A lava lamp is a decorative lamp, invented in 1963 by British entrepreneur Edward Craven Walker, the founder of the lighting company Mathmos.
It consists of a bolus of a special coloured wax mixture inside a glass vessel, the remainder of which contains clear or translucent liquid. The vessel is placed on a base containing an incandescent light bulb whose heat causes temporary reductions in the wax's density and the liquid's surface tension. As the warmed wax rises through the liquid, it cools, loses its buoyancy, and falls back to the bottom of the vessel in a cycle that is visually suggestive of pāhoehoe lava, hence the name. The lamps are designed in a variety of styles and colours.
Lava lamps can be associated with hippie and cannabis cultures. [1] [2]
A classic lava lamp contains a standard incandescent or halogen lamp which heats a tall (often tapered) glass bottle. A formula from a 1968 US patent consisted of water and a transparent, translucent, or opaque mix of mineral oil, paraffin wax, and carbon tetrachloride. [3] p. 2, line 30 The clear water or mineral oil can optionally be coloured with translucent dyes.
Common wax has a density much lower than that of water and would float on top at any temperature. However, carbon tetrachloride is denser than water (also nonflammable and miscible with wax) and is added to the wax to make its density at room temperature slightly higher than that of the water. When heated, the wax mixture becomes less dense than the water, because it expands more than water when both are heated. [3] p. 1, lines 40 & 45 It also becomes fluid, causing blobs of it to ascend to the top of the lamp. There, they cool, increasing their density relative to that of the water, and descend. [3] p. 1, line 47 A metallic wire coil in the bottle's base breaks the cooled blobs' surface tension, allowing them to recombine.
Since 1970, lava lamps made for the US market have not used carbon tetrachloride, the use of which was banned in the country that year due to toxicity. [4] Haggerty, their current manufacturer, has stated that their current formulation is a trade secret. [5]
The underlying fluid mechanics phenomenon in lava lamps is a form of Rayleigh–Taylor instability.
The bulb is normally 25 to 40 watts. It generally takes 45–60 minutes for the wax to warm up enough to form freely rising blobs, when operating the lamp at standard room temperature, and as long as 2 to 3 hours if the room is cooler.
Once the wax is molten, the lamp should not be agitated, or the two fluids may emulsify, and the fluid surrounding the wax blobs will remain cloudy rather than clear. Some recombination will occur as part of the normal cycle of the wax in the container, but the only way to recombine all of the wax is to turn off the lamp and wait for a few hours. The wax then settles back to the bottom, forming one blob once again. Severe cases can require many heating-cooling cycles to clear. [6]
In 2015, a new design was introduced that uses ferrofluid in place of wax. [7]
British entrepreneur Edward Craven Walker had the idea for the lava lamp in 1963 after watching a homemade egg timer, made from a cocktail shaker filled with liquids, as it bubbled on a stovetop in a pub. [8] This precursor was designed and patented GBpatent 703924 by Donald Dunnet. [9] Craven Walker hired British inventor David George Smith to develop the device and the chemical formula it required. Smith is credited as the inventor on the original U.S. patent 3,387,396 for a "Display Device" filed and assigned to Craven-Walker's company in 1965, and subsequently issued in 1968. [3] Craven Walker's company, Crestworth, was based in Poole, Dorset, United Kingdom. He named the lamp "Astro" and had variations such as the "Astro Mini" and the "Astro Coach" lantern.
In 1965, Adolph Wertheimer and Hy Spector were intrigued by Walker's product when they saw it at a German trade show. They bought the American rights and began the Lava Manufacturing Corporation in Chicago to sell what they called the Lava Lite Lamp. In the late 1970s, US rights were sold to Larry Haggerty, who created a subsidiary of his company, Haggerty Enterprises, called Lava World International, which produced American lava lamps for over 30 years. [10]
In 2003, American lava lamp maker Lava World International (formerly Lava-Simplex-Scribe Internationale) moved its production to China. In 2008, it was acquired by Talon Merchant Capital and its name was changed to Lava Lite LLC. As of 2016, lava lamps were being sold under Lifespan brands in North America. [11] In 2018, the "Lava Lamp" brand was acquired by toy and gift maker Schylling Inc. of North Andover, MA. [12] who continue to hold the US trademark rights to both the shape and name of LAVA lamp. [13]
When the American rights were sold, Craven Walker retained the rights for the rest of the world, and took on two business partners in the late 1980s, Cressida Granger and David Mulley. They eventually took over the company and changed its name to Mathmos in 1992. Edward Craven Walker remained a consultant to them until his death in 2000. Mathmos continues to make Lava Lamps and related products. They have won two Queens Awards for Export, and the Best Multi-Media prize at the Design Week awards. [14] [15] Astro lava lamp was launched in 1963 and celebrated its 50th anniversary in 2013. [16] Mathmos lava lamps are still made in the original factory in Poole, Dorset.
Cavitation in fluid mechanics and engineering normally refers to the phenomenon in which the static pressure of a liquid reduces to below the liquid's vapor pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate shock waves that may damage machinery. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal, causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior: inertial cavitation and non-inertial cavitation.
Kerosene, or paraffin, is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from κηρός (kērós) meaning "wax", and was registered as a trademark by Nova Scotia geologist and inventor Abraham Gesner in 1854 before evolving into a generic trademark. It is sometimes spelled kerosine in scientific and industrial usage.
Magma is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles.
Convection is single or multiphase fluid flow that occurs spontaneously through the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity. When the cause of the convection is unspecified, convection due to the effects of thermal expansion and buoyancy can be assumed. Convection may also take place in soft solids or mixtures where particles can flow.
Boiling or ebullition is the rapid phase transition from liquid to gas or vapour; the reverse of boiling is condensation. Boiling occurs when a liquid is heated to its boiling point, so that the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere. Boiling and evaporation are the two main forms of liquid vapourization.
