As for perpetual motion machines, you should have seen something about perpetual motion machines on the Internet! Most of them are perpetual motion machines made of magnets. Let me explain the principle of magnetic perpetual motion machine.
Hard magnets (permanent magnets) and soft magnets, whether natural or artificial, will lose their magnetism in any shape. Moreover, they will be weakened by the influence of the earth's magnetic field on the earth, and will also be weakened when they encounter high temperature and impact.
The rotation and translation of the perpetual motion machine are formed by the mutual repulsion of magnets, and the electrons in the electric field generated by magnets move in disorder. Under the mutual repulsion of magnets, electrons cancel each other out under the magnetic effect, which also consumes magnetism. Coupled with the earth's magnetic field and the magnetic force consumed by high temperature, the magnetic perpetual motion machine will always stop. So at this rate, it is impossible to build a magnetic perpetual motion machine, because it always consumes energy. The "magnetic perpetual motion machine" we saw on the Internet does not violate the law of conservation of energy, but it is not a perpetual motion machine.
There is also a small Marta on the market, which is also made by using the principle of magnetic repulsion. These are a large part of the reasons for using electromagnets.
It is impossible to build a perpetual motion machine because we have violated the law of conservation of energy. We can't expect the birth of perpetual motion machine, but we can only use the' endless energy' around us (such as solar energy, wind energy, hydropower, plant energy ...) to transform the world.
Friction three brothers Friction three brothers refer to static friction, sliding friction and rolling friction, all of which are members of the friction family.
Speaking of friction, everyone must be familiar with it, because friction is a common phenomenon in our lives, and we deal with it all the time. We walk, eat and wash clothes by friction; The operation of all kinds of vehicles depends on friction, and the operation of machines is also inseparable from friction; Even building a house is inseparable from friction.
What would the world be like without friction? I can't imagine. It can be said that friction is our inseparable good friend. However, on many occasions, the three brothers play an "unwelcome" role.
In modern cars, 20% of the power is used to overcome friction; The friction loss of piston engine in aircraft accounts for 10% of power, and even the most advanced turbojet engine needs to overcome the friction loss of 2%. There are thousands of cars and planes in the world, so it's a pity how much fuel is wasted every year.
But more seriously, friction will also cause the wear and tear of machine parts. It is reported that the loss of Britain in this respect exceeds $2 billion every year. Friction not only causes wear, but also causes overheating of aviation and spacecraft, which is another difficult problem encountered by modern science and technology.
When the plane lands, the gate valve and the brake wheel will rub to produce red heat, which will make the brake material soft and deteriorate. Expensive brake shoes and wheels are usually scrapped after only a few uses.
When the spacecraft returns to the ground, the whole ship will turn into a red fireball due to the friction between the hull flying at high speed and the air. In order to protect the astronauts and all kinds of instruments and equipment in the spacecraft, people have to pay a high price, make the hull with special alloy with high temperature resistance, and install high temperature resistant materials outside.
In order to control friction and make the three brothers of friction better serve mankind, people have been carrying out arduous research and exploration. As early as15th century, Leonardo da Vinci began to study friction. In the 17 and 18 centuries, there was an upsurge of friction research in France, and Coulomb completed the concave-convex theory of friction according to Leonardo da Vinci's ideas. /kloc-in the first half of the 0/8th century, someone founded the molecular theory. After entering the 20th century, the adhesion theory reappeared.
It can be said that the debate about the cause of friction continues. Concave-convex theory, molecular theory and adhesion theory are all well-founded. How to satisfactorily explain the causes of friction has always been a very active research topic.
Why didn't the inflatable hole of basketball leak before? I went to play basketball and found that the ball was flat, so I ran home to inflate it. At this moment, I found a problem!
I found that the hole for pumping basketball was not blocked. At that time, I wondered why there was no plug If you inflate the ball, not all the air leaks out! I studied basketball repeatedly with doubts. I put my ear on the inflatable hole, listen carefully to the sound of air leakage, and feel it with my hands. I really can't figure out how it didn't leak.
With this question, I asked my parents. They all shook their heads and said they didn't know Curiosity drove me to find out the truth, and I couldn't wait to open the encyclopedia. After a careful look, I didn't find out why the inflatable hole of basketball didn't leak. I turned on the computer, eager to find the answer. After half an hour, many things will happen. I finally know why.
In fact, because its eyes are a kind of rubber pad, when it is inflated with the ball needle, the rubber pad will be washed away by the huge pressure of the air pump, and when the air pump is pulled out, the gas in the ball will give the rubber pad an unexpected force and make the rubber pad return to the closed state. Therefore, basketball looks airtight at first sight, unless its rubber pad is worn out and can't play a sealing role.
I see. I'm so happy! ! ! ! I learned new knowledge today!
Electromagnetic-driven "internal combustion engine" is widely used in today's industrial fields and vehicles, which provides us with great convenience, but with its application, many disadvantages are increasingly exposed. Traditional internal combustion engines need to "drink oil". While consuming a lot of fossil fuels, their exhaust gas will inevitably transform the environment until it is destroyed, such as "urban heat island effect" and "global greenhouse effect".
I think if the traditional internal combustion engine has electromagnetic intervention, its vitality will continue to flourish. The specific design idea is simply: a coil can be modified on the piston of internal combustion engine, and an armature can be inserted into the coil, and the piston and armature are still a reciprocating whole; In addition, a coil (in which an armature is still inserted) is installed at the spark plug position at the top of the cylinder of the internal combustion engine, which is fixed as a whole with the internal combustion engine. In this way, alternating current with a certain frequency is respectively connected to the two coils (the two coils and the power supply device are independent of each other), and the polarities of the armatures in the two coils are changed by adjusting the frequency of alternating current, so that the two armatures repel each other with the same name in the first half of alternating current, and attract each other with the same name in the second half. The piston is driven by the process of repulsion and attraction, and the crankshaft turns the reciprocating motion of the piston into rotary motion through the connecting rod, thus realizing the conversion from electric energy to mechanical energy, and the frequency of alternating current can be conveniently changed by adjusting the electronic circuit. ?
(Note: From the principle of the above device, it is not difficult to see that the tightness of the system composed of piston and cylinder can be ignored. In the design, the cylinder can be abandoned and replaced by a track for the piston to slide back and forth, which can not only simplify the industrial production process, but also greatly reduce the energy lost by friction between piston and cylinder and improve the efficiency of the machine. )