Aristotle (350 B.C.) disagreed with Democritus's model of the atom in Aristotle was a Greek philosopher. Many of his ideas were more thought based than scientifcially based. For this reason, Aristotle strongly disagreed with Democritus. He felt that there was no smallest part of matter and that different substances were made of earth, fire, air, and water. Aristotle did not have an atomic model due to the fact that he thought atoms did not exist.
Democritus was the first scientist to create a model of the atom. He was the first one to discover that all matter is made up of invisible particles called atoms. He created the name "atom" from the Greek word "atomos", which means uncuttable. He also discovered that atoms are solid, insdestructable, and unique. HIs model was just a round solid ball. Democritus didn't know about a nucleus or electrons, all he knew was that everything is made of atoms.
Lavoisier was a French nobleman that founded several elements and put the first table of elements together. He used Aristotle's ideas of fire, earth, air, and water to create experiments invesigating combustion and oxidation. By using previous knowledge of atomic bonding, he discovered important elements like oxygen, hydrogen, and sulfur. He discovered that water was made of oxygen and hydrogen, and air included nitrogen. Lavoisier also created the first chemistry textbooks and tables.
Dalton's atomic theory
John Dalton (1766-1844)
John Dalton developed an atomic theory in the 1800s. He did experiments, worked out some atomic weights and invented symbols for atoms and molecules. His most important conclusions are summarised below:
All matter is made of atoms
Atoms cannot be broken down into anything simpler
All the atoms of a particular element are identical to each other and different from the atoms of other elements
Atoms are rearranged in a chemical reaction
Compounds are formed when two or more different kinds of atoms join together
Dalton's theory was developed and changed as new evidence was discovered.
JJ Thomson's discovery of the electron
JJ Thompson discovered the electron in 1897. This showed that the atom contained smaller pieces, whereas Dalton had thought that atoms could not be broken down into anything simpler.
Rutherford's nuclear atom
In 1911 Ernest Rutherford used experimental evidence to show that an atom must contain a central nucleus. This was further evidence that an atom contained smaller pieces.
Bohr's electron orbits
Niels Bohr further developed Rutherford's nuclear atom model. He used experimental evidence to support the idea that electrons occupy particular orbits or shells around the nucleus of an atom.
The development of the theory of atomic structure is an example of:
How a theory may change as new evidence is found
How a scientific explanation is provisional but may become more convincing when predictions based on it are confirmed later on.
Marie and Pierre Curie were a European couple that contributed to atomic chemistry by exploring the mysteries of radioactivity. After radiation was discovered by Henri Baquerel, Marie decided to look further into this discovery. Through this she and her husband discovered the elements radium and polonium and won the Nobel Peace Prize for their works in radioactivity. Her discovery later added to the atomic model.
Chlorine was discovered in 1774 by the chemist Karl Scheele . One of the first known uses of chlorine for disinfection was not until 1850, when Snow used it to attempt to disinfect London’s water supply during that now-famous cholera epidemic. It was not until the early 1900’s, however, that chlorine was widely used as a disinfectant . Chlorine revolutionized water purification, reduced the incidence of waterborne diseases across the western world, and “chlorination and/or filtration of drinking water has been hailed as the major public health achievement of the 20th century” . Chlorine remains the most widely used chemical for water disinfection in the United States . However, close to 1 billion people in the world still lack access to safe drinking water, and new questions about health effects from chlorine by-products formed during disinfection have led to questions about the advisability of using chlorine to provide safe water for this population. This page summarizes information about the production, and health effects, of disinfection by-products (DBPs).
These guidelines must be evaluated in context of the WHO Guidelines which state: "Infectious diseases caused by pathogenic bacteria, viruses, protozoa, and helminths are the most common and widespread health risk associated with drinking-water" (Chapter 7, Microbiological Aspects; Section 7.1, pg 118). Additionally, a previous version of these guidelines states: "Where local circumstances require that a choice must be made between meeting either microbiological guidelines or guidelines for disinfectants or disinfectant by-products, the microbiological quality must always take precedence, and where necessary, a chemical guideline value can be adopted corresponding to a higher level of risk. Efficient disinfection must never be compromised" (Chemical Aspects; Section 3.6.4, pg 49/65).
In disinfection, gaseous chlorine (Cl2) or liquid sodium hypochlorite (bleach, NaOCl) is added to, and reacts with, water to form hypochlorous acid. In the presence of bromine, hypobromous acid is also formed. Both chlorine and bromine are in the “halogen” group of elements, and have similar chemical characteristics. Hypochlorous and hypobromous acid form strong oxidizing agents in water and react with a wide variety of compounds, which is why they are such effective disinfectants.
