Wednesday, 4 May 2016
Animals planning war
Sunday, 27 March 2016
Radiations, Light And Rays
Infrared Radiation and Light
when a radiant heater or grill is switched on you can detect the infrared radiations coming from it by the heating effects it produces in your skin. in fact all objects emit some infrared because of the motion of their atoms or molecules. most radiate a wide range of wavelengths.
As an object heats up, it radiates more and more infrared and shorter wavelengths. about 700 degree celsius the shortest wavelength radiated can be detected by the eye so the objects glows 'red hot'. above about 1000c the whole of the visible spectrum is covered so the object is 'hot white'.
Short wavelengths infrared is often called 'infrared light' even though it is invisible. however strictly speaking light is just the part of the elctromagnetic spectrum that is visible to the eye.Security alarms and lamps can be switched on by motion sensors that pick up the changing pattern of infarred caused by an approching person.At night,photograps can be taken using infarred.In telephone networks, signals are sent along optical fibers as puless of infarred 'light'.And remote controllers TVs video recoders work by trasmitting infarred puleses.
when a radiant heater or grill is switched on you can detect the infrared radiations coming from it by the heating effects it produces in your skin. in fact all objects emit some infrared because of the motion of their atoms or molecules. most radiate a wide range of wavelengths.
As an object heats up, it radiates more and more infrared and shorter wavelengths. about 700 degree celsius the shortest wavelength radiated can be detected by the eye so the objects glows 'red hot'. above about 1000c the whole of the visible spectrum is covered so the object is 'hot white'.
Short wavelengths infrared is often called 'infrared light' even though it is invisible. however strictly speaking light is just the part of the elctromagnetic spectrum that is visible to the eye.Security alarms and lamps can be switched on by motion sensors that pick up the changing pattern of infarred caused by an approching person.At night,photograps can be taken using infarred.In telephone networks, signals are sent along optical fibers as puless of infarred 'light'.And remote controllers TVs video recoders work by trasmitting infarred puleses.
Saturday, 26 March 2016
Radio waves
Stars are natural images of radio waves. However, radio waves can be produced artificially by making a current oscillate in transmitting aerial (antenna). In a simple radio system a microphone controls the current it to the aerial so that the radio waves 'pulsate'. In the radio receiver, the incoming pulsations control a loudspeaker so that it produces a copy of the original sound. Radio waves are also used to transmit TV pictures.
Tuesday, 22 March 2016
The Lost Symbol
Famed harvard symbologist Robert langdon answers some unexpected summons to appear at the U.S capitol building. His planned lecture is interrupted when a disturbing object is found baring five different symbols. After knowing that his mentor peter solomon is kidnapped, the only way to save him was to obey the commands of his ceptor. To do so langdon has to enter the exotic Masonic world and decrypter an ancient mystical pyramid.There are people to help him along the way. London times has judged it right, this is a book impossible to put down. believe me!
Tuesday, 8 March 2016
What happens when a liquid freezes
In order to melt the ice, thermal energy is needed to break the strong inter-molecular bonds of the water molecules (and hence increase the internal potential energy).
Conversely, when the particles of a liquid come together in freezing, strong bonds are formed. As the strong bonds form, internal potential energy decreases, the thermal energy is released and lost in the surrounding. Since the eternal kinetic energy does not change the temperature does not continue to fall when the liquid is freezing (i.e. during solidification)
The thermal energy that is released during solidification, as the thermal energy absorbed during melting, is called the latent heat of fusion of a substance.
The Science Behind An Air Conditioner
Air are always installed near the ceiling of room to facilitate the setting up the convection currents. An air conditioner releases cool, dry air into the room. The cool air is denser, it sinks. Warm air below, being less dense rises and is drawn into the air conditioner, where it is cooled. In this way, the cool air is circulated and the temperature of the air in the room will eventually drop.
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