Volcanism, vulcanism, volcanicity, or volcanic activity is the phenomenon where solids, liquids, gases, and their mixtures erupt to the surface of a solid-surface astronomical body such as a planet or a moon. It is caused by the presence of a heat source, usually internally generated, inside the body; the heat is generated by various processes, such as radioactive decay or tidal heating. This heat partially melts solid material in the body or turns material into gas. The mobilized material rises through the body's interior and may break through the solid surface.
Carbon tetrachloride, also known by many other names (such as carbon tet for short and tetrachloromethane, also recognised by the IUPAC), is a chemical compound with the chemical formula CCl4. It is a non-flammable, dense, colourless liquid with a "sweet" chloroform-like odour that can be detected at low levels. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, an anthelmintic and a cleaning agent, but has since been phased out because of environmental and safety concerns. Exposure to high concentrations of carbon tetrachloride can affect the central nervous system and degenerate the liver and kidneys. Prolonged exposure can be fatal.
Spermaceti is a waxy substance found in the head cavities of the sperm whale. Spermaceti is created in the spermaceti organ inside the whale's head. This organ may contain as much as 1,900 litres (500 US gal) of spermaceti. It has been extracted by whalers since the 17th century for human use in cosmetics, textiles, and candles.
Ferrofluid is a liquid that is attracted to the poles of a magnet. It is a colloidal liquid made of nanoscale ferromagnetic or ferrimagnetic particles suspended in a carrier fluid. Each magnetic particle is thoroughly coated with a surfactant to inhibit clumping. Large ferromagnetic particles can be ripped out of the homogeneous colloidal mixture, forming a separate clump of magnetic dust when exposed to strong magnetic fields. The magnetic attraction of tiny nanoparticles is weak enough that the surfactant's Van der Waals force is sufficient to prevent magnetic clumping or agglomeration. Ferrofluids usually do not retain magnetization in the absence of an externally applied field and thus are often classified as "superparamagnets" rather than ferromagnets.
A supercritical fluid (SCF) is a substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. It can effuse through porous solids like a gas, overcoming the mass transfer limitations that slow liquid transport through such materials. SCFs are superior to gases in their ability to dissolve materials like liquids or solids. Near the critical point, small changes in pressure or temperature result in large changes in density, allowing many properties of a supercritical fluid to be "fine-tuned".
Mathmos Limited is a British company that sells lighting products, most famously the lava lamp invented by its founder Edward Craven Walker. It is headquartered in its factory in Poole, Dorset.
Ultrasonic cleaning is a process that uses ultrasound to agitate a fluid, with a cleaning effect. Ultrasonic cleaners come in a variety of sizes, from small desktop units with an internal volume of less than 0.5 litres (0.13 US gal), to large industrial units with volumes approaching 1,000 litres.
In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a viscous magma such that expelled lava violently froths into volcanic ash when pressure is suddenly lowered at the vent. Sometimes a lava plug will block the conduit to the summit, and when this occurs, eruptions are more violent. Explosive eruptions can expel as much as 1,000 kg (2,200 lb) per second of rocks, dust, gas and pyroclastic material, averaged over the duration of eruption, that travels at several hundred meters per second as high as 20 km (12 mi) into the atmosphere. This cloud may subsequently collapse, creating a fast-moving pyroclastic flow of hot volcanic matter.
Edward Craven Walker was a British inventor, who invented the psychedelic Astro lamp, also known as the lava lamp.
Ferrofluidic is the brand name of a staged magnetic liquid rotary sealing mechanism made by the Ferrotec Corporation. Ferrofluidic seals, also known as magnetic liquid rotary seals, are employed in various rotating equipment to facilitate rotary motion while ensuring a hermetic seal. This is achieved through a physical barrier constituted by a ferrofluid, which is held in position by a permanent magnet. Developed in the 1970s, ferrofluidic seals have been utilized in various specialized applications, including computer disk drives, vacuum systems, and nuclear technologies.
A fire extinguisher is a handheld active fire protection device usually filled with a dry or wet chemical used to extinguish or control small fires, often in emergencies. It is not intended for use on an out-of-control fire, such as one which has reached the ceiling, endangers the user, or otherwise requires the equipment, personnel, resources or expertise of a fire brigade. Typically, a fire extinguisher consists of a hand-held cylindrical pressure vessel containing an agent that can be discharged to extinguish a fire. Fire extinguishers manufactured with non-cylindrical pressure vessels also exist, but are less common.
A defoamer or an anti-foaming agent is a chemical additive that reduces and hinders the formation of foam in industrial process liquids. The terms anti-foam agent and defoamer are often used interchangeably. Strictly speaking, defoamers eliminate existing foam and anti-foamers prevent the formation of further foam. Commonly used agents are insoluble oils, polydimethylsiloxanes and other silicones, certain alcohols, stearates and glycols. The additive is used to prevent formation of foam or is added to break a foam already formed.
Cressida Granger is a British entrepreneur. She is the owner and managing director of Mathmos, the lighting company founded by Edward Craven Walker, inventor of the lava lamp.
The liquid droplet radiator (LDR) or previously termed liquid droplet stream radiator is a proposed lightweight radiator for the dissipation of waste heat generated by power plants, propulsion or spacecraft systems in space.
A thermogravitational cycle is a reversible thermodynamic cycle using the gravitational works of weight and buoyancy to respectively compress and expand a working fluid.
The oil, heated by electricity, produces bubbles that slowly ascend through the colored liquid, creating a hypnotic display which is amusing to folks high on mind-expanding drugs.
Hippie accessory invented by Edward Craven Walker in England in 1963, [...] Stoners stare at these blobs for hours at a time, a practice known as 'spacing out.'