In 1974, Rook discovered that hypochlorous acid and hypobromous acid also react with naturally occurring organic matter to create many water disinfection by-products, including the four primary trihalomethanes:
Chloroform – CHCl3
Bromodichloromethane (BDCM) – CHCl2Br
Dibromochloromethane (DBCM) – CHClBr2
Bromoform – CHBr3
At the center of each of the four trihalomethanes is a carbon atom, and it is surrounded by and bound to four atoms: one hydrogen and three halogens. These four compounds are collectively termed trihalomethanes and are abbreviated as either THM or TTHM (for total trihalomethanes).
Rook’s discovery of THMs in drinking water led to research on other chemicals formed when chlorine is added to water, and to the health effects of these chemicals. Richardson identified greater than 600 water disinfection by-products in chlorinated tap water, including haloacetic acids (HAAs). THMs, and to a lesser extent HAAs, are currently used as indicator chemicals for all potentially harmful compounds formed by the addition of chlorine to water. In many countries the levels of THMs and HAAs in chlorinated water supplies are regulated based on this assumption.
Humans are exposed to DBPs through drinking-water and oral, dermal, and inhalational contact with chlorinated water 6. In populations who take hot showers or baths, inhalation and dermal absorption in the shower accounts for more exposure to THMs than drinking water .
World Health Organization (WHO) Research and Guideline Values for DBPs
The World Health Organization (WHO) International Agency for Research on Cancer (IARC) reviews research conducted on potential carcinogens and develops monographs that summarize the research and classify the compound. Links to the monographs for BDCM, DBCM, bromoform, and chloroform are available below (see Additional Resources(https://www.cdc.gov/safewater/chlorination-byproducts.html#resources) ). As can be seen in Table 1 (below), chloroform and BDCM are classified as possible human carcinogens. The classifications of possible human carcinogens come from data that is extrapolated from research on animals that may or may not be relevant to human cancer. DBCM and bromoform are not classifiable, indicating there is no evidence supporting these two compounds as carcinogens, but there is not enough research to classify them as non-carcinogenic. There is inadequate epidemiological evidence of carcinogenicity in humans for all four compounds.
Table 1: IARC Classification of THMs
Humans
Classification
Chloroform
Inadequate evidence for human carcinogenicity.
Possible human carcinogen (Group 2B)
Bromodichloromethane
Inadequate evidence for human carcinogenicity.
Possible human carcinogen (Group 2B)
Dibromochloromethane
Inadequate evidence for human carcinogenicity.
Not classifiable as to its carcinogenicity in humans (Group 3)
Bromoform
Inadequate evidence for human carcinogenicity.
Not classifiable as to its carcinogenicity in humans (Group 3)
WHO states that “all people, whatever their stage of development and their social and economic conditions, have the right to have access to an adequate supply of safe drinking water” . To this end, WHO has developed guideline values for many contaminants in drinking water. It is important to note that these guideline values are not standards. “It must be emphasized that the guideline values recommended are not mandatory limits. In order to define such limits, it is necessary to consider the guideline values in the context of local or national environmental, social, economic, and cultural conditions and waterborne disease occurrence” .
To develop the guideline values for drinking-water, WHO reviewed the literature for well-designed and documented studies showing health effects from exposure to each of the THMs . A safety factor of 1,000, an average adult human weight of 60 kilograms, and an average drinking water consumption of 2 liters per day were incorporated into the development of each guideline value. The chloroform, bromoform, and dibromochloromethane guideline values were all obtained using a total daily intake calculation. It was assumed that 50 percent of total daily intake of chloroform came from drinking water, and 20 percent of total daily intake of bromoform and dibromochloromethane came from drinking water (in areas with no showers, this assumption leads to a conservative estimate of risk). The models developed for bromodichloromethane and chloroform were based on an excess cancer risk of 10-5, or one extra cancer per 100,000 people at the guideline value for 70 years .
The chloroform guideline value was developed from a study showing hepatotoxicity in beagle dogs ingesting chloroform-laced toothpaste for 7.5 years. (A linearized multi-stage model based on observed increases in kidney tumors in male rats supports this total daily intake calculation).
The bromoform guideline value was developed from a study showing lesions on the livers of rats exposed to bromoform for 90 days.
