Stupid Question ™
Aug. 9, 2004
By John Ruch
© 2004
Q: If people keep batteries in the fridge to keep them fresh, why is it bad for car batteries to be out in the cold?
—Frosty, Chicago, Illinois
A: We’re talking about different kinds of batteries kept at different temperatures for different reasons.
There’s actually no need to keep modern batteries in the refrigerator. And back when it may have been a good idea, the concept was to warm them up again to room temperature before using them—something hard to do with a car battery. The same cold that prevents energy from leaking out of a battery also prevents us from extracting it for our own devices.
Batteries slowly discharge tiny amounts of energy even when they’re just lying around, until they finally die. (This is called “self-discharge” or “local action.”) Temperature can quicken or hinder that process, since heat is a key ingredient of the chemical reactions inside a battery.
The point of storing old-style batteries into the refrigerator was to cool them and slow down the chemical reactions, thus slowing down the energy leakage and extending the batteries’ shelf life.
The chill of a winter night (well below your refrigerator’s comfy 45 degrees or so) will similarly extend your car battery’s life, but that’s a negligible benefit. Self-discharge is not the winter problem with car batteries.
A brief primer on batteries: A battery is a series of chemical cells that store energy for later release. The basic elements of a cell are a substance that emits electrons during a chemical reaction (the cathode); a substance that picks up electrons (the anode); and a substance that triggers or serves as the medium for a chemical reaction (the electrolyte). The cathode, anode and electrolyte can be made of a variety of substances, usually some type of metal.
By sticking the battery into an electronic circuit (like any battery-operated machine), we can pull electricity out of it.
The typical car battery is a lead-acid battery. Its cathodes are plates of lead and its anodes are lead dioxide, with water-diluted sulfuric acid as the electrolyte.
Lead-acid batteries have a very high self-discharge rate and usually die within a few years, even though they are quite large. They are also very temperature-sensitive. Their typical peak efficiency temperature is around 75 degrees Fahrenheit. At temperatures in the 100-degree range, the batteries will start self-discharging at even higher rates.
But lead-acid batteries don’t work well in cooler temperatures, either. The electrolyte thickens up and electrons don’t flow as smoothly (in fact, it can actually freeze entirely, damaging the battery). The energy capacity drops sharply when you get around the zero-degree mark. In below-zero temperatures, a car battery will often produce less than half its normal electrical current.
That’s a special problem because car batteries are a special type of lead-acid battery. They are designed to provide a single quick burst of energy to start the motor, and then get recharged by the alternator. There is rarely enough juice for more than a couple more tries. On a cold winter day, when the battery’s capacity has plunged, you may get only one or two cranks before the battery dies—or it might not produce enough juice to start the motor at all.
The first generation of household batteries for flashlights and whatnot did have a fairly short shelf-life due to self-discharge. These so-called zinc-carbon batteries may have benefited from refrigeration, though the self-discharge really sped up at temperatures of about 100 degrees and higher. Like a car battery, their capacity also plunged at low temperatures (below 50 degrees or so) but a quick warming with the hands would fix that.
The standard household battery today has a manganese dioxide cathode, a zinc anode and water-diluted potassium hydroxide as an electrolyte. It operates well under a very wide temperature range, from about 0 to 130 degrees. And even at room temperature, its self-discharge rate is very low. I have a pack of Energizers laying around the house that boasts a 2010 expiration date.
Refrigerating such batteries would undoubtedly lengthen their shelf life by slowing self-discharge, but probably to a negligible degree due to the stability of its materials. No major battery manufacturer recommends refrigerating household batteries; they merely suggest keeping them dry and at room temperature.
Batteries based on lithium operate well in truly incredible temperature extremes, from 40 below zero to 150 degrees. And they have very little self-discharge because of lithium’s tendency to develop an inert, oxidized surface when the battery isn’t being used. Temperature hardly affects that miniscule self-discharge one way or the other.
Showing posts with label physics. Show all posts
Showing posts with label physics. Show all posts
March 29, 2008
March 28, 2008
Perpetual Motion
By John Ruch
© 2003
Q: Why don’t perpetual motion machines work, and why do people still believe in them?
—G.O.
A: The simple answer is that perpetual motion machines are impossible because they violate the first and second laws of thermodynamics.
This isn’t just dogma. The thermodynamic laws were largely written by the failure of perpetual motion attempts.
