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How does a candle burn?
Candles, have been used since ancient times. Although the importance of candles has decreased in the developed world, they can still be found in many households. In the past candles were made either of bees wax or tallow, while today they are usually made of paraffin wax, which does not burn when solid. When we light a candle, the external heat source starts the process, by melting and burning a small amount of wax. When a candle burns, the wax near the wik melts. Molten wax is kept in place, by the room of solid wax. The wik absorbs the molten wax by capillary action, then the molten wax vaporizes in the wik, due to the heat and, burns away. As molten wax is continuously consumed, the flame moves downwards, and develops new layers of wax. The surface of the flame is called the flame front. Combustion takes place around it, which means that it is here, that such particles formed inside the flame, react with the oxygen in the air producing water and carbon dioxide. Oxygen does not reach the inner part of the flame, as it is used up in the flame front during combustion; however the heat generated by combustion, does manage to reach it. The wax evaporating from the wik decomposes due to the heat, then decomposition products generate such particles which burn. This is what causes the flame’s yellow color, the suit particles pass through the flame front, reach the oxygen rich gas and burn. If the wik releases too much wax into the flame, under in such particles are released into the air producing a city flame.
What are the different layers of skin?
The skin covering the outer surface of the human body, is the organ with the greatest mass. It accounts for about fifteen to twenty percent of our total body mass. The skin, has a layered structure consisting of the epidermis, dermis, and hypodermis. The lower layer of the epidermis, the dermis, and in some places the hypodermis contained a variety of receptors which respond to mechanical, thermal and chemical stimuli from the outside world. Receptors are not evenly distributed in the body. The skin on our fingertips, for example, contains a large number of receptors for fine touch. The souls of our feet, however, have a high density of receptors, which detect stronger pressure. The impulses formed in the receptors of the skin, are transmitted to the brain stem, or to the spinal cord, via sensory nerves. This information is processed in the sensory cortex of the cerebral. Pain is triggered by mechanical, thermal and chemical stimuli, which signal a danger to the body. Pain is never a pleasant feeling, yet it is beneficial. It warns you of danger and encourages you to avoid it. Pain is detected in the skin by free nerve endings. Our skin contains a variety of receptors which respond to mechanical stimuli from the outside world. These receptors include tactile corpuscles, which comprise a free nerve ending and capsule. They are sensitive to light touch and are concentrated mostly at the fingertips. The pacinian corpuscles are mechanical receptors located deep in the skin with a structure that resembles a slice of onion. They are sensitive to rapid changes in pressure and vibration, detecting warmth, and thus the resultant cooling of the body are essential to maintaining constant body temperature. Warmth sensitive thermal receptors in the dermis are responsible for detecting warm, when the stimuli detected by the receptors are transmitted to the central nervous system, the blood vessels in the skin dilate and the sweat glands become more active. The evaporation of perspiration on the skin further cools the skin. Detecting cold also helps to maintain a constant body temperature. Cold sensitive thermal receptors in the dermis are responsible for detecting cold, upon detecting cold, the erector pilot muscles contract and the hair on the skin, which is normally flattened against the body, stands on, resulting in better insulation.
How does a Tornado form?
Tornadoes also called twisters or whirlwinds are rapidly rotating columns of air that are in contact with both the surface of the earth and the cumulonimbus cloud. The diameter of tornadoes varies between a few meters and several kilometers. Even though most tornadoes exist for a short period of time they can be extremely powerful and cause a great deal of damage. Tornadoes can form on every continent except Antarctica. Most tornadoes however occur on the Great Plains in the United States because of the geographical features of the region. There are masses with different properties clash in this region cold dry air coming from the west collides with warm humid air coming from the south the Gulf of Mexico. The majority of tornadoes form from rotating thunderstorms called supercells which in turn may form from cumulonimbus clouds in the presence of powerful convective updrafts. The difference in wind speed and direction at different altitudes a phenomenon called wind shear creates a horizontal vertex parallel to the ground. When the convective updrafts of the thunderstorm draws up a section of the horizontal vertex tube a loop is formed and the updraft splits into a pair of counter rotating vortices. It is usually the vortex rotating side clinically that is anti clockwise in the northern hemisphere and clockwise in the southern hemisphere that eventually becomes stronger while the other one dies. This site clinically rotating updraft is called a mesocyclone. When this forms the cumulonimbus reaches the supercell state. Tornadoes may form when the mesocyclone receives a supply of warm and humid air from the surface. At the same time a downdraft is present in the center of the mesocyclone. As the vertical vortex stretches towards the ground the spinning air is drawn inward towards the axis of rotation and therefore it will spin faster. If it becomes fast enough finally emerges from the supercell. If the final reaches the ground it is called a tornado. The tornado sucks in dust and debris from the ground making the lower part of the final darker. In most cases the intensity of the tornado as well as its diameter quickly decreases. Eventually the tornado disappears completely. Most tornadoes last for only a few minutes. However they can still cause significant damage. 3 quarters of all tornadoes do not reach a speed of 180 kilometers per hour. At this speed the only cause moderate damage. Never the less tornadoes attaining several times greater speed can cause massive destruction such as destroying buildings. The enhanced Fujita scale a modified version of the Fujita scale that was created by a Japanese born meteorologist is used to characterize tornadoes. It consists of 6 categories based on tornado intensity and inflicted damage.
