Category Archives: General Science

Lithium

A couple of decades ago and without having taken at least a high school chemistry course most would not have heard of Lithium, nor use it in their daily lives. Now however it dominates the battery world. Disposable Lithium metal batteries power all sorts of devices which require the packing a lot of power in a small space . In addition to AA and AAA batteries, Lithium metal batteries power virtually all the “coin” batteries in small devices such as hearing aids and watches. Lithium metal batteries also have an illicit use as a reagent in the synthesis of methamphetamine but that is another story.

Lithium metal batteries pack about twice the punch as Lithium ion batteries for a given size. More important for many applications is the fact that Lithium ion batteries are rechargeable, greatly increasing their utility. Everything from cell phones to plug-in hybrids (electric cars which can be charged at home or work) utilize the rechargeable aspect of lithium ion batteries.

Lithium is a metal but the periodic chart is populated by scores of metals, in fact the majority of elements in the universe are metals. What makes Lithium unique is it’s charge to weight (and volume) ratio. Lithium metal is the lightest metal and can exist as a stable ion. This means it is capable of giving up or accepting an electron, a necessary function of a battery. Think of a charged battery as reservoir of electrons. When a battery powered device is turned on a circuit is completed which allows the electrons to flow. This is the electric current which does what ever work of a device was built for, be it lighting a light bulb or powering an electric automobile.

As the reservoir of electrons is depleted the battery loses power. Rechargeable batteries are capable of reversing the loss of electrons by pushing electrons back into the battery.

Rechargeable batteries are at the heart of numerous university, government, and private research facilities for two obvious reasons. First, electric powered transportation is the future but contemporary batteries have a limited range. Equally limiting is the long recharge times required. To replace internal combustion engine powered cars, battery powered electric cars and going to have to have a several hundred mile range and a few minutes recharge time. That is a tall order.

So is there enough Lithium out there to meet the increasing demand? Do we have supplies here in the US or do we have to buy it from other countries? Can we afford it? All valid questions. Lithium is present in the earth’s crust at about 20 parts per million (PPM.) This doesn’t sound like much but it more than more commonly known metals such as Lead and Mercury.

Currently we import about 80% of our Lithium needs, but recent prospecting has turned up brine deposits in Wyoming which may provide for our need for sometime into the future. Ultimately the world’s richest deposits of economically recoverable Lithium are in the Atacama desert on the Pacific coast of Chile. Unrelated factoid – the Atacama is the driest place on earth.

Seawater to Fuel?

The United States Navy recently announced that they had invented a process to turn sea water into fuel. It’s not exactly the water, but rather the water and Carbon Dioxide dissolved in the water which is turned into fuel.

Is this a game changer? Is it time to quit drilling for oil or digging for coal? No more nuclear reactors and the dangerous wastes, or even wind turbines, which kill so many birds and bats? No more deserts covered with solar panels? Hallelujah.

synthfuel

synthfuel

Scientists at the Naval Research Laboratory have found a way to extract Carbon Dioxide from the seawater, at the same time generating Hydrogen. These gases are then combined in the presence of a catalyst to become the equivalent of jet fuel.

Logistically this could be big for the Navy. Fuel could be produced while at sea lessening the risks of refueling in hostile waters. Remember the USS Cole? It was a guided missile destroyer that docked in Aden, Yemen for refueling. While there she was attacked by al-Qaeda resulting in the death of 17 sailors.

USS Cole

USS Cole

In addition to the production of jet fuel, with only slight modification of the process and or the catalyst, fuel for everything from cars to power plants to home heating oil can easily be produced. Seaside plants could churn out all the fuel the world needs right? Not exactly.

What has been neglected or at least not emphasized is the fact that the current process takes twice the electrical energy to produce the fuel as you get back when the fuel is burned. Bummer. It has been suggested that the process can be made more efficient. But there are absolute limits.

The first law of thermodynamics says, and I’m paraphrasing here – there is no such thing as a free lunch – when it comes to energy. The energy content of fossil fuels derive their energy from the sun. To make the fuel from sea water takes energy. But it gets worse, the second law of thermodynamics says you can’t even break even. There is no such thing as a 100 per cent efficient energy conversion process. There are always losses. Because of these simple laws, laws which can’t be broken, it will always take more energy than you get out in any energy conversion process.

