Unique Meteor Stone Amazes Scientists

Extra-Terrestrial Hypatia Stone Rattles Solar System Status Quo
Date:
January 9, 2018

Source:

University of Johannesburg as compiled by Science Daily

Summary:

Analyses on a small pebble found in south-west Egypt cast significant questions on a widely-held view about the primitive pre-solar dust cloud which our Sun, Earth and other planets were formed from. Researchers found exotic micro-mineral compounds in the 'Hypatia' stone that are not known to occur on Earth, elsewhere in our solar system, or in known meteorites or comets.

In 2013, researchers announced that a pebble found in south-west Egypt, was definitely not from Earth. By 2015, other research teams had announced that the 'Hypatia' stone was not part of any known types of meteorite or comet, based on noble gas and nuclear probe analyses.

(The stone was named Hypatia after Hypatia of Alexandria, the first Western woman mathematician and astronomer.)

However, if the pebble was not from Earth, what was its origin and could the minerals in it provide clues on where it came from? Micro-mineral analyses of the pebble by the original research team at the University of Johannesburg have now provided unsettling answers that spiral away from conventional views of the material our solar system was formed from.

Mineral structure

The internal structure of the Hypatia pebble is somewhat like a fruitcake that has fallen off a shelf into some flour and cracked on impact, says Prof Jan Kramers, lead researcher of the study published in Geochimica et Cosmochimica Acta on 28 Dec 2017.

"We can think of the badly mixed dough of a fruit cake representing the bulk of the Hypatia pebble, what we called two mixed 'matrices' in geology terms. The glace cherries and nuts in the cake represent the mineral grains found in Hypatia 'inclusions'. And the flour dusting the cracks of the fallen cake represent the 'secondary materials' we found in the fractures in Hypatia, which are from Earth," he says.

The original extraterrestrial rock that fell to Earth must have been at least several meters in diameter, but disintegrated into small fragments of which the Hypatia stone is one.

Weird matrix

Straight away, the Hypatia mineral matrix (represented by fruitcake dough), looks nothing like that of any known meteorites, the rocks that fall from space onto Earth every now and then.

"If it were possible to grind up the entire planet Earth to dust in a huge mortar and pestle, we would get dust with on average a similar chemical composition as chondritic meteorites," says Kramers. "In chondritic meteorites, we expect to see a small amount of carbon{C} and a good amount of silicon (Si). But Hypatia's matrix has a massive amount of carbon and an unusually small amount of silicon."

"Even more unusual, the matrix contains a high amount of very specific carbon compounds, called polyaromatic hydrocarbons, or PAH, a major component of interstellar dust, which existed even before our solar system was formed. Interstellar dust is also found in comets and meteorites that have not been heated up for a prolonged period in their history," adds Kramers.

In another twist, most (but not all) of the PAH in the Hypatia matrix has been transformed into diamonds smaller than one micrometer, which are thought to have been formed in the shock of impact with the Earth's atmosphere or surface. These diamonds made Hypatia resistant to weathering so that it is preserved for analysis from the time it arrived on Earth.

Weirder grains never found before

When researcher Georgy Belyanin analyzed the mineral grains in the inclusions in Hypatia, (represented by the nuts and cherries of a fruitcake), a number of most surprising chemical elements showed up.

"The aluminum occurs in pure metallic form, on its own, not in a chemical compound with other elements. As a comparison, gold occurs in nuggets, but aluminum never does. This occurrence is extremely rare on Earth and the rest of our solar system, as far as is known in science," says Belyanin.

"We also found silver iodine phosphide and moissanite (silicon carbide) grains, again in highly unexpected forms. The grains are the first documented to be found in situ (as is) without having to first dissolve the surrounding rock with acid," adds Belyanin. "There are also grains of a compound consisting of mainly nickel and phosphorus, with very little iron; a mineral composition never observed before on Earth or in meteorites," he adds.

Dr Marco Andreoli, a Research Fellow at the School of Geosciences at the University of the Witwatersrand, and a member of the Hypatia research team says, "When Hypatia was first found to be extraterrestrial, it was a sensation, but these latest results are opening up even bigger questions about its origins."