How does a Digital Camera work?
The construction of digital cameras, is very similar to that of traditional ones. The most important components are the body, the objective lens, the diaphragm, the shutter, and the light sensitive surface, or image sensor. The difference is that, digital cameras transform the image into electrical signals, and store it in this form too. In the case of traditional cameras, light produces a chemical change in the light sensitive film. Digital cameras, can be grouped into several categories. The best known, are the digital single lens reflex cameras with interchangeable lenses. Mirrorless interchangeable lens cameras are also becoming widespread. Compact cameras do not have interchangeable lenses. Bridge cameras within this category, have a wide zoom range. They represent a transition, between the simplest cameras, and the higher quality DSLR kind. Most digital cameras are also able to record videos. To take excellent photos, we often need accessories besides the camera, because it is difficult to shoot in low light conditions for instance. If there is not enough light, the camera’s shutter has to stay open longer, which may lead to camera shake or the movement of the subject, resulting in a blurry picture. The flash serves as an artificial light source, and the tripod prevents camera shake while shooting. When we take photos light rays are gathered by the objective lens. This is actually a set of lenses, in which the position of the lenses can be changed. This enables us to change magnification, that is we can zoom in on our subject. Image distance the point where light rays converge, can also be adjusted, making our subject to peer in focus. The objective lens comprises several lenses to correct the imperfections caused by lens aberration. The light then travels through the opening in the diaphragm, called the aperture, which regulates the amount of light entering the lens. If there’s too much light, the width of this opening is reduced, and if the light is too low the opening widens. The depth of field can also be adjusted with the aperture. A smaller aperture results in a deeper depth of field, that is the subject and the background are also sharp. A larger aperture however, results in a shallower depth of field, that is, only the subject will be sharp. In single lens reflex cameras, after light passes through the aperture, it reaches a mirror, positioned at an angle, to reflect through a pentaprism, to the view finder. The pentaprism ensures that the image we see in the viewfinder, is not upside down. Some cameras have a semitransparent mirror, with a secondary mirror behind it, that is perpendicular to it. This secondary mirror directs part of the light, towards a focusing screen, and then, a sensor array to operate the autofocus system. When we take photos, the mirror flips up, and the light travels straight through the shutter, which opens at the same time, allowing it to reach the light sensitive surface, that is, the image sensor. The shutter stays open for a short time, if there is a strong light, and longer, in low light conditions. A short exposure time and large aperture, are ideal when shooting moving objects, so that the image will not be blurry. A long exposure time is necessary for taking pictures of the stars at night, and the camera has to be placed on a tripod. Passing through the shutter, the light reaches the light sensitive surface ,or image sensor which comprises millions of photo sites or pixels and is converted into electrical signals, which are processed by the camera’s processor. These are then stored on the memory card, in the same form for each pixel. The ISO sensitivity, the image sensor sensitivity to light, has a very wide range. However, if we raise the ISO number, the amount of noise in the image also increases. Modern cameras adjust the focus aperture shutter speed, and ISO settings automatically, but many other automatic, semi automatic, and manual modes can also be selected. Cameras can take color photos, because tiny red, green, or blue color filters cover each pixel sensor. The cameras electronics thus, know the color of the light the different pixels are captured. In cameras without a reflex mirror, continuously reaches the image sensor, so the image seen by the lens, is always visible on the LCD screen at the back of the camera. This also serves as a viewfinder.
