Light All About Us (2nd Ed, sound, 1973)

[Music] [Music] [Music] it's all around us almost everywhere we look light light that comes to us in many ways ways to produce light it takes energy energy that can come from [Music] electricity or chemical energy released when something Burns light can also come from nuclear energy released from within the sun we need some kind of energy to produce light because light itself is a form of energy light we know allows us to see things some objects look very bright some look dark how come much light is hitting this rout but it still looks dark dark objects absorb most of the light that hits them all objects absorb some of the light that hits them but some objects absorb less than [Music] others bright shiny objects reflect most of the light that hits them shiny metal we know acts as a mirror what happens when the metal is placed in front of a beam of light directed across a flat [Music] surface as the metal is moved the reflected beam changes Direction but otherwise it changes very [Music] little let's see what happens when we have more than one beam the new beams go off in the same direction as the first what will happen if we bend the metal so the surface is [Music] curved the beams are reflected in different directions let's see what this does to images in the [Music] metal you may have seen mirrors of this sort used in a store to keep an eye on what's Happening what will happen if we bend the metal the other way in instead of [Music] out the reflected light doesn't go outward now the beams go toward one [Music] another what sort of images will we see now you may have seen a magnifying mirror used for putting on [Music] makeup what happens to a sheet of metal when it's [Music] wrinkled it doesn't look so shiny now it's hard to see any image how will it reflect the light beams now not so well the images are scattered materials with rough surfaces scatter light more than materials with smooth surfaces so with a rough object we notice more of the surface than any image reflected in it [Music] some materials let part of the light that hits them pass [Music] through most of the light hitting this material passes through the light is transmitted very little is absorbed or reflected what will happen when we place this in front of the beams of light not surprising such a material is [Music] transparent how will light pass through this transparent [Music] material the beams of light are bent how will things look through [Music] this you you may have seen some glass shaped something like this used as a [Music] magnifier we've seen how light is transmitted by a material with outward curves how will light go through a material with inward curves how will things look through [Music] this [Music] a pie the sort of material light strikes remember affects how light is reflected to our [Music] eyes the sort of material light strikes also affects how light is transmitted to our eyes [Music] you'll be seeing different sources of light and different uses of light all around you see how much you can tell about what happens to light as it interacts with different materials on its way to your [Music] [Music] [Music] eyes [Music]