Unique minerals in our solar system

Taken together, the ancient unheated PAH carbon as well as the phosphides, the metallic aluminum, and the moissanite suggest that Hypatia is an assembly of unchanged pre-solar material. That means, matter that existed in space before our Sun, the Earth and the other planets in our solar system were formed.

Supporting the pre-solar concept is the weird composition of the nickel-phosphorus-iron grains found in the Hypatia inclusions. These three chemical elements are interesting because they belong to the subset of chemical elements heavier than carbon and nitrogen which form the bulk of all the rocky planets.

"In the grains within Hypatia the ratios of these three elements to each other are completely different from that calculated for the planet Earth or measured in known types of meteorites. As such these inclusions are unique within our solar system," adds Belyanin.

"We think the nickel-phosphorus-iron grains formed pre-solar, because they are inside the matrix, and are unlikely to have been modified by shock such as collision with the Earth's atmosphere or surface, and also because their composition is so alien to our solar system," he adds.

"Was the bulk of Hypatia, the matrix, also formed before our solar system? Probably not, because you need a dense dust cloud like the solar nebula to coagulate large bodies" he says.

A different kind of dust

Generally, science says that our solar system's planets ultimately formed from a huge, ancient cloud of interstellar dust (the solar nebula) in space. The first part of that process would be much like dust bunnies coagulating in an unswept room. Science also holds that the solar nebula was homogenous, that is, the same kind of dust everywhere.

But Hypatia's chemistry tugs at this view. "For starters, there are no silicate minerals in Hypatia's matrix, in contrast to chondritic meteorites (and planets like the Earth, Mars and Venus), where silicates are dominant. Then there are the exotic mineral inclusions. If Hypatia itself is not presolar, both features indicate that the solar nebula wasn't the same kind of dust everywhere -- which starts tugging at the generally accepted view of the formation of our solar system," says Kramers.

Into the future

"What we do know is that Hypatia was formed in a cold environment, probably at temperatures below that of liquid nitrogen on Earth (-196 Celsius). In our solar system it would have been way further out than the asteroid belt between Mars and Jupiter, where most meteorites come from. Comets come mainly from the Kuiper Belt, beyond the orbit of Neptune and about 40 times as far away from the sun as we are. Some come from the Oort Cloud, even further out. We know very little about the chemical compositions of space objects out there. So our next question will dig further into where Hypatia came from," says Kramers.

The little pebble from the Libyan Desert Glass strewn field in south-west Egypt presents a tantalizing piece for an extraterrestrial puzzle that is getting ever more complex.

The research was funded by University of Johannesburg Research council via the PPM Research Centre.

The researchers would like to thank Aly Barakat, Mario di Martino and Romano Serra for access to the Hypatia sample material; and Michael Wiedenbeck and his co-workers at the Geoforschungszentrum Potsdam, Germany for their collaboration.

https://www.sciencedaily.com/releases/2018/01/180109112437.htm

Right Exercises Slow Heart Aging

Proper Exercise Can Reduce
Damage from Heart Aging

DALLAS – Jan. 8, 2018 – Exercise can reverse damage to sedentary, aging hearts and help prevent risk of future heart failure – if it’s enough exercise, and if it’s begun in time, according to a new study by cardiologists at UT Southwestern and Texas Health Resources.

To reap the most benefit, the exercise regimen should begin by late middle age (before age 65), when the heart apparently retains some plasticity and ability to remodel itself, according to the findings by researchers at the Institute for Exercise and Environmental Medicine (IEEM), which is a collaboration between UT Southwestern Medical Center and Texas Health Presbyterian Hospital Dallas.

And the exercise needs to be performed four to five times a week. Two to three times a week was not enough, the researchers found in an earlier study.

 “Based on a series of studies performed by our team over the past 5 years, this ‘dose’ of exercise has become my prescription for life,” said senior author Dr. Benjamin Levine, Director of the Institute and Professor of Internal Medicine at UT Southwestern. “I think people should be able to do this as part of their personal hygiene – just like brushing your teeth and taking a shower.”

