10 scientific laws and theories that everyone should know




Scientists from Earth using mass instruments, trying to describe how nature works and the universe as a whole. That they come to the laws and theories. What’s the difference? Scientific law can often be reduced to a mathematical statement, like E = mc ²; this assertion is based on empirical data and its validity is usually limited to a certain set of conditions. In the case of E = mc ² – speed of light in vacuum.

Scientific theory often seeks to synthesize a series of facts or observations of specific phenomena. And in general (but not always) goes clear and verifiable statement about how nature works. Does not necessarily reduce the scientific theory of the equation, but it actually represents something fundamental about the nature of the work.

As laws and theories depend on the basic elements of the scientific method, for example, the creation of hypotheses, experiments, finding (or not finding) empirical data and drawing conclusions. Eventually, 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 ten of scientific laws and theories that you can refresh your memory, even if you, for example, not so often refer to the scanning electron microscope. We begin with the explosion and finish uncertainty.
The Big Bang Theory

If worth knowing at least one scientific theory, let it explain how the universe has reached its current state (or not reached, if refuted ). Based on studies conducted by Edwin Hubble, Georges Lemaitre, and Albert Einstein, the Big Bang theory postulates that the universe began 14 billion years ago with the massive expansion. At some point the universe was made at one point and covered the whole matter of the current universe. This movement continues to this day, and the universe itself is constantly expanding.

The Big Bang Theory has received broad support in the scientific community after Arno Penzias and Robert Wilson discovered the cosmic microwave background in 1965. Radio telescopes, astronomers have discovered two cosmic noise or static, which does not dissipate over time. In collaboration with Princeton researcher Robert Dicke, a pair of scientists has confirmed the hypothesis Dicke that the initial Big Bang left behind a low-level radiation, which can be found throughout the universe.
Hubble law cosmic expansion

Let us for a moment detain Edwin Hubble. While in the 1920s Great Depression raged, Hubble gave a groundbreaking 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 movement.

In order to quantify the rate of this galactic motion, Hubble proposed a law of cosmic expansion, aka Hubble’s law. The equation looks like this: rate = H0 x distance. Speed ​​is the speed of recession of galaxies; H0 – is the Hubble constant, or parameter, which shows the rate of expansion of the universe, the distance – the distance one galaxy to the one from which there is a comparison.

Hubble constant is calculated for different values ​​of for quite some time, but now it froze at 70 km / s Mpc. For us it is not so important. It is important that the law is a convenient way to measure the speed of the galaxy relative to our own. And more importantly, the law established that the universe consists of many galaxies, whose motion can be traced to the Big Bang.
Kepler’s laws of planetary motion

For centuries, scientists have fought with each other and with religious leaders in the orbits of planets, especially for what they revolve around the sun. In the 16th century, Copernicus put forward his controversial concept of a heliocentric solar system in which the planets revolve around the sun and not the Earth. However, only with 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, established in the early 17th century, describe the motion of planets around the sun. The first law, which is sometimes called the law of orbits, argues 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 equal areas in equal intervals of time. In other words, if you measure the space created by the drawn line from the Earth to the Sun, and track the movement of the earth for 30 days, the area will be the same, regardless of the position regarding the origin of the Earth.

The third law, the law of periods, allows 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 distant planets like Neptune.
The universal law of gravitation

Today it can be in the order of things, but more than 300 years ago, Sir Isaac Newton proposed a revolutionary idea: two any object, regardless of their mass, have a gravitational pull on each other. This law represented by the equation with which many students face in high school physics-mathematics.

F = G × [(m1m2) / r ²]

F – is the gravitational force between two objects is measured in newtons. M1 and M2 – is the mass of the two objects, while r – is the distance between them. G – is the gravitational constant, is currently calculated as 6.67384 (80) × 10 -11 or Nm ² · kg -2.

The advantage of the universal law of gravitation is that it allows us to calculate the gravitational attraction between any two objects. This ability is extremely useful when scientists, for example, is launching a satellite into orbit, or determine the course of the moon.
Newton’s Laws

Since we’re 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, unless it is an external force. 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 opposite direction.

The second law establishes a relationship between the mass of the object (m) and acceleration (a) in the form of the equation F = mx a. F is the force, measured in Newtons. As a vector, ie, it has a directional component. With acceleration, a ball that rolls on the floor, has a singular vector in the direction of its movement, and this is taken into account when calculating the force.

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 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 removed from science to know it.

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 that. Saying that you can not win, Snow meant that since matter and energy are saved, you can not have one without losing the second (ie, E = mc ²). Also, it means that engine operation you need to supply heat, but in the absence of a closed system ideally some heat will inevitably go into the open world, leading to the second law.

The second law – losses are inevitable – means that due to the increasing entropy, you can not return to their previous energy state. Energy concentrated in one place, will always seek to places of lower concentration.

Finally, the third law – you can not get out of the game – refers to absolute zero , the lowest temperature theoretically possible – minus 273.15 degrees Celsius. When the system reaches absolute zero, molecular motion stops, and hence the entropy reaches the lowest value and would not even kinetic energy. But in the real world to achieve absolute zero is impossible – just very close to approach him.
Archimedes force

Once an ancient Greek Archimedes discovered his principle of buoyancy, he allegedly shouted “Eureka!” (Nashel!) and ran naked through Syracuse. So the legend 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 fluid which moves the object. This principle is crucial in density calculations, as well as the design of submarines and other ocean vessels.
Evolyutsiya and natural selection

Now that we have established some of the basic concepts of how to get started in the universe and how physical laws affect our daily lives, let’s turn our attention to the human form and find 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 them had become a separate species.

In a general sense, this differentiation occurred during evolution. Populations of organisms and their features have been through mechanisms such as mutations. Those traits were more favorable for survival, such as brown frogs that perfectly camouflaged in the swamp, were naturally selected for survival. That’s where he took the beginning of the term natural selection.

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.
General theory of relativity

The general theory of relativity, Albert Einstein was and remains the most important discovery that forever changed our view of the universe. Einstein was a major breakthrough statement that space and time are not absolute, and gravity – it is not just the force applied to an object or mass. Rather, gravity is related to the fact that mass curves space and time itself (space-time).

To understand this, imagine that you are traveling through the entire Earth in a straight line in an easterly direction, say, from the northern hemisphere. After a while, if someone wants to pinpoint your location you will be much farther south and east of its original position. This is because the Earth is curved. To go directly 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 piece of paper.

Space – is largely the same. For example, to ensure missile flying round the Earth, it will be apparent that they travel in a straight line in space. But in fact, the space-time around them is bent by the force of Earth’s gravity, causing them both to move forward and remain in Earth orbit.

Einstein’s theory has had an enormous impact on the future of astrophysics and cosmology. She explained a small and unexpected anomaly of Mercury’s orbit, showed how light bends stars 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 embarrassment of theoretical science. In 1927, the realization that all the laws of the universe in a particular 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 particle properties. 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 Heisenberg principle. Bohr discovered that the electron has the qualities both particles and waves. The concept became known as wave-particle duality, and formed the basis of quantum physics. Therefore, when we measure the position of an electron, we define it as a particle in a particular point in space with an 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.
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