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Why Blue is Hotter than Red?

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Why Blue is Hotter than Red? by E. Pasion   Poets say “red hot” and “cold as blue”. In arts, warm tones are associated to red, orange and yellow while cool tones are that of the opposite end of the color spectrum – blue and violet.   However, isn’t it contradicting to what scientists say? The hottest stars for example are the blue hypergiant ones while the coolest ones are the red stars!    Which color really has the highest energy? Which one has the least?   To answer that boggling question, we need to review the color spectrum of the visible light!     What is light?   White light is the combination of all colors in the electromagnetic spectrum. Light is the presence of all colors while black is the absence of all of it! As you have learned in Grade 7, light is a part of the electromagnetic wave or the EM wave! The EM wave is composed of seven different components. These components (in increasing energy) are radio wave, microwave, infrared, visi...
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Things I Should Know About Sound

If you are a Grade 8 Student and you are here to have an advance reading of your lesson on sound, probably you have to consider these important things to review on from your previous lesson in Grade 7. What are the things you should know about sound before tackling the Most Essential Learning Competency (MELC) investigate the effect of temperature to the speed of sound . What is Sound? Sound is a traveling disturbance which carries with it energy. Sound is a form of energy and a wave. The energy of sound (or sound per se) is transmitted by vibrations of the medium at which the sound travels.  Sound is a form of energy that is perceived by the ear. It is audible. However not all sound frequencies could be perceived by the human ear. There are sound that we could not hear! Our human ear is sensitive only to sounds that are within 20 hertz to 20,000 hertz. Sound that have frequencies below 20 hertz are called infrasonic sound. Sound with frequencies above 20,000 hertz are called ultra...
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Why it Sounds Noisier on a Hot Day?

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What happens to sound on a hot day? Does air temperature affect speed of sound? Why it sounds noisier on hot weather conditions? Sound is a traveling disturbance that travels through matter - solid, liquid or gas. It is a mechanical wave that is propagated by the vibrations of particles in a medium. A medium is the material at which wave travels.  Sound is a longitudinal mechanical wave . A longitudinal wave is a type of mechanical wave that propagates by compression and rarefaction.   Compression is a region of high pressure where particles of the medium are forced to compress or move closer together. Rarefaction , on the other hand, is a region of low pressure where the particles of the medium are rarefied or move farther away from each other. Particles of a medium in longitudinal wave vibrates back and forth parallel to the direction of the wave. The wavelength of a longitudinal wave is the distance measured from one compression to the next compression or from one rarefact...
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What is Kinetic Energy and How to Compute It?

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Kinetic Energy   is the energy possessed by an object by virtue of its motion. Kinetic Energy is a consequence of the object’s velocity. Because of its motion, the object is capable of performing work, or transferring energy.   A bowling ball that is made to roll along the bowling lane possess kinetic energy. The kinetic energy of the bowling ball depends on two variables - its mass and its velocity. Kinetic energy is directly proportional to mass. A heavier object has more kinetic energy than a lighter one, granted both objects are moving at the same speed.    A heavier truck posses more kinetic energy than the smaller truck. The KE of the 5000 kg truck is 250,000 J at 10 m/s velocity while the 10,000 kg truck has a KE of 500,000 J In terms of velocity, the faster the ball rolls, the greater is its kinetic energy. In fact, the relationship between kinetic energy and velocity is a direct square relationship. Kinetic energy is directly proportional to the square of t...
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GRAVITATIONAL POTENTIAL ENERGY

Gravitational Potential Energy  ( PE grav ) is the energy possessed by an object by virtue of its position with respect to the ground. Objects that are raised to a certain height possess gravitational potential energy.  Every material object on earth is attracted to the earth's gravitational pull. When lifting a box, for example, you spend energy to raise it to a certain height. Thus, you perform work on the box.  Work   is a process of transferring energy. The amount of work ( Work = Force x displacement) you perform on the box is equal to the potential energy gained by the box.  While a box is lifted, it goes against the pull of gravity. This makes the box of a particular weight (weight = mass x gravity) more difficult to be lifted as height increases. In effect, since more work is needed to raise an object at a higher position, the more gravitational potential energy is gained by that object. The gravitational energy of an object is computed by   PE gra...
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