The regimen included exercising four to five times a week, generally in 30-minute sessions, plus warmup and cool-down:  

• One of the weekly sessions included a high-intensity 30-minute workout, such as aerobic interval sessions in which heart rate tops 95 percent of peak rate for 4 minutes, with 3 minutes of recovery, repeated four times (a so-called “4x4”).
• Each interval session was followed by a recovery session performed at relatively low intensity.
• One day’s session lasted an hour and was of moderate intensity. (As a “prescription for life,” Levine said this longer session could be a fun activity such as tennis, aerobic dancing, walking, or biking.)
• One or two other sessions were performed each week at a moderate intensity, meaning the participant would break a sweat, be a little short of breath, but still be able to carry on a conversation – the “talk test.” In the study, exercise sessions were individually prescribed based on exercise tests and heart rate monitoring.
• One or two weekly strength training sessions using weights or exercise machines were included on a separate day, or after an endurance session.

·         Study participants built up to those levels, beginning with three, 30-minute, moderate exercise sessions for the first 3 months and peaked at 10 months when two high-intensity aerobic intervals were added.

The more than 50 participants in the study were divided into two groups, one of which received two years of supervised exercise training and the other group, a control group, which participated in yoga and balance training.

At the end of the two-year study, those who had exercised showed an 18 percent improvement in their maximum oxygen intake during exercise and a more than 25 percent improvement in compliance, or elasticity, of the left ventricular muscle of the heart, Dr. Levine noted. He compared the change in the heart to a stretchy, new rubber band versus one that has gotten stiff sitting in a drawer.

Sedentary aging can lead to a stiffening of the muscle in the heart’s left ventricle, the chamber that pumps oxygen-rich blood back out to the body, he explained.

“When the muscle stiffens, you get high pressure and the heart chamber doesn’t fill as well with blood.  In its most severe form, blood can back up into the lungs. That’s when heart failure develops,” said Dr. Levine, who holds the S. Finley Ewing Chair for Wellness at Texas Health Dallas and the Harry S. Moss Heart Chair for Cardiovascular Research. He also holds the Distinguished Professorship in Exercise Sciences at UT Southwestern, which is celebrating its 75^th anniversary this year. 

Earlier research by UT Southwestern cardiologists showed that left ventricular stiffening often shows up in middle age in people who don’t exercise and aren’t fit, leaving them with small, stiff chambers that can’t pump blood as well.

However, the researchers also found that the heart chamber in competitive masters-level athletes remains large and elastic, and that even four to five days of committed exercise over decades is enough for noncompetitive athletes to reap most of this benefit.

In the current study, researchers wanted to know if exercise can restore the heart’s elasticity in previously sedentary individuals – especially if begun in late middle age. Previous studies from Dr. Levine’s research program have shown substantial improvements in cardiac compliance in young individuals after a year of training, but surprisingly little change if the training was started after age 65.

To start the study, researchers recruited 53 participants, ages 45 to 64. Many came from the Dallas Heart Study, which includes 6,000 Dallas residents and is the only single-center heart study of its size and multiethnic composition. The Dallas Heart Study is designed to improve the diagnosis, prevention, and treatment of heart disease.

The new study appears in Circulation, a journal of the American Heart Association. Collaborators on the study included first author Dr. Erin Howden, Research Fellow with UT Southwestern’s Graduate School of Biomedical Sciences and the IEEM and now a faculty member at the Baker Heart and Diabetes Institute in Melbourne, Australia. Funding came from the National Institutes of Health and the American Heart Association.

http://www.utsouthwestern.edu/newsroom/articles/year-2018/exercise-aging-heart.html

Exceptionally Strong Ultrafine Fibers

New technique developed at MIT could produce strong, resilient nanofibers for many applications.
By David L. Chandler | MIT News Office

January 4, 2018 -- Researchers at MIT have developed a process that can produce ultrafine fibers — whose diameter is measured in nanometers, or billionths of a meter — that are exceptionally strong and tough. These fibers, which should be inexpensive and easy to produce, could be choice materials for many applications, such as protective armor and nanocomposites.

