Scientists from the Earth using a lot of tools, trying to describe how the nature and the universe as a whole.
that they come to the laws and theories. What is the difference? A scientific law can often be reduced to a mathematical statement such as E = mc²; This statement is based on empirical data and its validity is usually limited to a certain set of conditions. In the case of E = mc² - the speed of light in vacuum.
A scientific theory often aims to synthesize a number of facts or observations of particular phenomena. And in general (but not always), and checks out a clear statement of how nature works. It is not necessary to reduce the scientific theory of the equation, but it really is something fundamental about the nature of the work.
As laws and theories depend on the basic elements of the scientific method, such as the creation of hypotheses, experiments, finding (or not finding) empirical data and drawing conclusions. In the end, scientists should be able to replicate the results, if the experiment is destined to become the basis for obscheprinyatnogo law or theory.
In this article we look at the ten scientific laws and theories that you can refresh your memory, even if you are, for example, do not often turn to scanning electron microscopy. We begin with the explosion and the uncertainty will end.
The Big Bang Theory
If there is to know at least one scientific theory, let it explain how the universe has reached its current state (or reached if disproved). Based on research conducted by Edwin Hubble, Georges Lemaitre and Albert Einstein, the Big Bang theory postulates that the universe began 14 billion years ago with a massive expansion. At some point, the universe has been concluded at one point and cover all the matter in the present universe. This movement continues to this day, and the universe itself is constantly expanding.
The Big Bang Theory has received broad support in scientific circles after Arno Penzias and Robert Wilson discovered the cosmic microwave background in 1965. Using radio telescopes, astronomers have discovered two cosmic noise or static, which does not dissipate with time. In collaboration with the Princeton researcher Robert Dicke, a pair of scientists has confirmed the hypothesis of Dick that the original Big Bang left a low-level radiation, which can be found throughout the universe.
The law of cosmic expansion Hubble
Let's for a moment detain Edwin Hubble. While in the 1920s, the Great Depression was raging, Hubble played a pioneering astronomical research. He not only proved that there were other galaxies besides the Milky Way, but also found that these galaxies are rushing away from our own, and that he called the divergence of the movement.
In order to quantify the rate of galactic motion, Hubble proposed a law of cosmic expansion, it is Hubble's law. The equation looks like this: speed = H0 x distance. The rate is the rate of recession of galaxies; H0 - is the Hubble constant, or parameter, which indicates the rate of expansion of the universe; distance - the distance one galaxy to the one with which the comparison.
The Hubble constant is calculated at different values for quite some time, but now she stopped at a point 70 km / s Mpc. For us it is not so important. It is important that the law is a convenient way of measuring the speed of the galaxy relative to our own. And more importantly, the law established that the universe is composed of many galaxies, the movement of which can be traced to the Big Bang.
Laws of planetary motion Kepler
For centuries, scientists have fought with each other and with the religious leaders of the orbits of the planets, especially for what they revolve around the sun. In the 16th century, Copernicus put forward his controversial concept of the heliocentric solar system, in which the planets orbit the Sun, not the Earth. However, only with the Johannes Kepler, who relied on the work of Tycho Brahe and other astronomers, there is a clear scientific basis for the motion of the planets.
Three laws of planetary motion Kepler, developed in the early 17th century, describe the motion of planets around the sun. The first law, which is sometimes called the law of orbits, says that the planets revolve around the sun in an elliptical orbit. The second law, the law of areas, said that the line joining the planet to the sun, forms the equal areas in equal intervals of time. In other words, if you measure the area, created a line drawn from the Earth from the Sun, and track the movement of the Earth for 30 days, the area will be the same, regardless of the provisions concerning the origin of the Earth.
The third law, the law of periods, allowing to establish a clear relationship between the orbital period of the planet and the distance to the sun. Thanks to this law, we know that the planet, which is relatively close to the sun, like Venus, has a much shorter orbital period than the distant planets like Neptune.
The universal law of gravitation
Today it may be a matter of course, but more than 300 years ago, Sir Isaac Newton proposed a revolutionary idea: two of any object, regardless of their weight, have a gravitational pull on each other. This law represented by the equation, which many students face in higher grades in physics-mathematics.
F = G × [(m1m2) / r²]
F - is the gravitational force between two objects measured in Newtons. M1 and M2 - is the mass of two objects, while r - is the distance between them. G - is the gravitational constant, is now calculated as 6 67384 (80) or 10-11 · m² · h · kg-2.
The advantage of the universal law of attraction is that it allows you to calculate the gravitational attraction between any two objects. This ability is extremely useful when scientists, for example, launch a satellite into orbit, or determine the course of the moon.
Since we are talking about one of the greatest scientists who ever lived on earth, let's talk about other famous Newton's laws. His three laws of motion are an essential part of modern physics. And like many other laws of physics, they are elegant in their simplicity.
The first of the three laws of states that an object in motion stays in motion, if it is not an external force acts. For ball which rolls along the floor, an external force may be friction between the ball and the floor or the boy who hit the ball in the other direction.