Back to the navy. The process as noted may have logistical advantages, but it is no magic bullet for energy production. A ship at sea would have to supply energy, more than you get out, to produce the fuel. For fossil fuel powered ships this is a non-starter. Nuclear powered ships could use some of the nuclear power to generate electricity for the fuel production, but it would mean shorter durations between nuclear refueling.

Remember, there is no such thing as a free lunch, and you can’t even break even. Unlike Jaywalking or bank robbery, these laws can’t be broken.

Phantom Loads

A while back a congressman at a town hall meeting suggested that federal research dollars were being wasted and gave as an example a study examining how much energy is used when a consumer electronic device was turned off. Everybody knows that electronic devices don’t use power when turned off, right?

I am sure the line drew a laugh and the was object of derision of the crowd, but the irony is that the questioned study aimed at reducing waste and therefore saving, not wasting dollars. Real money is wasted on a daily basis due to phantom loads.

image credit: www.nativeenergy.com

image credit: www.nativeenergy.com

Many consumer devices such as televisions, computer printers, video gaming devices, and others are actually in standby, not off when switched off. These phantom loads or sometimes called vampire loads use significant amounts of energy.

There are two basic reasons for the phantom energy use. One is for convenience. Televisions, DVRs and such, are left in stand by mode so that they will come on more quickly. These are so called instant on devices. My LCD television has a little red light which glows when the television is “off” meaning of course that it is still on even though it is turned off. It may be off for 20 hours a day, but is still using power so that it will come on six seconds faster that if it had been unplugged. I use a couple of bucks a year for that six seconds. A couple of bucks a year for just one device is no big deal, but most homes have several instant on devices.

image credit: www.nativeenergy.com

image credit: www.nativeenergy.com

image credit: www.nativeenergy.com

image credit: www.nativeenergy.com

The other type of phantom load comes from the need to transform alternating current (AC) to direct current (DC). AC is the type of electricity that comes out of the wall. It is what the power company delivers and sells to you. Direct current on the other hand is what is used to power some devices and especially to charge anything with a battery. Collectively these are the devices with “the brick”, a transformer. You plug the brick into the wall and then it gets plugged into a device, say a cell phone. Even without the cell phone plugged in (or the computer printer or the computer speakers, or the wireless telephone, et. al.) they are still using power.

The instant on devices use only a fraction of the power when in stand by mode, but the fact that there are numerous devices in a home and they are in this mode most of the time means it can add up. The power bricks are especially inefficient, wasting anywhere from twenty to a whopping eighty percent of the energy consumed. This wasted energy is ultimately lost in the form of heat, adding to air conditioning loads in season. For the average household six to ten percent or more of total power to consumer electronic devices is attributed to phantom loads.

image credit: www.nativeenergy.com

image credit: www.nativeenergy.com


The only answer to reducing these phantom loads is to unplug or “unpower” the device when not in use. A few power strips at strategic locations around the house can save energy. And every bit of energy not used is beneficial to the environment and your pocketbook.

rosebush

You’re Dead – Now What?

The oldest known burial remains in North America were found in Montana. A two year old child was interred with numerous valuable artifacts, almost 13,000 years ago. The artifacts, stone tools for example, indicated the child was of the Clovis culture, so named for a distinct style of arrow heads first found in Clovis, New Mexico.

burial site of Clovis Child

burial site of Clovis Child

Interestingly Clovis Culture artifacts are widespread across North America but this is the first skeletal remains found and examined by DNA analysis. DNA confirmed the Siberian ancestral origin of native Americans.

Burial, with or without embalming, has been and to this day remains to be the most common method of disposal of human remains in the United States, but this appears to be changing. About two thirds of us are buried, the remainder cremated. Cremation rates vary considerably by state. In Mississippi only one in ten are cremated whereas seven in ten are cremated in Nevada. Here in Arkansas about 20 per cent are cremated. In some parts of Europe cremation rates are over 90 per cent.

crematory

crematory


Cremation began in the United States late in the nineteenth century, and the number cremated has slowly increased. It was initially promoted as a healthy alternative as it had been thought that bodies moldering in the ground gave of toxic airs known as miasma. Today modern crematoria such as that proposed here in the River Valley are fired with natural gas and fitted with exhaust scrubbers to recover much of the Mercury emissions coming from dental amalgams.