The new process, called gel electrospinning, is described in a paper by MIT professor of chemical engineering Gregory Rutledge and postdoc Jay Park. The paper appears online and will be published in the February edition of the Journal of Materials Science.

In materials science, Rutledge explains, “there are a lot of tradeoffs.” Typically researchers can enhance one characteristic of a material but will see a decline in a different characteristic. “Strength and toughness are a pair like that: Usually when you get high strength, you lose something in the toughness,” he says. “The material becomes more brittle and therefore doesn’t have the mechanism for absorbing energy, and it tends to break.” But in the fibers made by the new process, many of those tradeoffs are eliminated.

“It’s a big deal when you get a material that has very high strength and high toughness,” Rutledge says. That’s the case with this process, which uses a variation of a traditional method called gel spinning but adds electrical forces. The results are ultrafine fibers of polyethylene that match or exceed the properties of some of the strongest fiber materials, such as Kevlar and Dyneema, which are used for applications including bullet-stopping body armor.

“We started off with a mission to make fibers in a different size range, namely below 1 micron [millionth of a meter], because those have a variety of interesting features in their own right,” Rutledge says. “And we’ve looked at such ultrafine fibers, sometimes called nanofibers, for many years. But there was nothing in what would be called the high-performance fiber range.” High-performance fibers, which include aramids such as Kevlar, and gel spun polyethylenes like Dyneema and Spectra, are also used in ropes for extreme uses, and as reinforcing fibers in some high-performance composites.

“There hasn’t been a whole lot new happening in that field in many years, because they have very top-performing fibers in that mechanical space,” Rutledge says. But this new material, he says, exceeds all the others. “What really sets those apart is what we call specific modulus and specific strength, which means that on a per-weight basis they outperform just about everything.” Modulus refers to how stiff a fiber is, or how much it resists being stretched.

Compared to carbon fibers and ceramic fibers, which are widely used in composite materials, the new gel-electrospun polyethylene fibers have similar degrees of strength but are much tougher and have lower density. That means that, pound for pound, they outperform the standard materials by a wide margin, Rutledge says.

In creating this ultrafine material, the team had aimed just to match the properties of existing microfibers, “so demonstrating that would have been a nice accomplishment for us,” Rutledge says. In fact, the material turned out to be better in significant ways. While the test materials had a modulus not quite as good as the best existing fibers, they were quite close — enough to be “competitive,” he says. Crucially, he adds, “the strengths are about a factor of two better than the commercial materials and comparable to the best available academic materials. And their toughness is about an order of magnitude better.”

The researchers are still investigating what accounts for this impressive performance. “It seems to be something that we received as a gift, with the reduction in fiber size, that we were not expecting,” Rutledge says.

He explains that “most plastics are tough, but they’re not as stiff and strong as what we’re getting.” And glass fibers are stiff but not very strong, while steel wire is strong but not very stiff. The new gel-electrospun fibers seem to combine the desirable qualities of strength, stiffness, and toughness in ways that have few equals.

Using the gel electrospinning process “is essentially very similar to the conventional [gel spinning] process in terms of the materials we’re bringing in, but because we’re using electrical forces” and using a single-stage process rather than the multiple stages of the conventional process, “we are getting much more highly drawn fibers,” with diameters of a few hundred nanometers rather than the typical 15 micrometers, he says. The researchers’ process combines the use of a polymer gel as the starting material, as in gel spun fibers, but uses electrical forces rather than mechanical pulling to draw the fibers out; the charged fibers induce a “whipping” instability process that produces their ultrafine dimensions. And those narrow dimensions, it turns out, led to the unique properties of the fibers.

These results might lead to protective materials that are as strong as existing ones but less bulky, making them more practical. And, Rutledge adds, “they may have applications we haven’t thought about yet, because we’ve just now learned that they have this level of toughness.”