The second law establishes a relationship between the mass of the object (m) and its acceleration (a) in the form of the equation F = mx a. F is the force, measured in Newtons. Also, a vector, that is, he has directed component. Due to the acceleration of the ball that is rolling on the floor, it has a singular vector in the direction of its movement, and this is taken into account when calculating the strength.
The third law is quite substantial and should be familiar to you: for every action there is an equal and opposite reaction. That is, for each of the force applied to the object on the surface, the object is pushed with the same force.
The laws of thermodynamics
British physicist and novelist CP Snow once said that the unlearned, who did not know the second law of thermodynamics, was a scientist who had never read Shakespeare. Snow now famous statement stressed the importance of thermodynamics and the need for even people far from science, to know him.
Thermodynamics - the science of how energy works in the system, whether the engine or the Earth's core. It can be reduced to a few basic laws that Snow outlined as follows:
You can not win.
You do not avoid losses.
You can not leave the game.
Let's deal with this. Saying that you can not win, Snow was referring to the fact that since matter and energy are saved, you can not have one without losing the second (ie, E = mc²). This also means that for the engine you need to supply heat, but in the absence of ideal closed-loop system, some heat will inevitably go into the open world, leading to the second law.
The second law - inevitable losses - which means that due to the increasing entropy, you can not return to their previous energy state. The energy concentrated in one place, will always strive to places of lower concentration.
Finally, the third law - you can not quit the game - refers to absolute zero, the lowest theoretically possible temperature - minus 273, 15 degrees Celsius. When the system reaches the absolute zero, the motion of the molecules stops, and hence the entropy reaches its lowest value and there will be even kinetic energy. But in the real world it is impossible to achieve absolute zero - just very close to it go.
After the ancient Greek Archimedes discovered his principle of buoyancy, he allegedly shouted "Eureka!" (I found!) And ran naked through Syracuse. So the story goes. The discovery was so important here. Also, legend has it that Archimedes discovered the principle, when he noticed that the water in the bath rises when immersed in his body.
According to Archimedes' principle of buoyancy, the force acting on submerged or partially submerged object, equal to the mass of liquid that displaces the object. This principle is essential in calculating the density and design of submarines and other ocean vessels.
Evolyutsiya and natural selection
Now that we have established some of the basic concepts of why the universe began and how physical laws influence our daily lives, let's turn our attention to the human form and figure out how we got to this. According to most scientists, all life on earth has a common ancestor. But in order to form such a huge difference between all living organisms, some of which have been turned into separate species.
In a general sense, this differentiation has occurred in the course of evolution. The populations of organisms and their characteristics have been through mechanisms such as mutation. Those traits were more favorable for survival, such as brown frogs, which are perfectly camouflaged in the swamp have been naturally selected for survival. That's where I got the beginning of the term natural selection.
You can multiply these two theories on the long, long time, and actually did Darwin in the 19th century. Evolution and natural selection explain the huge variety of life on Earth.
The general theory of relativity, Albert Einstein was and remains the most important discovery that will forever change our view of the universe. The major breakthrough of Einstein was a statement about that space and time are not absolute, and gravity - is not just a force applied to an object or an array. Rather, gravity is related to the fact that mass distorts space-time itself (space-time).
To understand this, imagine that you go through the entire Earth in a straight line to the east, for example, from the northern hemisphere. After a while, if someone wants to pinpoint your location, you'll be far south and east of its original position. This is because the Earth is curved. To go straight to the east, you will need to take into account the shape of the Earth and go at an angle slightly to the north. Compare round ball and a sheet of paper.
Space - is largely the same. For example, to ensure missile flying round the Earth, it will be apparent that they fly in a straight line in space. But in fact, the space-time around bends under the influence of the Earth's gravity, causing them to move forward at the same time and remain in Earth orbit.
Einstein's theory has had an enormous impact on the future of astrophysics and cosmology. She explained the small and unexpected anomaly in the orbit of Mercury, showed how starlight is bent and laid the theoretical foundations for black holes.
The Heisenberg uncertainty principle
Expansion of Einstein's relativity theory tell us more about how the universe works, and helped lay the foundation for quantum physics, which led to a completely unexpected discomfiture of theoretical science. In 1927, the realization that all laws of the universe in a certain context are flexible, led to the discovery of a runaway German scientist Werner Heisenberg.
Postulating his uncertainty principle, Heisenberg realized that it is impossible to know at the same time with high accuracy two properties of the particles. You can know the position of an electron with a high degree of accuracy, but its momentum, and vice versa.
Later, Niels Bohr made a discovery that helped to explain the principle of Heisenberg. Bohr found that the electron has the qualities of both particles and waves. The concept became known as wave-particle duality, and became the basis of quantum physics. Therefore, when we measure the position of an electron, we define it as a particle at a particular point in space with indefinite wavelength. When we measure the momentum, we consider the electron as a wave, and thus can know the amplitude of its length, but not the position.