Hockenbury Discovering Psychology 5th txtbk

Vision93Visible lightInvisible long wavesInvisible short wavesACcircuitsRadioTVCellphonesUltravioletMicrowaves InfraredraysX-raysGammaraysCosmicraysAmplitudeWavelength750700600 500 400 350Red Yellow Green Blue-violetWavelengths in nanometers (billionths of a meter)Figure 3.2 The Electromagnetic Spectrum We are surrounded by different kinds of electromagneticenergy waves, yet we are able to see only a tiny portion of the entire spectrum of electromagnetic energy.Some electronic instruments, like radio and tele vision, are specialized receivers that detect a specificwavelength range. Similarly, the human eye is sensitive to a specific and very narrow range ofwavelengths.What We SeeThe Nature of LightLight is just one of many different kinds of electromagnetic energy that travel in theform of waves. Other forms of electromagnetic energy include X-rays, the micro -waves you use to pop popcorn, and the infrared signals or radio waves transmitted byyour TV’s remote control. The various types of electromagnetic energy differ inwavelength, which is the distance from one wave peak to another.Humans are capable of seeing only a minuscule portion of the electromagneticenergy range. In Figure 3.2, notice that the visible portion of the electromagneticenergy spectrum can be further divided into different wavelengths. As we’ll discussin more detail later, the different wavelengths of visible light correspond to ourpsychological perception of different colors.How a Pit Viper Sees a Mouse at NightDoes the world look different to otherspecies? In many cases, yes. Each specieshas evolved a unique set of sensory capa -bilities. Pit vipers see infrared light, whichwe sense only as warmth. The mouse herehas been photographed through an in fraredviewer. The image shows how a pitviper uses its infrared “vision” to detectwarm-blooded prey at night (Safer &Grace, 2004). Similarly, many insect andbird species can detect ultraviolet light,which is invisible to humans.wavelengthThe distance from one wave peak toanother.