Large Magellanic Cloud

The Large Magellanic Cloud (LMC) is a nearby irregular galaxy, and is a satellite of the Milky Way. At a distance of slightly less than 50 kiloparsecs (≈160,000 light-years), the LMC is the third closest galaxy to the Milky Way, with the Sagittarius Dwarf Spheroidal (~ 16 kiloparsecs) and Canis Major Dwarf Galaxy (~ 12.9 kiloparsecs) lying closer to the center of...

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Critical Angle

Critical angle is the angle at which the light ray travelling form a denser medium to a rarer medium grazes along the surface rather than escaping directly. The angle of refraction in 90° for the angle of incidence equal to critical angle. A ray of light which is incident of the boundary separating the two optical mediums is incident at angle greater than critical angle will get reflected. This phenomenon is called Total Internal Reflection. The...

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How does our phone Vibrate?

There is a device that takes vibration to high-tech extremes. Any parent whose child owns a Tickle-Me-Elmo doll has experienced this technology. Elmo has a vibration system (designed to simulate body-shaking laughter) that is powerful enough to cause many children to drop the toy. The vibration system inside a pager works exactly the same way on a smaller scale, so let's use Elmo as an example. Inside the control unit (on the right hand side...

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UV rays

Ultraviolet (UV) light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV. It is named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the colour violet. These frequencies are invisible to humans,...

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Infrared Radiations

Infrared (IR) light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres (µm), and extending conventionally to 300 µm. These wavelengths correspond to a frequency range of approximately 1 to 400 THz, and include most of the thermal radiation emitted by objects near room...

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Rainbow

When Sunlight falls on small water droplets suspended in air during or after a rain, it suffers refraction, Total Internal Reflection(TIR) and dispersion. If an observer has the Sun at the back and water droplets in front of himself, then the person may see two rainbows one inside the other. The inner one is called primary rainbow and the outer one is called the secondary rainbow. A ray of light when passing from air to water suffers refraction,...

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How to Spot Venus and Jupiter

Venus (on the left) and Jupiter in the evening sky in 2008. This week their positions will be reversed.   After the moon, they are the two brightest objects in the night sky, and for the next few evenings they will appear side-by-side in western skies in a dazzling heavenly spectacle. Though Jupiter is seven times farther from Earth than Venus, the planets' orbits bring them into close approach on Tuesday...

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Radio Waves

Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light. Radio waves have frequencies from 300 GHz to as low as 3 kHz, and corresponding wavelengths from 1 millimeter to 100 kilometers. Like all other electromagnetic waves, they travel at the speed of light. Naturally occurring radio waves are made by lightning, or by astronomical objects. Artificially generated radio waves...

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Electromagnetic Radiations

The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation. The "electromagnetic spectrum" of an object is the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. The electromagnetic spectrum extends from low frequencies used for modern radio communication to gamma radiation at the short-wavelength (high-frequency)...

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Newton's Laws of motion

Newton's laws of motion are three physical laws that form the basis for classical mechanics. They describe the relationship between the forces acting on a body and its motion due to those forces. They have been expressed in several different ways over nearly three centuries, and can be summarized as follows: First law: Every body persists in its state of being at rest or of moving uniformly straight...

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Cohesive and Adhesive Forces

Cohesion: Cohesion or cohesive attraction or cohesive force is the action or property of like molecules sticking together, being mutually attractive. This is an intrinsic property of a substance that is caused by the shape and structure of its molecules which makes the distribution of orbiting electrons irregular when molecules get close to one another, creating electrical attraction that...

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Big Bang Theory

The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in its present continuously expanding state. According to the most recent measurements and observations,...

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