Science Questions and Facts
What causes a rainbow?
Science Questions : There is something special about this atmospheric phenomenon that arouses awe in people since ancient times. According to the Book of Genesis, the Lord laid the rainbow on the sky after the Great Flood and told Noah that it was “a sign of agreement between Me and the earth.” The ancient Greeks went further and decided that the rainbow is the goddess Iris. True, she had an ominous figure – she was announcing war and retribution. For centuries, great minds, from Aristotle to Descartes, have been trying to figure out what process generates the rainbow multi color.
Now, of course, scientists are well aware of this. The rainbow is caused by water droplets that remain suspended in the atmosphere after a good rainfall. The density of the droplets differs from the density of the ambient air, because when sunlight enters them, they act as tiny prisms, breaking light into compound wavelengths, and then reflecting them back. An arc with bands of visible spectrum appears, which we see. Since the drops should reflect the light to us, to see the rainbow, you need to be back to the sun. You also need to look from the ground at an angle of about 40 degrees – this is the angle of the rainbow deviation, that is, the angle at which it refracts the sunlight. It is also interesting that, being on the plane, you can see the rainbow in the form of a disk, rather than an arc.
What is the theory of relativity?
Science Questions : When someone mentions the “theory of relativity”, two theories, special and general, that were developed by physicist Albert Einstein at the beginning of the 1900s are usually meant. Regardless of the degree of our veneration of Einstein, people far from science have little knowledge of his theories. Einstein himself came up with a good way of explaining: “When a man sits with a pretty girl for an hour, it seems to him that a minute has passed. But let him sit on the hot stove for a minute, and she will seem to him longer than an hour. Everything is relative”.
It seems that everything is clear, although the details, of course, are more complicated. Prior to Einstein, everyone largely believed that space and time are stationary and monotonous, never change, from which point on Earth you would not look at them. But Einstein used mathematics to prove that an absolute view of things is an illusion. In fact, space and time change: space can contract, expand, bend, and time flows at different speeds, depending on the speed of the object or the force of the gravitational field.
In addition, the manifestation of space and time can depend on the point of observation of a person. Imagine, for example, that you are looking at an old ticking clock. Now put this clock on Earth’s orbit so that they move at a tremendous speed compared to your position on Earth. The clock in the orbit will tick more slowly.
The clock is slower because of the phenomenon of “slowing down time”. Space and time are in fact parts of one whole space-time that can be distorted by gravity and acceleration. Therefore, if the object moves very fast or is affected by a very powerful gravitational field, the time for this object will go slower compared to an object that is not subjected to the same effect. With the help of mathematical calculations, one can predict how time will slow down for fast moving objects.
This probably sounds strange. But it’s true. GPS satellites, which depend on accurate time measurement and make up a map of the Earth, are a good example. Satellites fly around the planet at a speed of about 14,000 kilometers per hour, and if engineers did not correct the clock with regard to relativity, then a day later Google maps would have been mistaken for almost 10 kilometers during positioning.
Why are bubbles round?
Science Questions : Yes, the bubbles are not always perfectly round, as you must have noticed if at least once they were inflated. But the bubbles tend to be spherical, and you can see that even the longest of them tend to become round. The fact is that the bubbles are essentially thin layers of liquid, the molecules of which are held by a phenomenon called cohesion. This creates a surface tension – a barrier that prevents objects from penetrating through it. But this is not the only force that acts on this layer. Outside, the molecules of air are pressed. The most effective way for the liquid layer to counteract these forces is to adopt the most compact form, which is a sphere, if we calculate the volume-to-area ratio.
What is remarkable, scientists have long learned to make non-circular bubbles – cubic, rectangular (pulling a thin layer of liquid on the wire frame), whatever.
What are the clouds made of?
Science Questions : We hope that we will not disappoint anyone, but the clouds in fact are not a mixture of ice cream and angelic feathers. Clouds are the visible mass of water droplets or ice crystals, or mixtures of both that are suspended above the surface of the Earth. Clouds arise when moist warm air rises. When it rises higher and reaches cold zones, warm air cools, and water vapor condenses in tiny water droplets or ice crystals, depending on the temperature. These drops and crystals remain knocked together due to the principle of cohesion, which we discussed just above. Thus a cloud is born. Some clouds are thicker than others, because they have a higher density of water droplets.