The dibromochloromethane guideline value was developed based on the absence of histopathological effects in rats exposed for 90 days.
The bromodichloromethane guideline value was developed using a linearized multi-stage model based on observed increases in kidney tumors in male mice.
The WHO Guideline Values for the THMs are shown in Table 2. WHO also considers potential health effects caused by exposure to the four compounds simultaneously. In addition to the individual guidelines, there is an additional guideline that states the following: the sum of each individual THM concentration divided by its guideline value cannot be greater than one. This is depicted in the following equation:
Table 2: WHO Guideline Values for Trihalomethanes in Drinking Water (WHO, 1996)
WHO Guideline Value
Chloroform
200 μg/L
Bromodichloromethane
60 μg/L
Dibromochloromethane
100 μg/L
Bromoform
100 μg/L
These guidelines must be evaluated in context of the WHO Guidelines which state: "Infectious diseases caused by pathogenic bacteria, viruses, protozoa, and helminths are the most common and widespread health risk associated with drinking-water" (Chapter 7, Microbiological Aspects; Section 7.1, pg 118). Most importantly, the WHO specifically states in the 2nd edition of the Guidelines that: "Where local circumstances require that a choice must be made between meeting either microbiological guidelines or guidelines for disinfectants or disinfectant by-products, the microbiological quality must always take precedence, and where necessary, a chemical guideline value can be adopted corresponding to a higher level of risk. Efficient disinfection must never be compromised" (Chemical Aspects; Section 3.6.4, pg 49/65). In the 4th edition of the Guidelines, the WHO states: "In all circumstances, disinfection efficiency should not be compromised in trying to meet guidelines for DBPs, including chlorination by-products, or in trying to reduce concentrations of these substances" (Chapter 8 Chemical Aspects, Section 8.5.4, pg 188). Thus, waterborne pathogens pose a real and more immediate threat to health; water disinfection by-products are certainly the lesser of these two evils.
USEPA Standards for DBPs
The disinfectant/disinfection by-products (D/DBP) rule that regulates DBPs in the United States was designed to be implemented in three stages (Table 3) , . The US Environmental Protection Agency (USEPA) does not regulate THMs or HAAs individually – there is only a standard for total THMs and total HAAs.
Table 3: D/DBP Rule Implementation, USEPA
Stage
TTHM Standard
HAA Standard
Initial
100 μg/L
Stage 1
80 μg/L
60 μg/L
Stage 2
80 μg/L
60 μg/L
The USEPA has calculated cancer potency factors for the four THMs, which can be used to calculate the probability of cancer for varying exposure levels (Table 4). As can be seen, DBCM has the highest factor, and bromoform is an order of magnitude lower.
Table 4: USEPA Cancer Potency Factors
Compound
Cancer Potency Factor
Chloroform
insufficient data
Bromodichloromethane
0.062 mg/kg/day
Dibromochloromethane
0.084 mg/kg/day
Bromoform
0.0079 mg/kg/day
Thus, the extra cancer from chloroform was calculated to be negligible.
Other countries in the developed world, particularly in Europe, have established much stricter standards for DBPs in drinking water. These countries have the resources to follow the precautionary principle, which advocates the avoidance of chemicals until they are proven safe. These low standards are met, in part, by researching and implementing alternative disinfection methods (such as the use of ozone, UV light, and chloramines) and water treatment strategies (such as filtration before disinfection).
DBPs and the Safe Water System
Addition of chlorine to untreated water will lead to the formation of DBPs. A significant amount of energy and time has been invested in the United States and Europe to determine the human health effects of these DBPs and how to restructure water treatment processes to prevent DBP formation in order to minimize the slight risk of cancer from long-term exposure to DBPs. However, diarrheal disease in the developing world is still a leading cause of infant and under-5 mortality and morbidity. In these populations, the risk of death or delayed development in early childhood from diarrheal disease transmitted by contaminated water is far greater than the relatively small risk of cancer in old age.
CDC has tested Safe Water System water to measure the concentration of THMs in the finished water. In that study, household chlorination of turbid and non-turbid waters did not create THM concentrations that exceeded health risk guidelines , . In addition, ceramic filtration, sand filtration, cloth filtration, and settling and decanting were not effective mitigation strategies to reduce THM formation. Since this finding may not hold for all source waters worldwide, reducing organic matter in turbid source water may reduce the potential for DBP formation . To do this:
Let the water settle for 12-24 hours and then decant water into a second bucket. Chlorinate this decanted water, and/or
Filter the water through a cloth or filter before chlorination.