What alchemy was to chemistry, what astrology was to astronomy, perpetual motion was to mechanics. (A perpetual motion puzzle also led to the engineering principle of virtual work.)
Almost all perpetual motion machines have existed only as thought experiments on paper. Those actually built and tested have failed or have been exposed as frauds.
A perpetual motion machine is essentially a machine that will run under its own power, and only its own power, forever. More typically, it is also proposed to output enough excess energy to do useful work.
A classic early model was a pump or screw that would lift water, which would then power a turbine that operated the pump/screw.
Another, and the one most frequently built, was an overbalanced wheel with weights hanging off it on jointed arms, or with chambers inside containing small weights. The (wrong) idea is that the wheel, given a push, will spin forever as the weights fall on one side and rise on the other.
There are endless other varieties based on nearly every known physics principle. Generally, thermodynamics aside, they are based on misunderstandings and miscalculations of the machine system’s forces.
“Free energy” machines supposedly driven by an unknown force of nature are the modern euphemism for perpetual motion.
The first law of thermodynamics notes that energy cannot be created or destroyed, merely transferred. Thus, a machine’s energy output cannot exceed its input.
The second law notes that friction makes perfect mechanical efficiency impossible, so the energy output cannot even equal the input. And the waste heat given off by a machine cannot be fed back into it to do work without the addition of outside energy to the system.
Thus, a machine can’t run itself by itself, produce more energy than goes into it, and/or run forever.
Many “free energy” scammers claim their machines will run “until the parts wear out.” Of course, parts wear out due to friction and other heat-wasting forces, which are part of what makes perpetual motion impossible.
Perpetual motion today is largely a scam that exploits existing beliefs such as anti-government paranoia or environmentalism—and the hunger for a free lunch.
The idea first took root in early medieval Europe, where water-driven mills were economically important, then bloomed in the mechanically-inclined Renaissance. Leonardo da Vinci dabbled in it before concluding it was “among the excessive and impossible beliefs of man.”
On a cultural level, authors of that era made analogies to the alchemical idea of creating a self-perpetuating miniature world (a “microcosm”), or the legends of “perpetual lamps” supposedly found burning in ancient tombs.
The idea became a widespread mania in the mid-1800s, perhaps a natural response to the industrial revolution. It fed on the later discovery of radioactivity, which to some looked like “free energy.”
© 2003
Q: Why don’t perpetual motion machines work, and why do people still believe in them?
—G.O.
A: The simple answer is that perpetual motion machines are impossible because they violate the first and second laws of thermodynamics.
This isn’t just dogma. The thermodynamic laws were largely written by the failure of perpetual motion attempts.
What alchemy was to chemistry, what astrology was to astronomy, perpetual motion was to mechanics. (A perpetual motion puzzle also led to the engineering principle of virtual work.)
Almost all perpetual motion machines have existed only as thought experiments on paper. Those actually built and tested have failed or have been exposed as frauds.
A perpetual motion machine is essentially a machine that will run under its own power, and only its own power, forever. More typically, it is also proposed to output enough excess energy to do useful work.
A classic early model was a pump or screw that would lift water, which would then power a turbine that operated the pump/screw.
Another, and the one most frequently built, was an overbalanced wheel with weights hanging off it on jointed arms, or with chambers inside containing small weights. The (wrong) idea is that the wheel, given a push, will spin forever as the weights fall on one side and rise on the other.
There are endless other varieties based on nearly every known physics principle. Generally, thermodynamics aside, they are based on misunderstandings and miscalculations of the machine system’s forces.
“Free energy” machines supposedly driven by an unknown force of nature are the modern euphemism for perpetual motion.
The first law of thermodynamics notes that energy cannot be created or destroyed, merely transferred. Thus, a machine’s energy output cannot exceed its input.
The second law notes that friction makes perfect mechanical efficiency impossible, so the energy output cannot even equal the input. And the waste heat given off by a machine cannot be fed back into it to do work without the addition of outside energy to the system.
Thus, a machine can’t run itself by itself, produce more energy than goes into it, and/or run forever.
Many “free energy” scammers claim their machines will run “until the parts wear out.” Of course, parts wear out due to friction and other heat-wasting forces, which are part of what makes perpetual motion impossible.
Perpetual motion today is largely a scam that exploits existing beliefs such as anti-government paranoia or environmentalism—and the hunger for a free lunch.
