Lava Lamp
Lava lamps are the latest addition to the world of lamps, contributing to the beautification of the home decoration. Nothing can set the atmosphere of a modern household like a soft glowing lava lamp, placed in perfect position. Nowadays lava lamps are available in different bright and fluorescent colors and add a distinct glamour to the room. These lamps can change color, which in turn changes the effect and shadow play, of your room.
The lamp consists of a base, an illuminating bulb, a glass bottle that contains the ‘lava’ and a top cap. A glass bottle contains an oil and wax each of which has slightly different densities and a metallic wire coil. In lava lamp glass bottle sits on top of the bulb, which heats its contents. The metallic wire coil is hidden in the base of the lamp, on which the glass bottle is placed. The wax used in this is slightly denser than the oil at room temperature, and a little less dense than the oil under marginally warmer conditions. The reason for this is wax expands more than the oil when heated.
At present lava lamps are more decorative than functional. The 40-watt light bulb used in this lamp illuminates the lava goo and the liquid, but not much else. One can use this lava lamp to be a stylish night light in his home, but long term use is not recommended. As the lava lamp becomes warmer, the individual bits of lava goo become frenetic droplets instead of a pleasing slow motion display.
A lava lamp works based on the principal that oil and water do not mix. As the oily and waxy lava base begins to melt from the heat of the light bulb, the resulting convective currents drive the goo upwards. Because the wax and oil in the glass bottle cannot mix with the surrounding water or alcohol, the goo adheres itself in large droplets. When 'lava' in the lava lamp becomes cool, it returns to the bottom. Once the lava lamp is switched off, the wax present in this lamp hardens and traps the mineral oil. The water or alcohol remains clear because no ingredients mixed with it. There are recipes available in science experiment books and on the Internet to make a homemade lava lamp. In homemade lava lamp we can use candle wax and mineral oil with a form of carbon tetrachloride, which is available at a local dry cleaner's shop. The glass base used in this is filled with either colored water or a mixture of alcohols.