Cremation costs have risen with the cost of energy and also the cost for the advanced scrubbers for Mercury removal. This has driven the search for other alternatives. The most developed alternative technology to date involves what is called alkaline hydrolysis. A body is put in a chamber with water and lye which then is heated and pressurized to digest the body. Other than the large bones the only thing remaining is a sterile solution which literally goes down the drain. Alternatively the solution can be neutralized and used as a nutrient rich solution for watering plants.

A possibly more respectful and less wasteful disposal of humans could involve some sort of recycling. A process for composting human remains is being examined by a Swedish Company – Promessa. Rather than a human body being combined with vegetable peels in a compost pile, this company uses freeze drying. Completely dehydrated remains are pulverized, placed in biodegradable boxes and then buried in shallow graves. The nutrients from the body provide excellent fertilizer for subsequent plantings.

In Arkansas human remains can be buried without embalming and in rural areas a family cemetery could be the final resting place. So you’re last decision could be whether to fertilize, and hence become one with, a bed of roses or maybe a fruit tree or for longevity even an oak tree.

waterfall

What Price Clean Water?

The Cuyahoga River last caught on fire in 1969, but had burned uncontrolled on numerous occasions dating back to the latter half of the the nineteenth century. The river flows north through northern Ohio and Cleveland into Lake Erie. Numerous industries discharged wastes into the river to the extent that at times the river was coated with several inches of highly flammable sludge.

Cuyahoga on Fire

Cuyahoga on Fire

The 1969 fire along with a growing environmental movement resulted in the passage of the Clean Water Act in 1972. The waters of the nation have benefited from the laws, but problems still exist, especially when it comes to our demand for cheap energy in the form of fossil fuels and even cheaper food.

In one of the ironies of our time, a chemical used to clean coal means that the drinking water of Charleston, West Virginia is not so clean. In January 2014 several thousand gallons of an industrial chemical leaked from a Freedom Industries storage tank on the banks of the Elk river, just upstream of the drinking water intake for several hundred thousand people. To this day, some residents of the area refuse to drink the water as it still smells faintly of licorice.

In North Carolina, the Dan River has recently been contaminated by a pipe failure from a coal ash containment pond owned by Duke Energy. The river and even groundwater are now polluted with sludge that is highly contaminated with Arsenic, a heavy metal that is both toxic and carcinogenic. There are fears that the massive 40,000 ton spill is not over as another pipe may be leaking.

What these Clean Water Act violations have in common is that both were easily preventable. Had the responsible corporations taken care of business, the spills would never have happened. And had the responsible regulatory agencies done their job the problems that caused these spills would have been prevented. But no, businesses don’t want to spend extra money and taxpayers don’t want to properly fund the agencies that provide oversight.

A similar disaster is brewing in Arkansas. In our case it is not the result of industrial use of fossil fuels but the industrial wastes from a confined animal feeding operation (CAFO.) The hog farm, the first of its type in the watershed of the crown jewel of Arkansas, the Buffalo National River, was permitted by a deeply flawed process. The Arkansas Department of Environmental Quality granted a general permit for the operation. It did not consider the sensitive location in the Buffalo watershed, nor consider the uniquely porous limestone geology of the Ozarks.

CAFO

CAFO

Thousands upon thousands of gallons of liquid wastes, urine and feces, are contained in two ponds. The permitted design required only enough free board to contain a 25 year rain event. When the dirt bank ponds are breached, they will likely fail catastrophically, releasing the wastes into Big Creek and a few miles downstream, the Buffalo River National Park. Even during times when the banks hold, the clay lined ponds are allowed to leak wastes through the soil. Because of the Karst topography, the wastes can make their way rapidly to pollute the nation’s fist national river. Its not a matter of if but when.

Why do we continue to set ourselves up for these kinds of disasters? Because of short sightedness. Because we just can’t seem to learn that proper regulation of industry takes careful oversight, and the funding to provide for it.

fishy

Solunar Tables – a Fish Tale

Every morning, Television weather forecasters advise their viewers as to when is the best time to catch a fish. They have oh-so-scientific-looking graphs that tell you that you should go out between 12:52 and 1:47 AM or at 3:30 PM or other such specific times on given days.