The idea first took root in early medieval Europe, where water-driven mills were economically important, then bloomed in the mechanically-inclined Renaissance. Leonardo da Vinci dabbled in it before concluding it was “among the excessive and impossible beliefs of man.”
On a cultural level, authors of that era made analogies to the alchemical idea of creating a self-perpetuating miniature world (a “microcosm”), or the legends of “perpetual lamps” supposedly found burning in ancient tombs.
The idea became a widespread mania in the mid-1800s, perhaps a natural response to the industrial revolution. It fed on the later discovery of radioactivity, which to some looked like “free energy.”
Singing Sand
Stupid Question ™
Feb. 27, 2003
By John Ruch
© 2003
Q: What is “singing sand” and does it actually make music?
—A.S.
A: “Singing sands” are a really neat natural mystery: relatively easy to experience first-hand and with a basic mechanism that is obvious, yet still baffling.
Singing sands make strange noises when disturbed. “Singing” is romantic; really they can be divided into squeakers and boomers.
Squeakers emit a short, sharp, single-frequency sound when stepped on or poked, with some sounding like a dog bark or frog ribbit. I experienced this first-hand on a Cape Cod beach that emitted a mild squeak as though walking in icy snow.
Boomers create a truly astonishing, and at times deafening, roar when they avalanche down the sides of sand dunes (whether blown down by wind or pushed by a human hand). It’s a complex, multiple-frequency sound that can be heard for miles.
Boomer recordings have a resonant bass sound with clear harmonics and a steady underlying beat. The most accurate comparisons are to a propeller airplane or a gigantic didgeridoo, the Australian aboriginal wind instrument.
Squeakers are apparently much more common than boomers, though this may be a matter of geography: squeakers are exclusively a beach phenomenon, while boomers are almost exclusively a desert phenomenon. Obviously, beaches get more visitors than deserts.
Dozens of squeaker sites are known around the world, with the most famous being Singing Beach near Manchester, Massachusetts and the shores of Lake Michigan and of the Scottish Isle of Eigg (all the subjects of the earliest scientific reports). In all cases, squeaking sand is visually indiscernible from regular, silent sand.
Boomer dunes are known in nearly every sandy desert area of the world. The most famous are Sand Mountain near Fallon, Nevada; “Jebel Nakus,” a large dune in the Sinai desert; and the Hill of Sounding Sand in Dunhuang, China.
“Singing sands” are almost always silica-based, but the “Barking Dunes” of the Hawaiian island of Kauai are calcium carbonate and are the only boomers known outside of deserts. (They’re now overgrown and no longer boom.)
Nobody knows what’s behind the sounds, or if booms and squeaks are even related. Most boomers will emit squeaks if rapidly compressed in lab experiments, but at multiple frequencies.
Clearly, friction between sand grains is key, but the sound seems out of all proportion to the rubbing. Squeakers tend to have highly spherical, very uniform grains that probably compress in a unique way. Boomers, on the other hand, are often bumpy and irregular, but extremely smooth. The mechanics of sand avalanches are poorly understood, compounding the mystery.
Moisture is also key. Even slight atmospheric humidity will utterly kill a boomer’s boom. Squeakers must also be dry, but are best if they have recently been wetted and dried out. They are rarely found farther than 100 feet from a shoreline.
Another oddity is that if you take a bag of singing sand home, it will delight you with sounds for only a few weeks before going silent. But it can usually be revived: boomers by baking in an oven, and squeakers by washing and drying.
Feb. 27, 2003
By John Ruch
© 2003
Q: What is “singing sand” and does it actually make music?
—A.S.
A: “Singing sands” are a really neat natural mystery: relatively easy to experience first-hand and with a basic mechanism that is obvious, yet still baffling.
Singing sands make strange noises when disturbed. “Singing” is romantic; really they can be divided into squeakers and boomers.
Squeakers emit a short, sharp, single-frequency sound when stepped on or poked, with some sounding like a dog bark or frog ribbit. I experienced this first-hand on a Cape Cod beach that emitted a mild squeak as though walking in icy snow.
Boomers create a truly astonishing, and at times deafening, roar when they avalanche down the sides of sand dunes (whether blown down by wind or pushed by a human hand). It’s a complex, multiple-frequency sound that can be heard for miles.