The research was supported by the U.S. Army through the Natick Soldier Research, Development and Engineering Center, and the Institute for Soldier Nanotechnologies, and by the National Science Foundation’s Center for Materials Science and Engineering.

http://news.mit.edu/2018/ultrafine-fibers-have-exceptional-strength-0105

Basic Facts About Dental Implants

A dental implant (also known as an endosseous implant or fixture) is a surgical component that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biologic process called osseointegration, in which materials such as titanium form an intimate bond to bone. The implant fixture is first placed so that it is likely to osseointegrate, then a dental prosthetic is added. A variable amount of healing time is required for osseointegration before either the dental prosthetic (a tooth, bridge or denture) is attached to the implant or an abutment is placed which will hold a dental prosthetic.

                                                           single crown dental implant

Success or failure of implants depends on the health of the person receiving the treatment, drugs which affect the chances of osseointegration, and the health of the tissues in the mouth. The amount of stress that will be put on the implant and fixture during normal function is also evaluated. Planning the position and number of implants is key to the long-term health of the prosthetic since biomechanical forces created during chewing can be significant. The position of implants is determined by the position and angle of adjacent teeth, by lab simulations or by using computed tomography with CAD/CAM simulations and surgical guides called stents. The prerequisites for long-term success of osseointegrated dental implants are healthy bone and gingiva. Since both can atrophy after tooth extraction, pre-prosthetic procedures such as sinus lifts or gingival grafts are sometimes required to recreate ideal bone and gingiva.

The final prosthetic can be either fixed, where a person cannot remove the denture or teeth from their mouth, or removable, where they can remove the prosthetic. In each case an abutment is attached to the implant fixture. Where the prosthetic is fixed, the crown, bridge or denture is fixed to the abutment either with lag screws or with dental cement. Where the prosthetic is removable, a corresponding adapter is placed in the prosthetic so that the two pieces can be secured together.

The risks and complications related to implant therapy divide into those that occur during surgery (such as excessive bleeding or nerve injury), those that occur in the first six months (such as infection and failure to osseointegrate) and those that occur long-term (such as peri-implantitis and mechanical failures). In the presence of healthy tissues, a well-integrated implant with appropriate biomechanical loads can have 5-year plus survival rates from 93 to 98 percent and 10 to 15 year lifespans for the prosthetic teeth. Long-term studies show a 16- to 20-year success (implants surviving without complications or revisions) between 52% and 76%, with complications occurring up to 48% of the time.

https://en.wikipedia.org/wiki/Dental_implant

Explorer Jedediah Smith

Jedediah Strong Smith (January 6, 1799 – May 27, 1831), was a clerk, frontiersman, hunter, trapper, author, cartographer, and explorer of the Rocky Mountains, the North American West, and the Southwest during the early 19th century. After 75 years of obscurity following his death, Smith was rediscovered as the American whose explorations led to the use of the 20-mile (32 km)-wide South Pass as the dominant point of crossing the Continental Divide for pioneers on the Oregon Trail.

                                                          A Portrait of Jedediah Smith 

Coming from a modest family background, Smith traveled to St. Louis and joined William H. Ashley and Andrew Henry's fur trading company in 1822. Smith led the first documented exploration from the Salt Lake frontier to the Colorado River. From there, Smith's party became the first white Americans to cross the Mojave Desert into California. On the return journey, Smith and his companions were the first United States citizens to explore and eastwardly cross the Sierra Nevada and the treacherous Great Basin Desert. Smith and his companions were also the first white Americans to travel up the California coast (on land) to reach the Oregon Country. Surviving three Indian massacres and one bear mauling, Jedediah Smith's explorations and documented travels were important resources to later American westward expansion.

In March 1831, while in St. Louis, Smith requested of Secretary of War John H. Eaton a federally funded exploration of the West, but to no avail. Smith informed Eaton that he was completing a map of the West derived from his own journeys. In May, Smith and his partners launched a planned para-military trading party to Santa Fe. On May 27, while searching for water in present-day southwest Kansas, Smith went missing. It was learned some weeks later that he had been killed during an encounter with the Comanche, while his body was never recovered.