Did you ever wonder where this came from? The best times to fish or to for that matter to hunt are calculated from Solunar tables – obviously catfish bite at the same time of day that deer make themselves available for shooting. Sure, lots of fish and game seem to be more active during the twilight hours around dawn and dusk, but that’s not what the solunar tables are all about. They are constructed from astrophysical relationships of the sun, the earth and the moon.

solunar table for fishing

solunar table for fishing

The idea behind this is that humans have been hunting and fishing for hundreds of thousands of years, so surely that wisdom can be subsumed by a scientific approach. In 1926 a fellow by the name of John Alden Knight looked at what he thought were 33 factors which influence the behavior of both fresh and saltwater fish. His studies revealed, he claimed, that only three recurrent factors mattered. They are The positions of the sun and the moon, and the tides. Obviously tides aren’t an issue here in Arkansas, so we are left with the solunar (sol for sun and lunar for moon) effect.

When the original research was done only the approximate time of moon rise and set were used. This was later refined to include intermediate periods of activity that occurred midway between the two major periods. Thus the more evident periods were called major periods and the two intermediate periods, shorter in length, were called minor periods.

That’s it. Fisherman’s tales not withstanding, I find no credible reports with properly controlled studies which support this hypothesis. So why do the use of solunar tables persist? My guess is the old expression “even a blind squirrel finds an acorn once in a while.” Combine dumb luck with the propensity to remember positive results and forget (or reject) negative results and you have the immutable solunar theory of hunting and fishing.

So what’s the harm? It’s the fact that a weatherperson on a local television station, if trained in meteorology, is about as close to a real scientist as a lot of folks get. I would hope that a scientifically trained person would do a better job of distinguishing between what is real and what is not. As a scientist I try my best to be guided by a definition of science from one of the great minds of the twentieth century, Nobel Prize winning theoretical physicist Richard Feynman. “Science is what we do to keep from fooling ourselves.”

If you want go fishing, go when the weather is nice, take a beverage of choice, and don’t expect to catch a fish. You will not be disappointed. If you do catch a fish, well that is even better.

halite

Salt of the Earth

The history of civilization is closely connected to salt. Up until about 100 years ago salt, Sodium Chloride, was one of the most sought after commodities known. The word salary derives from Latin salairum or salt money. Roman soldiers were paid in salt.

The importance of salt pervades our language with numerous expressions: not worth his salt, salt of the earth, back to the salt mine,

salt mine diorama

salt mine diorama

rub salt in the wound, and others.

The Catholic church dispenses not only holy water but also holy salt, Sal Sapientia, the salt of wisdom. In the Torah, the book of Numbers, is written: “ It is a covenant of salt forever before the Lord…” A custom in medieval Europe was to put salt in the mouth of a newborn, as evil spirits apparently feared salt. Protection against the bad luck of spilling salt was to throw salt over ones shoulder to “cover your back” from evil spirits.

So why the importance of salt? First and foremost it is essential to life as indicated by the fact that we have a taste bud dedicated just to salt. Salt, more specifically the Sodium ion, is used to control nervous transmission in all forms of life. Substances which interfere with Sodium binding at specific surfaces within cells, called Sodium channels, are powerful poisons.

Too much of good thing however is a problem and the human population has a problem with salt. Because salt readily dissolves in water it can’t be stored in the body for future use but must be replaced daily. The world health organization (WHO) set an upper level of salt consumption at five grams – a scant teaspoon- per person per day. WHO surveys show that global salt consumption per capita nearly twice the recommended amount.

“Nearly all populations across the world are consuming far more sodium than is healthy,” said Dr Dariush Mozaffarian, from the Harvard School of Public Health. “Clearly, strong government policies are needed, together with industry cooperation and collaboration, to substantially reduce sodium.”
Heart disease is the leading cause of death worldwide and is impacted by high blood pressure which correlates with high salt consumption. Also stroke, kidney failure, and blindness are all indicated in hypertension (high blood pressure).
An additional use of salt which becomes a health issue is its use as a food preservative. Fishermen from Scandinavia were able to market Cod across Europe and beyond via salting as a preservative. Salt dehydrates tissues which makes them more stable to bacterial spoilage. Salt cured ham, corned beef, pickles, and Kimchi are just a few of salt preserved foodstuffs.
The historical importance of salt cannot be over emphasized. The Doges of Venice and Genoa acquired wealth and power from the sale of salt collected from solar evaporation ponds on the Mediterranean and Adriatic sides of Italy.