Boomer recordings have a resonant bass sound with clear harmonics and a steady underlying beat. The most accurate comparisons are to a propeller airplane or a gigantic didgeridoo, the Australian aboriginal wind instrument.
Squeakers are apparently much more common than boomers, though this may be a matter of geography: squeakers are exclusively a beach phenomenon, while boomers are almost exclusively a desert phenomenon. Obviously, beaches get more visitors than deserts.
Dozens of squeaker sites are known around the world, with the most famous being Singing Beach near Manchester, Massachusetts and the shores of Lake Michigan and of the Scottish Isle of Eigg (all the subjects of the earliest scientific reports). In all cases, squeaking sand is visually indiscernible from regular, silent sand.
Boomer dunes are known in nearly every sandy desert area of the world. The most famous are Sand Mountain near Fallon, Nevada; “Jebel Nakus,” a large dune in the Sinai desert; and the Hill of Sounding Sand in Dunhuang, China.
“Singing sands” are almost always silica-based, but the “Barking Dunes” of the Hawaiian island of Kauai are calcium carbonate and are the only boomers known outside of deserts. (They’re now overgrown and no longer boom.)
Nobody knows what’s behind the sounds, or if booms and squeaks are even related. Most boomers will emit squeaks if rapidly compressed in lab experiments, but at multiple frequencies.
Clearly, friction between sand grains is key, but the sound seems out of all proportion to the rubbing. Squeakers tend to have highly spherical, very uniform grains that probably compress in a unique way. Boomers, on the other hand, are often bumpy and irregular, but extremely smooth. The mechanics of sand avalanches are poorly understood, compounding the mystery.
Moisture is also key. Even slight atmospheric humidity will utterly kill a boomer’s boom. Squeakers must also be dry, but are best if they have recently been wetted and dried out. They are rarely found farther than 100 feet from a shoreline.
Another oddity is that if you take a bag of singing sand home, it will delight you with sounds for only a few weeks before going silent. But it can usually be revived: boomers by baking in an oven, and squeakers by washing and drying.
Aurora Audibility
Stupid Question ™
Nov. 28, 2002
By John Ruch
© 2002
Q: Is it true you can hear the aurora?
—A.S.
A: There are hundreds of reports going back to Roman times of the aurora borealis (or Northern Lights) producing sounds. (I could find no reports for the less-seen Southern Lights.) The idea is also part of Inuit (Eskimo) folklore.
The problem: aurorae occur at 35 to 600 miles up, so far away and in such thin air that they would transmit no audible sounds to the ground if they made any, which they don’t.
Also, while a few supposed recordings have been made, none has been definitively shown to be anything except background noise.
So either people are mistaken or nature has something new to teach us. (And not just about aurorae—similar sounds have been reported with brightly glowing meteors.)
Aurorae are writhing, pulsing areas of light in the sky centered on the magnetic poles. They are produced when charged particles blown off the Sun are trapped in the Earth’s magnetic field and ionize air molecules, causing them to glow.
Ionization is basically an electrical phenomenon, so it’s interesting that reported auroral sounds resemble electronic static: hissing, crackling, ringing, swishing, whistling, rustling like tissue paper or cellophane.
Reports of sound are rare, even among people who have seen aurorae multiple times. Typically, the sound is said to rise and fall in unison with changes in the aurora’s intensity, and to occur simultaneously with it.
Also common is for only one person in a group to hear any sound. The Royal Astronomical Society of Canada in 1928 reported an unscientific test in which members of a government survey team blindfolded one of their fellows who said he could hear an aurora; he reportedly accurately identified changes in its brightness by ear.
Some claims strain credibility. One advanced by the great scientist Antoine Henri Becquerel claimed the sound came with a sulfurous smell.
The sound could be an illusion or wishful thinking. It could be tinnitus only noticed while quietly watching the aurora, or it could be sound of freezing breath moisture, cracking ice or crunching snow.
Aurorae do produce very low frequency radio waves that, if run through a radio amplifier, make whistles and crackles similar to some of the sound reports. (I have heard recordings of this radio noise and it is eerie.) One theory is that something in nature, even in the human body, picks up these waves and turns them into sound. What and how are unknown.
Aurorae also increase the general electric charge of the air at ground level, though minutely. Some speculate that this causes miniature sparks that create the sound. But surely some of these sparks would be visible, and they have never been reported.