After his death, Smith's memory and his accomplishments were mostly forgotten by Americans. At the beginning of the 20th century, scholars and historians made efforts to recognize and study his achievements. In 1918, a book by Harrison Clifford Dale was published covering Ashley-Smith western explorations. In 1935, Smith's summary autobiography was finally listed in a biographical dictionary. Smith's first comprehensive biography by Maurice S. Sullivan was published in 1936. A popular Smith biography by Dale Morgan, published in 1953, established Smith as an authentic national hero. Smith's map of the West in 1831 was superimposed by the U.S. Army and later used by western explorer John C. Frémont during the early 1840s.

https://en.wikipedia.org/wiki/Jedediah_Smith

Massive Stars Near Milky Way

Weighing Massive Stars in Nearby Galaxy Reveals an Excess of Heavyweights

University of Oxford, January 4, 2018 -- Astronomers have revealed an 'astonishing' overabundance of massive stars in a neighboring galaxy. The discovery, made in the gigantic star-forming region 30 Doradus in the Large Magellanic Cloud galaxy, has 'far-reaching' consequences for our understanding of how stars transformed the pristine Universe into the one we live in today.

The discovery, made in the gigantic star-forming region 30 Doradus in the Large Magellanic Cloud galaxy, has 'far-reaching' consequences for our understanding of how stars transformed the pristine Universe into the one we live in today.

The results are published in the journal Science.

Lead author Fabian Schneider, a Hintze Research Fellow in the University of Oxford's Department of Physics, said: 'We were astonished when we realised that 30 Doradus has formed many more massive stars than expected.'

As part of the VLT-FLAMES Tarantula Survey (VFTS), the team used ESO's Very Large Telescope to observe nearly 1,000 massive stars in 30 Doradus, a gigantic stellar nursery also known as the Tarantula nebula. The team used detailed analyses of about 250 stars with masses between 15 and 200 times the mass of our Sun to determine the distribution of massive stars born in 30 Doradus -- the so-called initial mass function (IMF).

Massive stars are particularly important for astronomers because of their enormous influence on their surroundings (known as their 'feedback'). They can explode in spectacular supernovae at the end of their lives, forming some of the most exotic objects in the Universe -- neutron stars and black holes.

Co-author Hugues Sana from the University of Leuven in Belgium said: 'We have not only been surprised by the sheer number of massive stars, but also that their IMF is densely sampled up to 200 solar masses.' Until recently, the existence of stars up to 200 solar masses was highly disputed, and the study shows that a maximum birth mass of stars of 200-300 solar masses appears likely.

In most parts of the Universe studied by astronomers to date, stars become rarer the more massive they are. The IMF predicts that most stellar mass is in low-mass stars and that less than 1% of all stars are born with masses in excess of ten times that of the Sun. Measuring the proportion of massive stars is extremely difficult -- primarily because of their scarcity -- and there are only a handful of places in the local Universe where this can be done.

The team turned to 30 Doradus, the biggest local star-forming region, which hosts some of the most massive stars ever found, and determined the masses of massive stars with unique observational, theoretical and statistical tools. This large sample allowed the scientists to derive the most accurate high-mass segment of the IMF to date, and to show that massive stars are much more abundant than previously thought. Chris Evans from the Science and Technology Facilities Council's UK Astronomy Technology Centre, the principal investigator of VFTS and a co-author of the study, said: 'In fact, our results suggest that most of the stellar mass is actually no longer in low-mass stars, but a significant fraction is in high-mass stars.'

Stars are cosmic engines and have produced most chemical elements heavier than helium, from the oxygen we breathe every day to the iron in our blood. During their lives, massive stars produce copious amounts of ionising radiation and kinetic energy through strong stellar winds. The ionising radiation of massive stars was crucial for the re-brightening of the Universe after the so-called Dark Ages, and their mechanical feedback drives the evolution of galaxies. Philipp Podsiadlowski, a co-author of the study from the University of Oxford, said: 'To quantitatively understand all these feedback mechanisms, and hence the role of massive stars in the Universe, we need to know how many of these behemoths are born.'

