high sensitivity and can also identify the vibration source. For example, under special circumstances, lightning weather or high-decibel noise generated by factories will make the air vibrate violently, and it will also be transmitted to the "vibration sensor" through metal bars. The "vibration sensor" mistakenly thinks that the vibration comes from the road surface, which makes the street lamp shine. Therefore, we need to use science and technology to study and develop a novel. Huh? Don't say that. Apricot ζ ao is out of danger? Visit? Blow molding? So the sheath is charming? Hey? Scratches? Blow?

Well, as long as this "vibration sensor" is installed on the road with street lights, it doesn't need a lot of manpower to control the power supply, and all the work will be automatically controlled by the machine. We can imagine that there are cars or pedestrians passing by on the road, and the scene of street lamps flashing and going out for the second time is dazzling and overwhelming. Isn't evening a unique and beautiful scenery? At the same time of convenient transportation, the biggest advantage is that it saves energy greatly.

This kind of "vibration sensor" is designed to save energy. I hope this device can be applied to practice and play a great role. While developing the economy, we must not ignore the importance of energy conservation, save energy and take the road of sustainable development, which has become the common sense of mankind.