According to extremely rare reports that are anomalies within an anomaly (and pure scientific heresy), the distance of the aurorae isn’t always a problem. They claim seeing aurorae dipping to just a few thousand feet, or even ground level, with the observer walking through a glowing white fog filled with flashing colors, while the auroral sound crackles all around.
Nov. 28, 2002
By John Ruch
© 2002
Q: Is it true you can hear the aurora?
—A.S.
A: There are hundreds of reports going back to Roman times of the aurora borealis (or Northern Lights) producing sounds. (I could find no reports for the less-seen Southern Lights.) The idea is also part of Inuit (Eskimo) folklore.
The problem: aurorae occur at 35 to 600 miles up, so far away and in such thin air that they would transmit no audible sounds to the ground if they made any, which they don’t.
Also, while a few supposed recordings have been made, none has been definitively shown to be anything except background noise.
So either people are mistaken or nature has something new to teach us. (And not just about aurorae—similar sounds have been reported with brightly glowing meteors.)
Aurorae are writhing, pulsing areas of light in the sky centered on the magnetic poles. They are produced when charged particles blown off the Sun are trapped in the Earth’s magnetic field and ionize air molecules, causing them to glow.
Ionization is basically an electrical phenomenon, so it’s interesting that reported auroral sounds resemble electronic static: hissing, crackling, ringing, swishing, whistling, rustling like tissue paper or cellophane.
Reports of sound are rare, even among people who have seen aurorae multiple times. Typically, the sound is said to rise and fall in unison with changes in the aurora’s intensity, and to occur simultaneously with it.
Also common is for only one person in a group to hear any sound. The Royal Astronomical Society of Canada in 1928 reported an unscientific test in which members of a government survey team blindfolded one of their fellows who said he could hear an aurora; he reportedly accurately identified changes in its brightness by ear.
Some claims strain credibility. One advanced by the great scientist Antoine Henri Becquerel claimed the sound came with a sulfurous smell.
The sound could be an illusion or wishful thinking. It could be tinnitus only noticed while quietly watching the aurora, or it could be sound of freezing breath moisture, cracking ice or crunching snow.
Aurorae do produce very low frequency radio waves that, if run through a radio amplifier, make whistles and crackles similar to some of the sound reports. (I have heard recordings of this radio noise and it is eerie.) One theory is that something in nature, even in the human body, picks up these waves and turns them into sound. What and how are unknown.
Aurorae also increase the general electric charge of the air at ground level, though minutely. Some speculate that this causes miniature sparks that create the sound. But surely some of these sparks would be visible, and they have never been reported.
According to extremely rare reports that are anomalies within an anomaly (and pure scientific heresy), the distance of the aurorae isn’t always a problem. They claim seeing aurorae dipping to just a few thousand feet, or even ground level, with the observer walking through a glowing white fog filled with flashing colors, while the auroral sound crackles all around.
No Reverse Microwave
Stupid Question ™
July 5, 2001
By John Ruch
© 2001
Q: Why isn’t there a reverse microwave oven to cool food quickly?
—J.D.
A: Microwave ovens heat food invisibly and quickly, without raising the air temperature in the oven. It seems like magic, so why not just reverse the spell and start flash-freezing?
The problem is that microwaves are energy in electromagnetic form. In the oven, they heat food by adding their energy to it. Cooling food requires the removal of energy, not the addition of it.
Like light and radio waves, microwaves are electromagnetic waves, but they’re of especially high frequency and wavelength. They pass easily through air and bounce harmlessly off metal and most plastics, glass and ceramics. They are extremely useful in radar and telecommunications.
They can also heat food—as long as the food contains water. (Pure oil, for example, won’t heat up in a microwave.) Within a particular frequency range, the cycling of their electromagnetic fields causes water molecules (which are electrically polarized, with a negative charge at one end and a positive charge at the other) to flip back and forth. This constant flipping makes the water molecules rub against each other very rapidly, turning the microwaves’ energy into frictional heat.
The frequency of almost all home microwave ovens is 2.45 gigahertz, which means the water molecules flip at a rate of 2.45 billion times per second. That makes for mighty fast heating. And because the microwaves penetrate all parts of the food item simultaneously, the whole thing is cooked all at once (as opposed to conventional ovens, which use hot air to cook from the outside in).
Microwave ovens are also highly energy-efficient. About 50 percent of the power required to run them goes directly into cooking, compared with only about 10 percent for conventional ovens.
