Although Craven Walker is not a well known name, we all have heard of his invention. It started in the 50's back when Craven was having a drink in a pub in England and that's when his light bulb lit up, and he invented what was to be know as the lava lamp.

Craven Walker got his idea from some little fascinating lamp which Walker described as a "contraption made out of a cocktail shaker, old tins and things." It was what was to become the starting point and light bulb for Walker's design. Walker proceeded to purchase the original liquid-filled lamp. Walker had insisted to build a better and more practical version of the original one that the late Mr.Dunnett had created and he spent the next 15 years doing it. Walker worked with his little company The Crestworth Company of Dorset, England to create his lamp. At first the local store owners thought that Walker's lamps were ugly and disgusting. Luckily for him the "Psychedelic Movement" and the "Love Generation" came to dominate 60's merchandising. The sales of the lava lamp boomed. It was the ideal lamp for the modern times. Walker declared, "If you buy my lamp. you won't need to buy drugs."

There are three main parts to the Lava lamp: There is the Base which holds a 40 watt frosted appliance light bulb inside a reflector cone. This cone rests on a second cone which houses the light bulb socket and electrical cord connection. The electrical cord is about 2m in length and has a small switch on it. The cord plug is a standard US 120v plug. Next there is the lamp which is a glass container containing two fluids, called water and lava. The exact nature of these two fluids is a trade secret of Haggerty Enterprises. The top of the Lamp is sealed with a metal cap that looks very much like a soda bottle cap. There is a small amount of air at the very top of the Lamp. Loose at the bottom of the Lamp is a small coil of wire called the element. The last is the Cap, a small plastic cover over the top of the Lamp which serves to both hide the Lamp's cap and waterline. When cold, the lava is a hard lump at the bottom of the lamp. Because the Bulb is sitting on the Base, the top of the light bulb can barely be seen from the side. When the light bulb in the Base is turned on, it heats both the element and the lava. Warm lava is less dense than the water and rises to the top. Farther away from the heat of the element and light bulb, the lava cools and becomes more dense than the water whereupon it falls. The falling lava rejoins the lava at the bottom which is attached to the element. Both the element and the light bulb reheat the lava and it begins to rise all over again. This is the primary action of the Lava lamp. Lava lamps require a warm-up period of about 30 minutes to melt the lava before they go into full motion. During this warm-up period, the Lava lamp remains somewhat static except brief periods of eruptions of hot lava working its way up the side of the Lamp or through the middle of the solid lava dome at the base. A typical first eruption, the lava becomes partially separated from the heat of the light bulb and element and cools .Typically the Lava lamp remains in this state for a few minutes until the light bulb and element are again able to melt the lava.

After Walker's little invention became a hit two entrepreneurs from America, got rights to sell the lamp in the US and renamed it lava lite lamp. Now they still produce over 400,000 lava lite lamps a year, and are still a big hit.

Another site where I found info.

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