Bits are Not just for Numbers or Characters Computers store characters as bits or binary digits Characters from the English language keyboard can be represented in ASCII as a series of 7 bits This includes letters numbers and special characters Unicode the common coding system because it expands the possible character set All Internet operations use Unicode Computers perform arithmetic in binary base 2 rather than decimal base 10 101 10 111 Copyright 2009 by Helene G Kershner 1100 10 10 10 1111 10 Bits are Not just for Characters The World of computers is filled with more than characters and binary numbers What else is it filled with Color Pictures Sound Copyright 2009 by Helene G Kershner Bits are Not just for Characters All computer data is represented using bits Bits can only have two states on off 0 1 black white color on color off Everything is made up of bits numbers letters symbols pictures videos sound music Copyright 2009 by Helene G Kershner Bits are Not just for Characters Screen images Whether we display text or graphics on the screen all are created as a series of closely placed dots of light A pixel is a dot of light on a computer screen Pixel is short for picture element Resolution is a measure of pixel density on a screen Copyright 2009 by Helene G Kershner Bits are Not just for Characters Resolution is a measure of pixel density on a screen The more pixels per square inch the higher the resolution of a screen image and the clearer and crisper it appears A traditional monitor displays an image made up of 1024 columns and 786 rows of pixels This is a pixel density or 1024 x 768 or 786 432 lighted dots Copyright 2009 by Helene G Kershner Bits are Not just for Characters Images Black and white TV and early computer monitors used lighted pixels of a single color to produce Characters images Early computer monitors were not necessarily black and white Today the world is in color Well sort of Copyright 2009 by Helene G Kershner Bits are Not just for Characters The human eye see images and colors based on the sensitivity of cells in the retina of the eye to different wavelengths of light The retina contains three types of color receptors cells or cones The brain interprets the information transmitted by the eye into images If you are color blind some part of the message between the eye and the brain doesn t work properly This can be caused by eye or brain dysfunction It is often related to a lack of certain cone chemicals in the eye Human vision color or black white is based on the wavelengths of light reflected off objects In the physical world color is ANALOG http en wikipedia org wiki Color Copyright 2009 by Helene G Kershner Bits are Not just for Characters Images When displaying graphics picture and images a technique called gray scaling is used This is much like a black and white photograph where colors are represented not as pure black and white but rather as shades of gray Grayscale images vary from black at the weakest intensity to white at the strongest though in principle the samples could be displayed as shades of any color Grayscale is NOT black and white which would be only those colors http en wikipedia org wiki Grayscale Copyright 2009 by Helene G Kershner Bits are Not just for Characters Images Color Most color monitors use a red green blue RGB format When these three colors of light are mixed white light is produced A wide range of colors can be obtained by mixing these three colors http en wikipedia org wiki RGB color model Copyright 2009 by Helene G Kershner Bits are Not just for Characters Images Color Color requires independent integrated hardware to light the different colored pixels in the desired combinations Keeping track of and controlling the more complex hardware requires a color graphics card manage to he pixels All of this management requires additional dedicated memory Copyright 2009 by Helene G Kershner Bits are Not just for Characters Images RGB The specific color that a pixel describes is some blend of three colors of light red green blue Up to three bytes 8 bits each of data can be used to specifying a pixel s color 1 One byte for each major color component A true color or 24 bit color system uses all three bytes Many color monitors use only one byte 8 bits for each pixel limiting the monitor to only 256 28 different colors 2 1 A definition from Whatis com 2 http www webopedia com TERM P pixel html Copyright 2009 by Helene G Kershner Bits are Not just for Characters Images Copyright 2009 by Helene G Kershner Bits are Not just for Characters Images grayscale true color http en wikipedia org wiki Bits per pixel Copyright 2009 by Helene G Kershner Bits are Not just for Characters Images Here the pixels are visible to the eye http www youtube com watch v m0S0qg4Zh7Y Here the pixels are essentially invisible http www youtube com watch v avMW hKtcDM Copyright 2009 by Helene G Kershner Bits are Not just for Characters Sound What is sound Sound is vibration transmitted through a solid liquid or gas Sound in humans is those vibrations capable of being detected by the ear and interpreted by the brain 1 Sound is a wave Sound waves move through the air Sound waves move through other materials Sound in animals is physiologically the same it is heard by the ear and interpreted by the brain but most animals hear a larger range of sound waves than human http en wikipedia org wiki Sound Copyright 2009 by Helene G Kershner Bits are Not just for Characters Sound Sound is vibration Sound is a wave Sound is Analog The sound of our voice is the vibration made by our vocal chords A door moving back and forth The wind A musical instrument Vibrating wire Vibrating reed Vibrating lips A dog whistle that humans cannot hear The whistle is still vibrating If a tree falls in the forest and no one is there to see it fall does it make a sound http en wikipedia org wiki Sound Copyright 2009 by Helene G Kershner Bits are Not just for Characters Sound Sound is vibration Sound is a wave Sound is Analog http www youtube com watch v VEiEBEadZFI featur e PlayList p 448A499C6D44B935 index 6 http www youtube com watch v q19p1df2tWE feature r elated Copyright 2009 by Helene G Kershner Bits are Not just for Characters Sound What is a sound wave It s a wave of sound Music is just a bunch of sound waves arranged in a nice pattern www globalsecurity org ship acoustics htm Copyright 2009 by Helene G Kershner http library thinkquest org 06aug 02101 physics soundwaves htm Bits are