The Safe Water System is a proven intervention that consistently reduces diarrheal disease(https://www.cdc.gov/safewater/data/publications-by-topic.html#diarrheal) incidence among users in the developing world. This disease reduction leads to healthier children and adults. There is a slight risk to the ingestion of THMs at the WHO guideline value level. Although the risk from THMs is important to address, until centrally treated, piped water can be delivered to every family, the initial critical need is the provision of microbiologically safe drinking water to reduce the incidence of diarrhea and other waterborne disease.
If you have any questions or comments on this page or the Safe Water System, please email
References
White, G. The Handbook of Chlorination, 2nd Edition. Van Nostrand Reinhold Company, New York. 1986.
Gordon G, Cooper WJ, Rice RG, Pacey GE. Disinfectant residual measurement methods. AWWA Research Foundation, American Water Works Association. 1987.
Calderon RL. The epidemiology of chemical contaminants of drinking water. Food Chemical Toxicology. 2000;38:S13-S20.
Rook JJ. Formation of haloforms during chlorination of natural waters. Water Treatment Examination. 1974;23:234-243.
Richardson SD. The role of GC-MS and LC-MS in the discovery of drinking water disinfection by-products. Environmental Monitoring. 2002;4(1):1-9.
Lin, Tsair-Fuh, Shih-Wen Hoang. Inhalation exposure to THMs from drinking water in south Taiwan. Science Total Environment. 2000;246:41-49.
Backer, LC, Ashley DL, Bonin MA, Cardinali FL, Kieszak SM, and Wooten JV. Household exposures to drinking water disinfection by-products: whole blood trihalomethanes levels. J Expo Anal Environ Epidemiology. 2000;July-August 10(4); 321-6.
WHO. Guidelines for drinking-water quality, 2nd edition, Volume 2: Health Criteria and other supporting information[PDF – 94 pages]. World Health Organization, Geneva. 1996.
WHO. Guidelines for drinking-water quality, 2nd edition, Volume 1: Recommendations. World Health Organization, Geneva. 1993.
WHO. Guidelines for drinking-water quality, 4th edition. World Health Organization, Geneva. 2011.
EPA. National primary drinking water standards.
EPA. Comprehensive disinfectants and disinfection byproducts rules (Stage 1 and Stage 2): Quick reference guide. 2010.
EPA. Integrated Risk Information System.
Lantagne DS, Blount BC, Cardinali F, Quick R. Disinfection by-product formation and mitigation strategies in point-of-use chlorination of turbid and non-turbid waters in western Kenya. J Water Health. 2008;6(1):67-82.
Lantagne DS, Cardinali F, Blount BC. Disinfection by-product formation and mitigation strategies in point-of-use chlorination with sodium dichloroisocyanurate in Tanzania. Am J Trop Med Hyg. 2010;83(1):135-43.
The sulfur cycle is the collection of processes by which sulfur moves to and from minerals (including the waterways) and living systems. Such biogeochemical cycles are important in geology because they affect many minerals.
Sulfur (S), the tenth most abundant element in the universe, is a brittle, yellow, tasteless, and odorless non-metallic element. It comprises many vitamins, proteins, and hormones that play critical roles in both climate and in the health of various ecosystems. The majority of the Earth’s sulfur is stored underground in rocks and minerals, including as sulfate salts buried deep within ocean sediments.
The sulfur cycle contains both atmospheric and terrestrial processes. Within the terrestrial portion, the cycle begins with the weathering of rocks, releasing the stored sulfur. The sulfur then comes into contact with air where it is converted into sulfate (SO4). The sulfate is taken up by plants and microorganisms and is converted into organic forms; animals then consume these organic forms through foods they eat, thereby moving the sulfur through the food chain. As organisms die and decompose, some of the sulfur is again released as a sulfate and some enters the tissues of microorganisms. There are also a variety of natural sources that emit sulfur directly into the atmosphere, including volcanic eruptions, the breakdown of organic matter in swamps and tidal flats, and the evaporation of water.
Sulfur eventually settles back into the Earth or comes down within rainfall. A continuous loss of sulfur from terrestrial ecosystem runoff occurs through drainage into lakes and streams, and eventually oceans. Sulfur also enters the ocean through fallout from the Earth’s atmosphere. Within the ocean, some sulfur cycles through marine communities, moving through the food chain. A portion of this sulfur is emitted back into the atmosphere from sea spray. The remaining sulfur is lost to the ocean depths, combining with iron to form ferrous sulfide which is responsible for the black color of most marine sediments.