Refrigeration, on the other hand, remains a difficult and relatively inefficient process. Flash-freezers are available, but they use expensive coolants and probably don’t have enough household utility to be worth it.
The problem is that energy can’t be destroyed, only moved to another place or turned into another form. It takes a lot of work to remove that energy and keep it out.
Home refrigerators and freezers work on the principle that fluids (typically Freon or a similar substance) absorb heat as they change state from liquid to gas, thus lowering the temperature of nearby objects. A gas is compressed and forced into a condenser, where it cools and liquefies, then flows into coils inside the walls of the refrigerator. Inside these coils, it vaporizes, which draws heat from the whatever’s inside the fridge. It then rises back to the compressor.
Like the conventional oven, this process ultimately is moving heat through the air. It’s hard, expensive work. Unfortunately, there is no known “cold ray” to replace it, and it’s hard to imagine how there could be one.
July 5, 2001
By John Ruch
© 2001
Q: Why isn’t there a reverse microwave oven to cool food quickly?
—J.D.
A: Microwave ovens heat food invisibly and quickly, without raising the air temperature in the oven. It seems like magic, so why not just reverse the spell and start flash-freezing?
The problem is that microwaves are energy in electromagnetic form. In the oven, they heat food by adding their energy to it. Cooling food requires the removal of energy, not the addition of it.
Like light and radio waves, microwaves are electromagnetic waves, but they’re of especially high frequency and wavelength. They pass easily through air and bounce harmlessly off metal and most plastics, glass and ceramics. They are extremely useful in radar and telecommunications.
They can also heat food—as long as the food contains water. (Pure oil, for example, won’t heat up in a microwave.) Within a particular frequency range, the cycling of their electromagnetic fields causes water molecules (which are electrically polarized, with a negative charge at one end and a positive charge at the other) to flip back and forth. This constant flipping makes the water molecules rub against each other very rapidly, turning the microwaves’ energy into frictional heat.
The frequency of almost all home microwave ovens is 2.45 gigahertz, which means the water molecules flip at a rate of 2.45 billion times per second. That makes for mighty fast heating. And because the microwaves penetrate all parts of the food item simultaneously, the whole thing is cooked all at once (as opposed to conventional ovens, which use hot air to cook from the outside in).
Microwave ovens are also highly energy-efficient. About 50 percent of the power required to run them goes directly into cooking, compared with only about 10 percent for conventional ovens.
Refrigeration, on the other hand, remains a difficult and relatively inefficient process. Flash-freezers are available, but they use expensive coolants and probably don’t have enough household utility to be worth it.
The problem is that energy can’t be destroyed, only moved to another place or turned into another form. It takes a lot of work to remove that energy and keep it out.
Home refrigerators and freezers work on the principle that fluids (typically Freon or a similar substance) absorb heat as they change state from liquid to gas, thus lowering the temperature of nearby objects. A gas is compressed and forced into a condenser, where it cools and liquefies, then flows into coils inside the walls of the refrigerator. Inside these coils, it vaporizes, which draws heat from the whatever’s inside the fridge. It then rises back to the compressor.
Like the conventional oven, this process ultimately is moving heat through the air. It’s hard, expensive work. Unfortunately, there is no known “cold ray” to replace it, and it’s hard to imagine how there could be one.
March 27, 2008
Lava Lamps
Stupid Question ™
Oct. 12, 2000
By John Ruch
© 2000
Q: What are the solid and the liquid inside a Lava lamp?
—Jimmy
A: Haggerty Enterprises, the US makers of the “Lava brand motion lamp,” had a simple answer: It’s a secret.
The one thing they could tell me is that the contents are non-toxic—and even that seems hard to swallow.
The Lava lamp is an upright glass cylinder containing clear fluid through which a waxy, colored substance slowly rises and falls. This “lava” rises because a light bulb in the base heats it up (via a metal coil); at the top of the lamp it cools off and sinks.
Anybody can make a cheap version of a Lava lamp—just toss some colored mineral oil into alcohol. But sophisticated chemistry is needed to produce the Lava lamp’s hypnotic, random ooze.
The folks at Haggerty have spilled more beans to other journalists, saying that the lamp contains wax and “14 secret ingredients.” They’ve also admitted that the liquid is only partly water, and that the “lava” is basically colored paraffin wax.