Fabian Schneider added: 'Our results have far-reaching consequences for the understanding of our cosmos: there might be 70% more supernovae, a tripling of the chemical yields and towards four times the ionising radiation from massive star populations. Also, the formation rate of black holes might be increased by 180%, directly translating into a corresponding increase of binary black hole mergers that have recently been detected via their gravitational wave signals.'

The team's research leaves many open questions, which they intend to investigate in the future: how universal are the findings, and what are the consequences of this for the evolution of our cosmos and the occurrence of supernovae and gravitational wave events?

From:  University of Oxford. "Weighing massive stars in nearby galaxy reveals excess of heavyweights." ScienceDaily, 4 January 2018. https://www.sciencedaily.com/releases/2018/01/180104153159.htm

Petty College Physics Lab Work

Research Reveals ‘Shocking’
Weakness of Lab Courses
By Daryl Lovell

ITHACA, N.Y. – January 2, 2018 -- With the new emphasis on hands-on, active learning throughout higher education, lab courses would seem to have an advantage – what could be more active than doing experiments? But surprising new research reveals traditional labs fall far short of their pedagogical goals.

In a paper published Jan. 2 in Physics Today, “Introductory Physics Labs: We Can Do Better,” Natasha Holmes, Cornell assistant professor of physics, and Nobel laureate Carl Wieman of Stanford University report on their analysis of nine introductory physics laboratory courses at three institutions, taught by seven instructors and involving almost 3,000 students. The labs were all designed to support student learning of the associated lecture course content. Because the lab sections were optional, the researchers could compare outcomes with a control group of students who did not take the lab courses.

The results were so consistent, and so abysmal, that the researchers call it “shocking.” They write that “with a high degree of precision, there was no statistically measurable lab benefit. … None of the mean effects was larger than 2 percent statistically; they were all indistinguishable from zero.”

Even when the researchers restricted their analysis to exam questions that didn’t require quantitative calculations, but only conceptual reasoning that should have been enhanced in a lab course, they got the same results for the lab benefit: zero.

Lab courses are supposed to enable students to see how physics principles work in real life; conducting experiments should help them understand physics better and reinforce classroom instruction. Why is this not happening?

“Although one may think that labs are inherently active, our research shows that in traditional labs students may be active with their hands but they’re not really active with their brains,” says Holmes. “Following rote procedures to get a proscribed outcome at the end isn’t doing a whole lot.”

In extensive interviews with students, Holmes and Wieman write that they found, “the only thinking the students said they did in structured and content-focused labs … was in analyzing data and checking whether it was feasible to finish the lab in time.”

In a typical lab activity, “the relevant equations and principles are laid out in the preamble; students are told what value they should get for a particular measurement or given the equation to predict that value; they are told what data to collect and how to collect them; and often they are even told which buttons to press on the equipment to produce the desired output,” write the researchers.

Students in traditional labs, therefore, don’t need to think about physics content but only how to correctly follow the instructions. But, write Holmes and Wieman, “overcoming obstacles and learning from failure are vital skills for every experimental scientist… Also important [is] having the time both to reflect on those decisions and their outcomes and to fix and improve the experiments iteratively.”

The innovative lab design that Holmes and Wieman offer as one alternative in their paper – structured quantitative inquiry labs (SQILabs) – emphasize iterative experimentation, decision-making and developing quantitative critical thinking skills. While SQILab activities give students a limited and realistic goal, the students decide how to conduct the experiment and interpret the data. They have the opportunity to troubleshoot, revise and test models, and try new things.

The researchers found that SQILab activities are more enjoyable for students and decrease their sense of frustration when things don’t go as planned. The students were also less likely to manipulate the data for a desired result.

“Rather than being seen by students as pointless and frustrating hoops that have to be jumped through, introductory physics labs can instead offer rewarding intellectual experiences,” conclude Holmes and Wieman.

http://mediarelations.cornell.edu/2018/01/02/research-reveals-shocking-weakness-of-lab-courses/