DOCUMENTARIES
JAMES WEBB TELESCOPE A Time Machine
Telescopes, have always been a major breakthrough, in the world of science and astronomy. Since, 1609, when Galileo Galilei used the telescope systematically, to observe and understand celestial objects, and record his discoveries, to the Present. Hubble telescope, a space telescope around the size of large school bus, that opened many secrets of space, including discoveries of Black Hole. The Hubble Space Telescope was the most popular and leading telescope of all times. Launched in 1990, was a supreme telescope, being able to take pictures of many distant galaxies, and planets, in a extremely clear view. Especially the discovery of black hole, was an extraordinary breathtaking image. The Hubble Space Telescope, was a complex Telescope with simple workings. It has a Primary mirror, from where all light reflects into a secondary mirror, which then, reflects onto the camera inside the telescope. Some of publicly shown pictures taken by Hubble are, Distant galaxies, orion nebula cloud, horsehead nebula, spiral galaxy, and few of our solar system’s planets. The advancement, and development of telescopes have never stopped. Entering the JAMES WEBB SPACE TELESCOPE. A project started on 1996, that took 25 years to be launched, around 3 times larger than the Hubble. 6.4 meters of just primary mirrors. A time machine that will let us see the first light emitted by stars and galaxies after the Big Bang. It is a joint project between Nasa, ESA, and CSA. Comets are some of the objects that it will be sending back pictures of. The James Webb Telescope will help astronomers look back in time and explore the Universe’s earliest light—some 13.5 billion years before the present day, when our Sun and Earth formed. The telescope will also help us explore how galaxies form and evolve — which means we can explore different aspects of our own galaxy, the Milky Way Galaxy — and learn more about its history. Some of the questions we hope to answer with this telescope include: How did planets like our Earth form? How did life start? What does a typical galaxy look like and how do galaxies change over time? It was prepared to be launched in 2020, but due to our very known, covid pandemic , it will now be launched in 2021, if nothing goes wrong..The telescope is named after NASA scientist James Webb who was involved in planning space missions for 50 years before his death in 1992. It is being built in French Guiana. It will be a successor to the Hubble Space Telescope and will provide a peek into the Universe when it was only a few hundred years old. As we age, we tend to lose our ability to see things in the night sky because of light pollution from the city. The James Webb Telescope will allow us to see more stars and galaxies, giving us a bit of young Universe inside our living rooms. The telescope is equipped with six mirrors which are able to collect light from distant galaxies. The mirrors are made of beryllium, gold, and silver coated with a special material called “gold nanoparticles” which reflects infrared light. By looking the universe at infrared, which has a longer wavelength than visible light, which means it will be able to see futher away than the Hubble telescope, the universe is expanding, and because of the redshifting of light, the father we look , the faster the objects are moving away from us.. The Hubble Telescope has helped us make great strides in understanding the aging universe. Astronomers now know how old it is, how fast it’s expanding and even what dark matter is. But to really understand the universe more accurately, we needed The James Webb Telescope.
DEEP SEA MONSTERS The Giant Colossal Squid
The Ocean, also known as the mother of life, as Ocean is the place, where life originated, billions of years ago. Even we, humans, have eventually evolved from a fish, from an ocean. The place, also known as carbon sinks, as the oceans are the one, who sucks 50% of carbon from atmosphere to decrease our air toxicity level. The deep sea, is one of the most unexplored places on earth. Humans have only explored around 5% of the ocean’s surface, which makes the deep sea an exciting place to learn about new species and their behaviours. From shallow waters to the extreme depth of Abyss. Ocean sustain a variety of life, fishes, reptiles, slugs, worms, crabs, mammals, corals and plants. Some being cute, some looks sad, some small and tiny, some being immovable. But some creatures do exists that are terrifically dangerous enough, to even kill the largest organism on earth, Whales. The deep sea monsters are a group of creatures that live in the ocean’s deepest parts. These creatures have been around for a while, and have some very interesting tales to tell about their lives in the ocean. The Legendary kraken, an incredible ocean beast of immense size and cephalopod-like appearance in Scandinavian old stories. As indicated by the Norse adventures, the kraken abides off the shorelines of Norway and Greenland and threatens close by mariners. THE GIANT COLOSSAL SQUID, by the name itself, “colossal” , meaning, “terrific” . Found in the depth of 3000 m and extends to wherever humans have reached. The largest Invertebrates on planet. Theories says that the deeper the squid found, the bigger it’s size. People often mistaken the colossal squid with the giant squid, but they are a lot different, where giant squids are known to be fierce active predators. COLOSSAL squids are far more stronger and dangerous than it. It is two times heavier than the giant squid, but the most dreadful part of colossal squids, are it’s tentacles, thorny shaped and venomous, than the giant squid. The COLOSSAL Squid is a member of the cephalopods group, which includes octopuses and squid. They are one of the largest invertebrates in the sea, reaching up to 44 feet long, dwarfing any other known squid species on earth, and weighing nearly half a ton! Able to snatch prey from 33 feets away. The colossal squid has been documented as being more aggressive than other large cephalopods and they will go out of their way to attack humans if they feel threatened or provoked. The Giant COLOSSAL Squid is one of the most mysterious and dangerous sea monsters in history. They can grow to an enormous size and have been known to attack ships. They deeper they are, they might be even bigger than blue whales. And so, they are known to be the Kraken. Their tentacles can grow up to 46 feet long, which is equal to a 20-storey building! The deep sea monsters are the most mysterious creatures dwelling in the ocean depths. They are so different from animals living on land, that they have built their own kingdom. But the giant colossal squid, and the legends of kraken, are just 5% of what we know. Humans are evolving rapidly, not physically, but mentally. As the ongoing development in technologies, humans soon will be able to discover the hidden mysteries of our oceans. Who knows, if the megalodon, or tylosauras, still exists. Or the missing world of Atlantis and Lemuria. Who knows if we have a Godzilla sleeping inside the Mariana Trench, or what Exists beneath our feet. But the limits are not only around our planet, it extends to the end of the universe, discovering infinite lives.
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