Landscape with Mill near the Salt Ponds

Landscape with Mill near the Salt Ponds

One of the reasons Jefferson sent Lewis and Clark west was the rumor of a salt mountain near the Missouri River. The collapse of British rule in India began when Mohandas Gandhi lead a protest against a salt tax.
Sequoyah

Sequoyah


A local connection with salt is the big black cauldron in the center of Dover, AR. Sequoyah, creator of the Cherokee syllabary, lived north of Dover on the Illinois Bayou in the 1820s. He used the pot to boil down brine from a saline seep to make salt.

nose

How Do You Smell

Last week a chemical spill polluted the drinking water of Charleston West Virginia. Over 7,000 gallons of a chemical used to process coal were dumped into the Elk river just upstream of the city’s water supply intake pipe. The leak was detected because the water took on the smell of licorice.

Among the traditional five senses; sight, hearing, touch, taste and smell, smell is unique. As it is an eminently chemical sense.

When you see a bowl of onion soup or for that matter a rotting possum by the side of the road, your perception is due to light reflected off the surface of these objects. Smelling either of these is chemical as it requires the movement of molecules from the object through the air and up into your nostrils. The molecules bind at specific sites, called receptors, which then causes the sending of signals through nerves to a specific area of the brain.

Different things smell differently because the molecules given off have different shapes and so bind at different receptors. Humans are though to have about 5 or 6 million receptors compared with rabbits, about 100 million, or dogs with over 200 million.

nasopharynx

nasopharynx

Smell is also unique in that it is difficult to quantify. How bright a light is can easily be measured in units of lumens and how loud a noise is in decibels. No such quantifiable scale exists for smells. We can talk about something smelling strongly or not but that is about all. And when it comes to qualitative measures it is difficult to get two people even to agree if something is an agreeable or a disagreeable odor.

Strangely the qualitative descriptor for a particular substance can depend on the concentration, that is, how many receptors bind with a substance. An extreme example is a molecule called skatole, which comes from feces, especially that of carnivores. Humans are very sensitive to this odor, probably because evolutionarily those individuals insensitive to the smell of the excrement of a saber-tooth tiger didn’t survive to produce offspring. Those sensitive individuals knew to clear out, and were more successful at producing progeny.

Here’s the crazy part. This same molecule known as skatole which is the essence of smelly animal poop, is used in perfumery! In very low concentrations it is perceived as an agreeable odor. Weird huh?

Smell is all about communication, from the simplest single celled organisms up to and through the plant and animal kingdoms. Sexual activity among animals is frequently modulated by chemical signals, called pheromones, from females to males.

The same is true in the arthropod world. Molecular trickery even exits. There are spiders which have evolved to produce the same pheromone as a prey moth. The spider sits in its web, emits the moth pheromone and then waits for the unsuspecting males moths looking for a good time.

Humans are no exception, but communication is on an unconscious level. Brain scans show that men and women react differently when exposed to the odor of certain hormones, even though they are not consciously aware. It’s been suggested that the use of perfume or cologne is not so much to smell nice as it is to disguise our true smells.

An odd feature of unconscious odor communication is the fact that women living in close physical proximity synchronize there menstrual cycles. There must be an evolutionary advantage but it is hard to imagine what that would be. One possibility considering that humans lived in small hunter-gathering societies 10 or 15 thousand years ago: Could it be that once a month all the men said -whoa boys, it’s that time of the month, maybe we should go off hunting for a few days.

tablet

Worried Sick- the Nocebo Effect

A synthetic form of thyroxine called Eltroxin, chemically and biologically identical to natural thyroxine, has been in use for over forty years. It is used effectively to treat hypothyroidism which if left untreated can result in a range of symptoms up to and including heart disease. In 2007 GlaxoSmithKline moved its manufacture from Canada to Germany. At the same time they updated the actual tablet, changing its physical form but leaving the active ingredient the same.

Shortly thereafter in New Zealand a trickle of reports of adverse side effects not seen before were received by a health monitoring organization. After the new side effects began to show up in the press, reports of the new symptoms skyrocketed over a thousand fold even though the only difference was the appearance of the pills, not the chemistry.

A study by a team of Italian gastroenterologists involved patients who were lactose intolerant and a control group who weren’t. The subjects were told that the study involved examining the effects of lactose on the gut. Even though the subjects were given only a glucose tablet which can not cause symptoms, forty four percent of those intolerant and and 26 percent of those tolerant, reported gastrointestinal problems.

Many here in the US and overseas suffer from a so called WiFi syndrome. A range of symptoms including nausea, head aches, joint pain etc. occur when they know they are exposed to electromagnetic fields, but only if they know they are exposed. There is absolutely no evidence that the EMF can cause these symptoms.

