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Blog Entries posted by Jasmine24

  1. Jasmine24
    Wind is the flow of gases on a very large scale. Wind is caused by the differences of pressure in the earth’s atmosphere. Wind is caused by two major factors on the planet earth. The first being the sun and the second being the rotation of the planet. The sun does not heat up the earth’s atmosphere evenly, as most of the solar energy is absorbed at the equator. When the air becomes heated it expands creating an area of higher pressure. Diffusion causes this area of higher pressure to move to an area of lower pressure. On a very large scale this would massive amounts of air to travel from one area to another, creating vast amounts of kinetic energy that can be harnessed by humans through the use of a wind turbine.

    A wind turbine is used to harness the kinetic energy of vast amounts of wind, and transform it into electricity. This can be shown with a very simple calculation. First we need to remember that wind is an air mass moving from an area of high pressure to an area of low pressure. This movement of air is kinetic energy and can be shown by the formula:

    KE= 1/2 MV^2

    KE= kinetic energy
    M= Mass
    V= Velocity

    Thanks for Reading
  2. Jasmine24
    We know that moving objects have momentum. Unless an outside force acts on an object, the object will continue to move at its present speed and direction. Cars consist of several objects, including the vehicle itself, loose objects in the car and, of course, passengers. If these objects are not restrained, they will continue moving at whatever speed the car is traveling at, even if the car is stopped by a collision. Stopping an object's momentum requires force acting over a period of time. When a car crashes, the force required to stop an object is very great because the car's momentum has changed instantly while the passengers' has not -- there is not much time to work with. The goal of seat belts and air bags is to help stop the passenger while doing as little damage to him or her as possible. What an airbag wants to do is to slow the passenger's speed to zero with little or no damage. The constraints that it has to work within are huge. The airbag has the space between the passenger and the steering wheel or dashboard and a fraction of a second to work with. Even that tiny amount of space and time is valuable, however, if the system can slow the passenger evenly rather than forcing an abrupt halt to his or her motion. Researches are still studying new ways to make airbags more effective and safe with crash dummy's. Thanks for reading
  3. Jasmine24
    A great place to begin to understand the physics of nuclear weapons is with Einstein's most famous equation: E = m*c*c. This equation associates energy E with mass m. The constant of proportionality is the square of the speed of light c. Because c is rather large (3E8m/s), the equation suggests there is a lot of energy associated with even a small amount of matter. In fact one kilogram of matter contains 9E16 Joules of energy, which is roughly the amount of energy released by a hydrogen bomb. Chemical reactions, such as the combustion of petrol in car engines, free less than a billionth of the energy stored in the mass of the fuel, since they do not involve the atomic nuclei, where most of the mass is stored. However, in nuclear reactions the trick of releasing a large proportion of the bound up energy becomes possible.

    Two kinds of nuclear reaction may be used to release energy on a large scale. Fission is the splitting of heavy atomic nuclei into pairs of lighter nuclei, while fusion is the marriage of two light nuclei to form the nucleus of a heavier atom. When (protons and neutrons) come together to form an atomic nucleus, the nucleus is found to weigh less than the sum of the masses of the nucleons. The difference is the mass of the energy released when the nucleons combine (the so-called "binding energy"). It turns out that the binding energy per nucleon, which is also known as the "mass defect", varies for different sizes of nuclei. If on average more than one of these product neutrons goes on to cause a further fission, then successive generations of fissions involve exponentially increasing numbers of atoms in a nuclear chain reaction.

    Nuclear weapons are in themselves morally neutral: they can be used to do good as well as evil, for instance, by destroying or deflecting an asteroid, which threatens to collide with the Earth. However, in the hands of irresponsible people nuclear weapons present a great threat to the future well being of the world.
  4. Jasmine24
    The Composition of stars is a very important and interesting field for astronomers. Stars begin their life when an ordinary dense cloud of interstellar matter becomes unstable and begins to collapse. The composition of such a cloud of matter determines the composition of the star which results from the collapse. Astronomers study the spectrum of the Sun to determine it's chemical composition, since it is the biggest star we are familiar with. In the visible region alone, from 4000 to 7000 angstroms (10-10 Meters), there are thousands of absorption lines in the solar spectrum. These lines have been cataloged, and tell us that there are 67 chemical elements identified in the Sun. There are probably even more elements in the Sun that are present in such a small amount that our most modern instruments can't detect them.

    10 Most common elements in the Sun

    Hydrogen is the most abundant element in the Sun, followed by helium. Those two together make up 99.9 percent by number of the total atoms in the Sun! This is also what we find in the composition of the Universe as a whole. When other stars are studied it is found that most stars are composed of around 70 percent hydrogen and 28 percent helium by mass, very similar to what we see in the Sun. The Sun burns hydrogen into helium at it's center, or "core". This is the chain of nuclear fusion that powers the Sun. The net effect is that four hydrogen nuclei combine to create one helium nucleus, some gamma radiation and two neutrinos. The gamma-ray photons slowly lose energy as they pass through the solar interior, and the energy eventually escapes in the form of visible light!
  5. Jasmine24
    I have a very large interest in bees, so for my first blog post I've decided to research how bees see colors differently compared to humans. Through my research I have discovered that the color spectrum of bees is shifted when compared to the color spectrum of humans.

    Visible light is part of a larger spectrum of energy. Bees can see ultraviolet – a color humans can only imagine – at the short-wavelength end of the spectrum. So it’s true that bees can see ‘colors’ we can’t. Many flowers have ultraviolet patterns on their petals, so bees can see these patterns. They use them as visual guides – like a map painted on the flower – directing them to the flower’s store of nectar. Some flowers that appear non-descript to us have strong ultraviolet patterns. Being a bee doesn’t necessarily mean you live in a more colorful world. Bees can’t see red – at the longer wavelength end of the spectrum – while humans can. To a bee, red looks black.

    Humans see light in wavelengths from approximately 390 to 750 nanometers (nm). These wavelengths represent the spectrum of colors we can see. Bees, see from approximately 300 to 650 nm. That means they can’t see the color red, but they can see in the ultraviolet spectrum (which humans cannot). Bees can also easily distinguish between dark and light – making them very good at seeing edges. This helps them identify different shapes, though they can have trouble distinguishing between similar shapes that have smooth lines – such as circles and ovals. Vision is important to bees, because they feed on nectar and pollen – and that means they have to find flowers. Bees can use odor cues to find a perfect flower, but that only works when they’re already pretty close. Vision is essential to help the bees find flowers at a distance.

    A bees Vision in responce to different colors:
    Red -> black
    Yellow -> yellow-green
    Orange -> yellow-green (darker)
    Green -> green
    Blue -> blue plus ultraviolet blue
    Violet -> blue plus ultra violet
    Purple -> blue
    White -> blue green
    Black -> black

    In conclusion, bees have a very unique color vision.
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