This jibes with the US and UK patents (the British invented Lava as the Astro Lamp), which call for “lava” to be made of mineral oil, paraffin (both liquid and solid), a dye and carbon tetrachloride (a dry-cleaning solvent that probably makes the stuff a little more dense than water).
The US patent calls for the liquid to be about 70 percent water, and about 30 percent some other liquid that apparently increases the viscosity and the rate of heat transfer. The patent suggests propylene glycol, glycerol, ethylene glycol or polyethylene glycol. In layman’s terms, that’s solvent, laxative or antifreeze.
We know which one Haggerty uses, thanks to one of those bold souls without whom we never would’ve made it out of the caves: a 65-year-old Chicago man who, according to the June 1996 “Annals of Emergency Medicine,” drank the liquid in a Lava lamp. He suffered kidney failure.
Hospital analysis revealed the lamp contained polyethylene glycol, as well as chlorinated paraffin, “microcrystalline wax” and, surprisingly, kerosene (possibly used to thin the paraffin, and responsible for the fuel-like smell given off by broken lamps). So much for “non-toxic.” (Clearly, Haggerty is assuming you won’t chug an entire lamp.)
Of course, this doesn’t account for all 14 “secret ingredients.”
However, common problems with Lava lamps are fertile grounds for guesses. For example, all lamps eventually wear out, at which time the “lava” separates into two masses. One floats, and one sinks. This has led hobbyists to speculate that it contains some sort of powder in solutions, such as talc or silica, which eventually precipitates down into the bottom of the “lava” ball.
Oct. 12, 2000
By John Ruch
© 2000
Q: What are the solid and the liquid inside a Lava lamp?
—Jimmy
A: Haggerty Enterprises, the US makers of the “Lava brand motion lamp,” had a simple answer: It’s a secret.
The one thing they could tell me is that the contents are non-toxic—and even that seems hard to swallow.
The Lava lamp is an upright glass cylinder containing clear fluid through which a waxy, colored substance slowly rises and falls. This “lava” rises because a light bulb in the base heats it up (via a metal coil); at the top of the lamp it cools off and sinks.
Anybody can make a cheap version of a Lava lamp—just toss some colored mineral oil into alcohol. But sophisticated chemistry is needed to produce the Lava lamp’s hypnotic, random ooze.
The folks at Haggerty have spilled more beans to other journalists, saying that the lamp contains wax and “14 secret ingredients.” They’ve also admitted that the liquid is only partly water, and that the “lava” is basically colored paraffin wax.
This jibes with the US and UK patents (the British invented Lava as the Astro Lamp), which call for “lava” to be made of mineral oil, paraffin (both liquid and solid), a dye and carbon tetrachloride (a dry-cleaning solvent that probably makes the stuff a little more dense than water).
The US patent calls for the liquid to be about 70 percent water, and about 30 percent some other liquid that apparently increases the viscosity and the rate of heat transfer. The patent suggests propylene glycol, glycerol, ethylene glycol or polyethylene glycol. In layman’s terms, that’s solvent, laxative or antifreeze.
We know which one Haggerty uses, thanks to one of those bold souls without whom we never would’ve made it out of the caves: a 65-year-old Chicago man who, according to the June 1996 “Annals of Emergency Medicine,” drank the liquid in a Lava lamp. He suffered kidney failure.
Hospital analysis revealed the lamp contained polyethylene glycol, as well as chlorinated paraffin, “microcrystalline wax” and, surprisingly, kerosene (possibly used to thin the paraffin, and responsible for the fuel-like smell given off by broken lamps). So much for “non-toxic.” (Clearly, Haggerty is assuming you won’t chug an entire lamp.)
Of course, this doesn’t account for all 14 “secret ingredients.”
However, common problems with Lava lamps are fertile grounds for guesses. For example, all lamps eventually wear out, at which time the “lava” separates into two masses. One floats, and one sinks. This has led hobbyists to speculate that it contains some sort of powder in solutions, such as talc or silica, which eventually precipitates down into the bottom of the “lava” ball.
Fans Heating Up Air
Stupid Question ™
March 9, 2000
By John Ruch
© 2000
Q: If heat is just molecular movement and fans stir up air molecules, why doesn’t a fan make you hotter?
—Sarah Pessin
A: It’s sort of like trying to knock over a wall with your pinkie—the energy’s there, but other forces are so strong it doesn’t matter.