These examples are only three of hundreds of examples of what is know as the nocebo effect, from latin for “I shall harm”. In years past this may have been referred to as a form of mass hysteria, now more benignly called a psychogenic illness. In some cases it has been shown that the mere suggestion of a possible symptom or side effect can cause a biochemical change in the body which results in the symptom, but only from the suggestion.

This was shown elegantly in an animal model using rats. They were trained by classical Pavlovian training to become asthmatic. First the experimenters gave the rats a natural substance, histamine, which causes an asthma reaction and paired that with the ringing of a bell. In subsequent trials just the bell ringing would cause the rats to release excess histamine into their blood, thus triggering an asthma attack. If rats can be trained to become asthmatic, shouldn’t it be true that people who have asthma reactions could be trained to not react?

The nocebo effect is the evil twin of the better known placebo effect, latin for “I shall please”.

nocebo and placebo

nocebo and placebo

Any benefits of homeopathic medicine, and much folk medicine are a result of the placebo effect, including modern day agents associated with Traditional Chinese Medicine, acupuncture, much of chiropractic, and over the counter medications called nutritional supplements.

The question as to whether society should allow profit from the sale of placebos is a moral one. Should some one make money by suggesting that a nostrum will do something, even if it only works for believers? It sure works for Madison Avenue. Ca-ching.

Lighting Technology

The phrase “She would rather light a candle than curse the darkness” came from a Eulogy given by Adlai Stevenson for Elanor Roosevelt. This is of course a metaphor, as the bringing of light refers to bringing knowledge to an unknowing hence dark world. Aphorisms aside, let’s be literal. Let’s talk about lighting technology.

There is good evidence that one of our ancestors, Homo erectus learned to control fire close to a half a million years ago. Fire provided heat, protection from predators, and light to extend the day into night. The campfire of Homo erectus was wood and provided much more light than heat. Light was a byproduct.

Technology expanded light production with the creation of oil lamps about six thousand years ago. Made from clay, lamps were found at numerous sites, and depending on location these were fueled by animal fat, vegetable oil or even petroleum oil from natural seeps. The related technology of candles came later, possibly originating in China about three thousand years ago. The Chinese candles were made of whale fat. Other materials for candles include tallow, beeswax, and contemporaneously paraffin, a solid petroleum derivative.

Kerosene lanterns, still in use in much of the world were common by the nineteenth century. Gas lamps, using gas as opposed to liquid developed about the same time and were popular as stationery light sources, e.g, street lamps.

All these light sources share one property – combustion. Burning something, combustion, is an exothermic process. Burning gives off heat, and if you give off enough heat you get (visible) light. Thomas Edison recognized that if you get something hot enough, whether burning or not, you get light.

Incandescent 16 Lumens per watt

Incandescent 16 Lumens per watt

His invention, the incandescent light bulb (ILB) employing electricity, revolutionized lighting and has illuminated the modern world since the start of the twentieth century.

The new revolution in lighting technology is the production of light sources much more efficient than incandescent bulbs. ILBs work by the heat, then light produced by resistance to the flow of electricity through the Tungsten filament. But it is an astoundingly inefficient process when illumination is the objective. Only about five percent of the energy consumed by an ILB produces light, the remainder is given off in the form of heat.

Luminous efficacy is measured by the product of the amount of light measured in lumens, divided by the energy to power it measured in watts. The luminous efficacy of an ILB is sixteen lumens per watt.
ILBs are cheap to produce but waste energy. More efficient are compact fluorescent bulbs (CFB).

a 100 watt equivalent clf uses about 28 watts

a 100 watt equivalent clf uses about 28 watts

These have a luminous efficacies of about fifty to sixty. They are therefore cheaper to operate but have a few drawbacks; they take time to reach full illumination especially at low temperatures, they aren’t dimmable, and they contain small amounts of Mercury which complicates disposal.

The most promising entry to inexpensive lighting are Light Emitting Diode light sources. They are everywhere already in electronic technology in the form of various indicator lights. These LEDs have now been ganged in groups to produce illumination with efficiencies of over one hundred.

100 watt equivalent LED uses less than 22 watt

100 watt equivalent LED uses less than 22 watt

LEDs don’t suffer from the deficiencies of other bulbs; they are very efficient, “instant on”, dimmable, cool to the touch, non toxic, and will become even more efficient as they are developed. The future for LED lighting is bright indeed.