Clouds are a key part of the hydrological cycle of our planet, during which water constantly moves between the surface and the atmosphere, changing between a liquid, solid and gaseous state. If it were not for this cycle, life on our planet might not have existed.
In 1803, meteorologist Luc Howard singled out four major classifications of clouds, which today have Russian and Latin names. Cumulus, or cumulus clouds, is the heap of clouds that we often see in the sky. Cirrus, cirrus clouds, which means “hair” in Latin, are light feathers at height, thin as strands of hair. Plain and ordinary clouds are layered stratus, which means “layer” in Latin. There are also clouds of nimbus, low and gray rain clouds. However, subspecies and varieties of clouds, as well as their mixtures are slightly larger.
Why does water evaporate at room temperature?
Science Questions : We people are used to thinking about reality as a good stable place where different things remain in their places, unless we want to move them. But the reality is different. If you look at the water at the molecular level, the molecules will look like a flock of puppies that are fighting for the best positions on the mother’s belly. When a lot of water vapor collects in the air, the molecules stumble onto the surface and adhere to it, as a result of which condensate forms on the outside of the cold drink on a wet day.
Conversely, when the air is dry, the water molecules in your cup can stick to other molecules floating in the air. This process is called evaporation. If the air is dry enough, more molecules will pass from the cup to the air, rather than drop out of the air into the cup. Over time, water will lose more and more molecules, and eventually you will end up with an empty cup.
The ability of molecules from a liquid state to jump into the air and stick to it is called vapor pressure because the bouncing molecules exert force, as well as gas or a solid that presses on something. Different liquids have different vapor pressures. For acetone, for example, this indicator is high, that is, it evaporates easily. Olive oil, on the contrary, has a low vapor pressure and is unlikely to evaporate at room temperature.
How does natural selection work?
Science Questions : Like the age of the Earth, the theory of evolution – first developed by the biologist Charles Darwin in the mid-1800s – is a separate topic that people do not know but like to discuss. Nowadays opponents of the theory of evolution try to remove it from the curriculum at schools or that children study the “science of creation” in an appendage to the theory of evolution.
And there is one idea for which opponents of evolution are clinging: natural selection, the central concept of Darwin. It is quite easy to understand this idea. In nature, mutations-that is, a permanent change in the genetic program of micro-organisms that will subsequently distinguish the species from its predecessor-occur accidentally. But evolution, a long process in which animals and plants have undergone many changes over many generations, is not accidental. As a rule, changes in organisms become more common over time if they help the body to survive and multiply.
For example, imagine that some beetles are green, but because of the mutation they turn brown. Brown beetles merge with the environment better than green beetles, so they are not often eaten by birds. They survive more, they are reproduced in greater numbers, and these changes are not temporary, but already permanent. Over time, the population of beetles will turn brown. But this is the simplest option. In practice, natural selection takes as a basis for the average, and not specific representatives, and to highlight this process is not very simple.
Will the sun go out someday?
Science Questions : If you think that the Sun for a person stops shining, when he experiences hard periods of his life, then in reality everything is not so. The irony is that the reality around us – the light of the sun, the singing of birds – is more durable than our fragile feelings. Unless you were born 5.5 billion years later. At this moment, like the other star, like a giant thermonuclear reactor, the Sun will exhaust all the hydrogen in its core and start burning hydrogen in the surrounding layers.
This will be the beginning of the end of the Sun – the core will shrink, and the outer layers will expand, and the star will become a red giant. In the final flash, the Sun will burn the solar system with a heat explosion that turns even the cool surroundings of Pluto and the Kuiper belt into a heavenly sauna. Internal planets, including the Earth, will be sucked by a dying giant or turn into ashes.
However, if people do not colonize the solar system or other stars, no one will know about this final hell. The sun, which has already outlived half its life span, is gradually heating up, and after a billion years will be 10% more. Increases in solar radiation will be enough to evaporate all the terrestrial oceans, leaving us without water and other joys of life.
