- Guessing the popular science of the ten-year-old Turing: special relativity.
In the scientific community, there is a British scientist named Alan Turing, who is known as the father of computer science in the world. When he was ten years old, in order to popularize the theory of relativity to his mother, he wrote a popular science article on special relativity. This story not only shows Turing's love and talent for science, but also shows us his talent for physics.
The article did not circulate. Let's guess (at least we didn't) how a ten-year-old Turing explained the basic concepts of special relativity in simple, understandable language.
First of all, in order to better understand the special theory of relativity, Turing first introduced the concept of Newtonian mechanics. He explained the notion in Newtonian mechanics that time and space are absolute, i.e. they do not change depending on the observer's state of motion (rest or motion). However, Newtonian mechanics encountered difficulties in describing some phenomena of high-speed motion. To solve these problems, Einstein proposed the special theory of relativity.
Turing introduced an important concept in the special theory of relativity—space-time. He explained that time and space are indivisible and unified wholes, and they make up space-time. When the speed of motion of an object is close to the speed of light, its motion effect will change significantly, resulting in "shrinking rulers and slow clocks". When the object is moving much lower than the speed of light, the motion effect is negligible and completely negligible.
"Slow Clock" may be the subject of ten-year-old Alan Turing's theory of relativity.
In this article, it is possible that Alan Turing first introduced his mother to the two basic principles of special relativity in plain language. The principle of invariance of the speed of light is that the speed of light is the same for reference frames regardless of whether they are stationary or moving at a uniform speed. The principle of relativity is that the laws of nature, that is, the laws have nothing to do with the choice of inertial frame of reference, whether you are on the ground or on a smoothly running train, how high and how far you can jump are constant, and their presentation and expression are the same.
"Ruler shrinkage and slow clock" are relatively static, and they are shown by comparison. How do you compare?The first step is to establish a common point of reference.
Just like a sports competition, there must be a fair and impartial starting point;There should also be an end point for comparing the results, which is used as a starting point for judgment. Albert Einstein gave a good example in his article "The Relativity of Simultaneity". Two lightning bolts that hit the moving train and the track at the same time, instantly striking four electric shock points, two at the front and rear of the train;The other pair is on the rails, making up two pairs of distances. Instantaneously, since there is no relative motion-displacement between the two frames of reference, they are equal.
As soon as the moment passes, the relative motion is immediately revealed. In the space of movement, there are two different kinds of motion on the train, one is the movement of the point of light;The other is relative motion, the movement of a train relative to a stationary track. On a stationary track, there is only one movement, that is, the movement of a point of light along the rail from one end to the other. The movement starts at the same time, and it starts in an instant!
If the direction of our x-axis is from left to right, then the electric shock point A on the rail is the coordinate origin O;Shock point A on the train'It's k'The origin of the system'。When the point of light changes from a(a') departure to another shock point b is time t, then time is t on a moving train' 。
Because the simultaneous time of the same system must be equal, that is to say, the time of the movement of the train relative to the track must be equal to the time of the movement of the light point at the rear of the train. So the time of the system of rest is "divided into two", corresponding to the two motions of the system of motion (train), t'=t 2 , the left half gives relative motion, and the right half gives the light point motion.
The time of the motor system is divided into two parts equally, but the "abundance" of these two equal time and the effect of movement are different. For the train, its speed is obviously less than the speed of light, i.e., there is: u < c At the same time, there is a displacement of the relative motion of the left half (the train) (the black line in the figure), and it is less than the simultaneous displacement of the right half of the light point (the red line in the figure) ut'< ct'x is visible'+ut'< x (1 type) andx'The terminal is b', ut'The beginning is A', they are simultaneous!The algebraic sum of the displacements of two motions, because there is a "gap" between them, is discontinuous, and is less than x of the stationary system, i.e., the distance ab
This is the "shrinkage" of motion, dividing both sides of equation (1) by the speed of light gives t'+ut'c < t and will t'=x'c substituting the left side of the inequality is there (equation 2), which is the "bell slow" effect of motion. Of course, these are the proof conclusions of "slow ruler clock" when moving in the same direction.