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
(b) Objects behind a transparent material can be seen clearly.
(c) Examples: glass, bottle, transparency sheet, light bulb, thermometer,
beaker, ice, spectacles.
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
(c) Othe examples: coloured glass bottle, window pane, plastic bag,
4) Opaque materials do not allow any light to pass through.
(a) A shadow forms behind an opaque material when a light shines
(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.