Classify the objects or materials given below as opaque, transparent or translucent and luminous or non-luminous:
Air, water, a piece of rock, a sheet of aluminum, a mirror, a wooden board, a sheet of polythene, a CD, smoke, a sheet of plane glass, fog, a piece of red hot iron, an umbrella, a lighted fluorescent tube, a wall, a sheet of carbon paper, the flame of a gas burner, a sheet of cardboard, a lighted torch, a sheet of cellophane, a wire mesh, kerosene stove, sun, firefly, moon.
Classification of objects is given below:
| Object | Transparent/Translucent /Opaque | Luminous/ Non-luminous | 
| Air | Transparent | Non-luminous | 
| Water | Transparent | Non-luminous | 
| A Piece of rock | Opaque | Non-luminous | 
| A sheet of aluminum | Opaque | Non-luminous | 
| Mirror | Opaque | Non-luminous | 
| A wooden board | Opaque | Non-luminous | 
| A sheet of polythene | Translucent | Non-luminous | 
| CD | Opaque | |
| Smoke | Translucent | Non-luminous | 
| Sheet of plane glass | Transparent | Non-luminous | 
| Fog | Translucent | Non-luminous | 
| Piece of red hot iron | Opaque | Luminous | 
| Umbrella | Opaque | Non-luminous | 
| Lighted fluorescent tube | Opaque | Luminous | 
| Wall | Opaque | Non-luminous | 
| Sheet of carbon paper | Opaque | Non-luminous | 
| Flame of a gas burner | Translucent | Luminous | 
| Sheet of cardboard | Opaque | Non-luminous | 
| Lighted torch | Opaque | Luminous | 
| Sheet of cellophane | Transparent | Non-luminous | 
| Wire mesh | Translucent | Non-luminous | 
| Kerosene stove | Opaque | Luminous | 
| Sun | Opaque | Luminous | 
| Moon | Opaque | Non-luminous | 
| Fire fly | Opaque | Luminous |