Since the Industrial Revolution, human activities have contributed to the amount of sulfur that enters the atmosphere, primarily through the burning of fossil fuels and the processing of metals. One-third of all sulfur that reaches the atmosphere—including 90% of sulfur dioxide—stems from human activities. Emissions from these activities, along with nitrogen emissions, react with other chemicals in the atmosphere to produce tiny particles of sulfate salts which fall as acid rain, causing a variety of damage to both the natural environment as well as to man-made environments, such as the chemical weathering of buildings. However, as particles and tiny airborne droplets, sulfur also acts as a regulator of global climate. Sulfur dioxide and sulfate aerosols absorb ultraviolet radiation, creating cloud cover that cools cities and may offset global warming caused by the greenhouse effect.
Graphene inspires atom-thin acolyte made from pure boron.
Meet flatland’s latest resident: borophene, a sheet of boron just one atom thick. It joins a family of two-dimensional materials that has been flourishing ever since graphene, the granddaddy of them all, took the world by storm in 2004.
Graphene’s honeycomb arrangement of carbon atoms lends it strength, flexibility and superb electrical conductivity. Borophene’s boron atoms share the same arrangement, but with an extra boron atom cherried on top of each tessellated hexagon. And although borophene has not yet been isolated as a free-standing sheet, there are already tantalizing hints that some of borophene’s properties could surpass those of its flat cousins. “Borophene is just beginning to be studied,” says Mark Hersam, a materials scientist at Northwestern University in Evanston, Illinois, and part of the team that unveiled the material in Science on 17 December1. “It’s good to get it out there so the field as a whole can take it on — there’s so much to be done with it.” Earning its stripes Hersam and his colleagues grew borophene on silver, by evaporating boron atoms from a solid boron rod at temperatures of 450ºC to 700ºC inside an ultrahigh-vacuum chamber. Whereas boron itself is a poor electrical conductor, the team found that borophene is fully metallic. Unprotected samples oxidized in a few hours, but a silicon covering kept them stable for several weeks. “I was delighted to see this result,” says Deji Akinwande, a nanomaterials researcher at the University of Texas at Austin. “It’s quite different from other 2D materials, which are mostly semiconductors.” Images under a scanning tunnelling microscope revealed that borophene could take different forms, depending on the temperature used to make it and on how the atoms of boron sat on the silver below. One looked smooth, while the other appeared stripy, with corrugations like the ridges and furrows of a ploughed field. Calculations suggest that corrugated borophene conducts electricity much better along these ridges than across them; it could even be stiffer and more conductive in this direction than is graphene. Hersam’s team is now trying to measure these qualities experimentally, and he says that their directionality could give borophene an advantage in certain applications, such as a switchable filter for polarized light. Chemical exuberance “The next fundamental challenge is to demonstrate a free-standing sheet of this material,” says Akinwande. “That really opens up the science and engineering opportunities.” Transferring free-standing borophene to an insulating substrate would allow researchers to accurately measure its conductivity, for example. But that’s far from trivial: “Boron reacts with almost everything around it,” says Hermann Sachdev, an inorganic chemist at the Technical University of Kaiserslautern in Germany. Boron's reactivity may turn out to be an advantage, however, because borophene could be readily modified with other chemical groups or sandwiched between other materials to fine-tune its properties. Boron and many of its compounds are also extremely hard, so if borophene’s chemical exuberance can be controlled it might be easier to handle than more fragile flatlanders such as silicene or germanene (2D sheets of silicon and germanium, respectively). “I expect folks working on silicene may pivot to this,” says Hersam. Back in February, Akinwande made the first silicene transistor2, and says that he would like to study borophene as well, if he can get the funding. Measurements by Hersam’s team suggest that borophene has a higher electron density than graphene, and Akinwande says that this raises the possibility that cooled borophene could act as a superconductor, carrying electrical charge with no resistance. Borophene may even point the way to the next 2D material. Aluminium is immediately below boron in the periodic table, and a theoretical study has predicted that it could form atom-thin honeycomb sheets of aluminene3. If that material could be created in the lab, says Akinwande, its conductivity might overshadow both graphene's and borophene's. Nature doi:10.1038/nature.2015.19060 http://www.nature.com/…/atom-thin-borophene-joins-2d-materi…
Lithium aluminium hydride, commonly abbreviated to LAH, is an inorganic compound with the chemical formula LiAlH4. It was discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters, carboxylic acids, and amides. The solid is dangerously reactive toward water, releasing gaseous hydrogen (H2). Some related derivatives have been discussed for hydrogen storage.
