Transparent, translucent, opaque

Ghulan, Sheeta and Sara are playing hide and seek. Ghulan hides behind a wall. Sheeta hides behind a big tree. Sara hides behind a frosted glass door, which has a hazy surface. Sheeta's younger brother watches it all through the glass window of his house.

Transparent: things can be seen clearly through them. Glass, water, air and cellophane paper are transparent; so are a glass tumbler and window glass. That is how Sheeta's brother sees everything. A camera lens and a phone's screen guard are transparent too.

Opaque: you cannot see through them at all. Wood, cardboard and metals are opaque; so are a wooden board and an eraser. Hold a box in front of your hand and nobody can count your fingers. The wall and the tree trunk are opaque, which is why Ghulan and Sheeta hid behind them. If the window were a closed wooden one, her brother could not see them.

Translucent: you can see through them, but not clearly. Butter paper and frosted glass are translucent. Behind the frosted door, Sara is only a hazy shape.

Careful: wood is opaque and glass is transparent. So "wood is translucent while glass is opaque" is false. And air between us is transparent, while a wooden door between us is opaque.