How do magnets work?
Science Questions : For a long time, magnets were considered something of a miracle. And it’s sad, because understanding the principle of their work is quite simple. A magnet is any object or material that has a magnetic field. That is, a bunch of electrons in it float in one direction. Electrons like to form pairs, and in iron. Therefore, objects of solid iron or even with a large amount of iron will be attracted to a sufficiently powerful magnet. Substances and objects attracted to magnets are called ferromagnetism.
People have known about magnetism since time immemorial. In nature, magnets are found, and medieval travelers have learned to magnetize the steel arrows of compasses, that is, create their own magnetic fields. Such magnets were not particularly strong, but in the 20th century, scientists developed new materials and chargers that led to the creation of powerful permanent magnets. You can create an electromagnet from a piece of iron, wrapping it with an electric wire and attaching its ends to the poles of a large battery.
Scientific research is continuing. The level of education of the population is growing. Surrounded by technological wonders, from portable electronics to communication satellites, we must be smart as hell and understand the Science Questions : science, right? The problem is that we (well, not us, but many) are terrible ignoramuses if it comes to fundamental scientific knowledge. Only 53% of people know that the Earth is turning around the Sun in a year, and only 59% of people know that the first people and dinosaurs lived at different times, and not like in the “Flintstones”. Only 47% of people accurately answer that 70% of the Earth’s surface is covered with water.
Obviously, although we have come a long way, there are still many steps ahead before we achieve universal scientific literacy. But for those of you who are desperate to change the subject, when someone mentions the Higgs boson, supercomputers or begins to argue that dinosaurs had feathers, there is a good reason to read this article. This article is about ten scientific issues, answers to which everyone should know.
Why the sky is blue?
Science Questions : We see a blue or blue sky, white feathers of clouds or heavy thunderclouds. But we still like the blue sky more than the cloudy sky. European scientists found that the light of the blue part of the spectrum positively affects emotions, forcing us to respond more sensitively to emotional stimuli and to adapt to emotional difficulties.
But we will not be distracted. The sky seems blue because of the so-called scattering effect. Sunlight must pass through the earth’s atmosphere, filled with gases and particles, which are barriers to sunlight. If you have ever held a prism in your hand, you know that light consists of a pile of different colors, each of which has a different wavelength. In blue, the wavelength is relatively short, so it passes through this filter lighter than colors with longer wavelengths, and as a result it dissipates more widely as it passes through the atmosphere. That’s why the sky seems blue when the sun is high in the sky.
At dawn and dusk, however, the sun’s rays must travel a greater distance to reach their position. This negates the advantage of the wavelengths of blue and allows us to see other colors – often red, orange or yellow.
You ask why the sky is not purple? The violet wavelength is even shorter. But the solar spectrum is uneven, and the violet color in it is smaller, besides the eye is more sensitive to blue and less – to purple.
What is the age of the Earth?
Science Questions : Probably, no New Year on our planet is not complete when someone does not say seriously: “I can not believe that the Earth is 2015 years old!”. Or 2016, or 2017 … The present age of the Earth has long been the subject of bitter disputes. Back in 1654, a scientist named John Light foot, whose calculations were based on the biblical Book of Genesis, proclaimed that the Earth was created at 9 am Mesopotamian time on October 26 in 4004 BC. e. In the late 1700s, the learned Count Buffon warmed up his small copy of the planet and measured the speed with which it cooled down, and based on this data he estimated the age of the Earth at 75,000 years. In the 19th century physicist Lord Kelvin defined the age of the Earth in 20-40 million years.
But all this went down with the discovery of radioactivity. Subsequent calculations showed the rate at which different radioactive substances decay. Scientists of the Earth used this knowledge to determine the age of the Earth’s rocks, as well as samples from meteorites and pebbles, brought from the moon by astronauts. They looked at the state of decay of lead isotopes from stones, and then compared with a scale that showed how lead isotopes change with time. The Earth was formed about 4.54 billion years ago with an error of less than one percent.