4.5 Transparent, Translucent and Opaque Materials

1) Depending on whether light can pass through them, materials can be
    classified into 3 groups:
    (a) Transparent materials
    (b) Translucent materials
    (c) Opaque materials
___________________________________________________________

2) Transparent materials allow the most light to pass through.
    (a) Transparent materials can be made of clear glass or clear
          plastic.
    (b) Objects behind a transparent material can be seen clearly.
    (c) Examples: glass, bottle, transparency sheet, light bulb, thermometer,
         beaker, ice, spectacles.
  

                      Windsreen                                                                   Aquarium
___________________________________________________________________

3) Translucent materials allow only some light to pass through.
    (a) Examples of translucent materials are tracing paper, frosted glass
          and certain types of plastic and thin cloth.
    (b) Objects behind a translucent material cannot be seen clearly and
          appeared blurred.
    (c) Othe examples: coloured glass bottle, window pane, plastic bag,
          plastic container.

                                       Frosted glass                                      Lampshade
__________________________________________________________________

4) Opaque materials do not allow any light to pass through.
    (a) A shadow forms behind an opaque material when a light shines
         on it.
    (b) Objects behind an opaque material cannot be seen at all.
    (c) Wood, rubber, metals, some plastics and cloth are opaque materials.
    (d) Examples: wall, hat, clothes, towel, box, paper, bag, book.

                              Umbrella                                                   Wooden door