As long as air is relatively cool and dry, the overheated human body can dump excess heat into it by convection and evaporation.
Convection is the way heat moves through a fluid. Heated areas become less dense due to increased molecular motion and rise; cool areas become denser due to decreased molecular motion and sink. As long as there’s a constant heat source, convection will continue in this rise-and-sink cycle.
Thus, cooler air near the human body will heat up and rise away, removing some heat. Cool air will sink to replace it, and the cycle continues until the body cools or the air gets too hot.
Sweating works even better because the evaporation of water into dry air removes a lot of heat.
A fan makes both these slow processes faster and more effective by moving air around. Circulating air around the body forces convection to take place and moves drier air to the body so evaporation can continue. (If the air isn’t cooler or drier that the body, the fan does nothing to make you more comfortable.)
It is true that a fan will increase the average temperature of a closed room by speeding up air molecules, by causing friction between the air and solid surfaces, and by giving off the heat generated by the motor.
However, this heating is insignificant compared to the large personal cooling effects.
Heating by moving molecules is especially weak because the fan moves air on a macroscopic level. While the fan does cause some individual air molecules to speed up, it mostly just moves a big chunk of air within which most molecules continue to bounce around at their usual average speed. Therefore, the heating effect is minimal.
The radiant heat from the fan’s motor is much stronger, and even it doesn’t matter compared to the large cooling effects. (In fact, there are electricity-free fans that run on an open alcohol or kerosene flame.) Even the heat gain caused by waving a handheld fan is somewhat less than the cooling effect.
On top of it all, the heating effects virtually disappear in a room with an open door or window, and thus a constant supply of fresh air.
To keep my physicist friends happy, I must also point out that technically, heat isn’t just molecular motion. It’s the internal energy of a substance.
It’s not identical with temperature, which is a measure of average kinetic energy (motion) of molecules. For example, a 2-pound stone and a 1-pound stone can be at the same temperature (average kinetic energy), but the bigger stone will take longer to cool down because it has more heat energy.
March 9, 2000
By John Ruch
© 2000
Q: If heat is just molecular movement and fans stir up air molecules, why doesn’t a fan make you hotter?
—Sarah Pessin
A: It’s sort of like trying to knock over a wall with your pinkie—the energy’s there, but other forces are so strong it doesn’t matter.
As long as air is relatively cool and dry, the overheated human body can dump excess heat into it by convection and evaporation.
Convection is the way heat moves through a fluid. Heated areas become less dense due to increased molecular motion and rise; cool areas become denser due to decreased molecular motion and sink. As long as there’s a constant heat source, convection will continue in this rise-and-sink cycle.
Thus, cooler air near the human body will heat up and rise away, removing some heat. Cool air will sink to replace it, and the cycle continues until the body cools or the air gets too hot.
Sweating works even better because the evaporation of water into dry air removes a lot of heat.
A fan makes both these slow processes faster and more effective by moving air around. Circulating air around the body forces convection to take place and moves drier air to the body so evaporation can continue. (If the air isn’t cooler or drier that the body, the fan does nothing to make you more comfortable.)
It is true that a fan will increase the average temperature of a closed room by speeding up air molecules, by causing friction between the air and solid surfaces, and by giving off the heat generated by the motor.
However, this heating is insignificant compared to the large personal cooling effects.
Heating by moving molecules is especially weak because the fan moves air on a macroscopic level. While the fan does cause some individual air molecules to speed up, it mostly just moves a big chunk of air within which most molecules continue to bounce around at their usual average speed. Therefore, the heating effect is minimal.
The radiant heat from the fan’s motor is much stronger, and even it doesn’t matter compared to the large cooling effects. (In fact, there are electricity-free fans that run on an open alcohol or kerosene flame.) Even the heat gain caused by waving a handheld fan is somewhat less than the cooling effect.
On top of it all, the heating effects virtually disappear in a room with an open door or window, and thus a constant supply of fresh air.
To keep my physicist friends happy, I must also point out that technically, heat isn’t just molecular motion. It’s the internal energy of a substance.
It’s not identical with temperature, which is a measure of average kinetic energy (motion) of molecules. For example, a 2-pound stone and a 1-pound stone can be at the same temperature (average kinetic energy), but the bigger stone will take longer to cool down because it has more heat energy.