LAH is a colorless solid, but commercial samples are usually gray due to contamination.This material can be purified by recrystallization from diethyl ether. Large-scale purifications employ a Soxhlet extractor. Commonly, the impure gray material is used in synthesis, since the impurities are innocuous and can be easily separated from the organic products. The pure powdered material is pyrophoric, but not its large crystals. Some commercial materials contain mineral oil to inhibit reactions with atmospheric moisture, but more commonly it is packed in moisture-proof plastic sacks.
LAH
violently reacts with water, including atmospheric moisture. The
reaction proceeds according to the following idealized equation: LiAlH4 + 4 H2O → LiOH + Al(OH)3 + 4 H2
This reaction provides a useful method to generate hydrogen in the laboratory. Aged, air-exposed samples often appear white because they have absorbed enough moisture to generate a mixture of the white compounds lithium hydroxide and aluminium hydroxide. LAH crystallizes in the monoclinic space group P21/c. The unit cell has the dimensions: a = 4.82, b = 7.81, and c = 7.92 Å, α = γ=90° and β=112°. In the structure, Li+ centers are surrounded by five AlH−4 tetrahedra. The Li+ centers are bonded to one hydrogen atom from each of the surrounding tetrahedra creating a bipyramid arrangement. At high pressures (>2.2 GPa) a phase transition may occur to give β-LAH. X-ray powder diffraction pattern of as-received LiAlH4. The asterisk designates an impurity, possibly LiCl. Preparation LiAH was first prepared from the reaction between lithium hydride (LiH) and aluminium chloride:
4 LiH + AlCl3 → LiAlH4 + 3 LiCl
In addition to this method, the industrial synthesis entails the initial preparation of sodium aluminium hydride from the elements under high pressure and temperature:
Na + Al + 2 H2 → NaAlH4
LiAlH4 is then prepared by a salt metathesis reaction according to:
NaAlH4 + LiCl → LiAlH4 + NaCl
which proceeds in a high yield of LAH. LiCl is removed by filtration from an ethereal solution of LiAH, with subsequent precipitation of LiAH to yield a product containing around 1% w/w LiCl.
More than 80 years after it was first predicted scientists at Harvard turned hydrogen into metal, and it could revolutionize our planet.
They did it by subjecting hydrogen to extremely high pressures, which changed it from a liquid to a solid.
The resulting material could be used as a superconductor, which would work at room temperature.
This would save lots of energy and money because current superconductors only work at below -269°C.
It could also be used to make MRI scanners and power lines cheaper and more efficient too.
In 1935, scientists predicted that the element hydrogen could become a metal if subjected to enough pressure. Teams have been attempting to confirm the prediction ever since, but have not been able to construct a vise capable of squeezing the element enough without breaking the equipment.
But a team of scientists at Harvard University published a paper this week in the peer-reviewed journalSciencesaying they managed to squeeze hydrogen in a diamond vise to the point that the element became reflective, a key property of metals.
The study is not merely a parlor trick. Metallic hydrogen is thought to be a superconductor, meaning it could conduct electricity without any resistance. Electricity traveling through normal circuits loses energy to resistance over time, often in the form of heat. This is why it is harder to send electrical currents (say, through the electricity grid) over long distances than short ones. But a current traveling through a superconducting material loses nearly zero energy.
Superconductive metals are used to make the magnets for devices such as hospital MRI machines and particle accelerators such as CERN. The trouble with many superconductors is that the materials now used need to be cooled to extremely low temperatures in order to work, which is expensive.
It is also possible that metallic hydrogen material may be "metastable," according to Science Magazine. This means that, once formed, it may retain its metallic properties even at normal temperatures and pressure levels, like diamonds. If so, it could conduct electricity at nearly 100 percent efficiency in normal conditions. Again, this could dramatically reduce the costs of transferring electrical currents, meaning more powerful and efficient electric motors, and a far more efficient electrical grid.
Scientists have been searching for such a material almost as long as they have known about superconductivity.
Of course, the study has its critics. Eugene Gregoryanz, a physicist at the University of Edinburgh, toldScience Magazinehe sees a several problems with the experiment's procedures.
"The word garbage cannot really describe it," said Gregoryanz, of the experiment.
The video below, from Harvard, discusses the discovery in detail:
