Chemist

From Wikipedia, the free encyclopedia

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

The Apothecary or The Chemist, a portrait by Gabriël Metsu, c. 1651–67

A chemist (from Greek chēm(ía) alchemy; replacing chymist from Medieval Latin alchemist) is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of matter and its properties. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms. Chemists carefully measure substance proportions, chemical reaction rates, and other chemical properties. In Commonwealth English, pharmacists are often called chemists.

Chemists use their knowledge to learn the composition and properties of unfamiliar substances, as well as to reproduce and synthesize large quantities of useful naturally occurring substances and create new artificial substances and useful processes. Chemists may specialize in any number of subdisciplines of chemistry. Materials scientists and metallurgists share much of the same education and skills with chemists. The work of chemists is often related to the work of chemical engineers, who are primarily concerned with the proper design, construction and evaluation of the most cost-effective large-scale chemical plants and work closely with industrial chemists on the development of new processes and methods for the commercial-scale manufacture of chemicals and related products.

History of chemistry

Main article: History of chemistry

German chemist Georgius Agricola (1494–1555) was the first to drop the Arabic definite article al-, exclusively writing chymia and chymista in describing activity that we today would characterize as chemical or alchemical.

Russian chemist Dmitri Mendeleev, author of the first modern periodic table of elements

Antoine Lavoisier (1743–94) is considered the "Father of Modern Chemistry".

The roots of chemistry can be traced to the phenomenon of burning. Fire was a mystical force that transformed one substance into another and thus was of primary interest to mankind. It was fire that led to the discovery of iron and glasses. After gold was discovered and became a precious metal, many people were interested to find a method that could convert other substances into gold. This led to the protoscience called alchemy. The word chemist is derived from the Neo-Latin noun chimista, an abbreviation of alchimista (alchemist). Alchemists discovered many chemical processes that led to the development of modern chemistry.

Chemistry as we know it today, was invented by Antoine Lavoisier with his law of conservation of mass in 1783. The discoveries of the chemical elements has a long history culminating in the creation of the periodic table by Dmitri Mendeleev. The Nobel Prize in Chemistry created in 1901 gives an excellent overview of chemical discovery since the start of the 20th century.

At the Washington Academy of Sciences during World War I, it was said that the side with the best chemists would win the war.

Education

Formal education

Jobs for chemists generally require at least a bachelor's degree in chemistry, which takes four years. However, many positions, especially those in research, require a Master of Science or a Doctor of Philosophy (PhD.). Most undergraduate programs emphasize mathematics and physics as well as chemistry, partly because chemistry is also known as "the central science", thus chemists ought to have a well-rounded knowledge about science. At the Master's level and higher, students tend to specialize in a particular field. Fields of specialization include biochemistry, nuclear chemistry, organic chemistry, inorganic chemistry, polymer chemistry, analytical chemistry, physical chemistry, theoretical chemistry, quantum chemistry, environmental chemistry, and thermochemistry. Postdoctoral experience may be required for certain positions.

Workers whose work involves chemistry, but not at a complexity requiring an education with a chemistry degree, are commonly referred to as chemical technicians. Such technicians commonly do such work as simpler, routine analyses for quality control or in clinical laboratories, having an associate degree. A chemical technologist has more education or experience than a chemical technician but less than a chemist, often having a bachelor's degree in a different field of science with also an associate degree in chemistry (or many credits related to chemistry) or having the same education as a chemical technician but more experience. There are also degrees specific to become a chemical technologist, which are somewhat distinct from those required when a student is interested in becoming a professional chemist. A Chemical technologist is more involved in the management and operation of the equipment and instrumentation necessary to perform chemical analyzes than a chemical technician. They are part of the team of a chemical laboratory in which the quality of the raw material, intermediate products and finished products is analyzed. They also perform functions in the areas of environmental quality control and the operational phase of a chemical plant.

Training

In addition to all the training usually given to chemical technologists in their respective degree (or one given via an associate degree), a chemist is also trained to understand more details related to chemical phenomena so that the chemist can be capable of more planning on the steps to achieve a distinct goal via a chemistry-related endeavor. The higher the competency level achieved in the field of chemistry (as assessed via a combination of education, experience and personal achievements), the higher the responsibility given to that chemist and the more complicated the task might be. Chemistry, as a field, has so many applications that different tasks and objectives can be given to workers or scientists with these different levels of education or experience. The specific title of each job varies from position to position, depending on factors such as the kind of industry, the routine level of the task, the current needs of a particular enterprise, the size of the enterprise or hiring firm, the philosophy and management principles of the hiring firm, the visibility of the competency and individual achievements of the one seeking employment, economic factors such as recession or economic depression, among other factors, so this makes it difficult to categorize the exact roles of these chemistry-related workers as standard for that given level of education. Because of these factors affecting exact job titles with distinct responsibilities, some chemists might begin doing technician tasks while other chemists might begin doing more complicated tasks than those of a technician, such as tasks that also involve formal applied research, management, or supervision included within the responsibilities of that same job title. The level of supervision given to that chemist also varies in a similar manner, with factors similar to those that affect the tasks demanded for a particular chemist.

A chemist in the lab of the Warsaw University of Technology in 2011

It is important that those interested in a Chemistry degree understand the variety of roles available to them (on average), which vary depending on education and job experience. Those Chemists who hold a bachelor's degree are most commonly involved in positions related to either research assistance (working under the guidance of senior chemists in a research-oriented activity), or, alternatively, they may work on distinct (chemistry-related) aspects of a business, organization or enterprise including aspects that involve quality control, quality assurance, manufacturing, production, formulation, inspection, method validation, visitation for troubleshooting of chemistry-related instruments, regulatory affairs, "on-demand" technical services, chemical analysis for non-research purposes (e.g., as a legal request, for testing purposes, or for government or non-profit agencies); chemists may also work in environmental evaluation and assessment. Other jobs or roles may include sales and marketing of chemical products and chemistry-related instruments or technical writing. The more experience obtained, the more independence and leadership or management roles these chemists may perform in those organizations. Some chemists with relatively higher experience might change jobs or job position to become a manager of a chemistry-related enterprise, a supervisor, an entrepreneur or a chemistry consultant. Other chemists choose to combine their education and experience as a chemist with a distinct credential to provide different services (e.g., forensic chemists, chemistry-related software development, patent law specialists, environmental law firm staff, scientific news reporting staff, engineering design staff, etc.).

In comparison, chemists who have obtained a Master of Science (M.S.) in chemistry or in a very related discipline may find chemist roles that allow them to enjoy more independence, leadership and responsibility earlier in their careers with less years of experience than those with a bachelor's degree as highest degree. Sometimes, M.S. chemists receive more complex tasks duties in comparison with the roles and positions found by chemists with a bachelor's degree as their highest academic degree and with the same or close-to-same years of job experience. There are positions that are open only to those that at least have a degree related to chemistry at the master's level. Although good chemists without a Ph.D. degree but with relatively many years of experience may be allowed some applied research positions, the general rule is that Ph.D. chemists are preferred for research positions and are typically the preferred choice for the highest administrative positions on big enterprises involved in chemistry-related duties. Some positions, especially research oriented, will only allow those chemists who are Ph.D. holders. Jobs that involve intensive research and actively seek to lead the discovery of completely new chemical compounds under specifically assigned monetary funds and resources or jobs that seek to develop new scientific theories require a Ph.D. more often than not. Chemists with a Ph.D. as the highest academic degree are found typically on the research-and-development department of an enterprise and can also hold university positions as professors. Professors for research universities or for big universities usually have a Ph.D., and some research-oriented institutions might require post-doctoral training. Some smaller colleges (including some smaller four-year colleges or smaller non-research universities for undergraduates) as well as community colleges usually hire chemists with a M.S. as professors too (and rarely, some big universities who need part-time or temporary instructors, or temporary staff), but when the positions are scarce and the applicants are many, they might prefer Ph.D. holders instead.

Skills

Skills that a chemist may need on the job include:

• Knowledge of chemistry
• Familiarity with product development
• Using scientific rules, strategies, or concepts to solve problems
• Putting together small parts using hands and fingers with dexterity

Employment

Analytical chemists testing samples of explosives at Royal Naval Cordite Factory, Holton Heath during World War II

Most chemists begin their lives in research laboratories. Many chemists continue working at universities. Other chemists may start companies, teach at high schools or colleges, take samples outside (as environmental chemists), or work in medical examiner offices or police departments (as forensic chemists).

Some software that chemists may find themselves using include:

• ChemSW Buffer Maker
• LabTrack Electronic Lab Notebook
• Agilent ChemStation
• Waters Empower Chromatography Data Software
• Microsoft Excel

Increasingly, chemists may also find themselves using artificial intelligence, such as for drug discovery.

Subdisciplines

Chemistry is typically organised into several major subdisciplines — including organic, inorganic, physical, analytical, and biochemistry — and encompasses numerous specialised and interdisciplinary fields. Many of these areas overlap with one another and with related sciences, and chemical research often intersects with disciplines such as biology, medicine, physics, materials science, and engineering.

• Analytical chemistry is the analysis of material samples to gain an understanding of their chemical composition and structure. Analytical chemistry incorporates standardized experimental methods in chemistry. These methods may be used in all subdisciplines of chemistry, excluding purely theoretical chemistry.
• Biochemistry is the study of the chemicals, chemical reactions and chemical interactions that take place in living organisms. Biochemistry and organic chemistry are closely related, for example, in medicinal chemistry.

A chemist prepares a new fuel cell for testing at Argonne National Laboratory, Lemont, Illinois.

A chemist pours from a round-bottom flask at Lawrence Livermore National Laboratory, Livermore, California.

• Inorganic chemistry is the study of the properties and reactions of inorganic compounds. The distinction between organic and inorganic disciplines is not absolute and there is much overlap, most importantly in the sub-discipline of organometallic chemistry. The Inorganic chemistry is also the study of atomic and molecular structure and bonding.
• Medicinal chemistry is the science involved with designing, synthesizing and developing pharmaceutical drugs. Medicinal chemistry involves the identification, synthesis and development of new chemical entities suitable for therapeutic use. It also includes the study of existing drugs, their biological properties, and their quantitative structure-activity relationships.
• Organic chemistry is the study of the structure, properties, composition, mechanisms, and chemical reaction of carbon compounds.
• Physical chemistry is the study of the physical fundamental basis of chemical systems and processes. In particular, the energetics and dynamics of such systems and processes are of interest to physical chemists. Important areas of study include chemical thermodynamics, chemical kinetics, electrochemistry, quantum chemistry, statistical mechanics, and spectroscopy. Physical chemistry has a large overlap with theoretical chemistry and molecular physics. Physical chemistry involves the use of calculus in deriving equations.
• Theoretical chemistry is the study of chemistry via theoretical reasoning (usually within mathematics or physics). In particular, the application of quantum mechanics to chemistry is called quantum chemistry. Since the end of the Second World War, the development of computers has allowed a systematic development of computational chemistry, which is the art of developing and applying computer programs for solving chemical problems. Theoretical chemistry has large overlap with condensed matter physics and molecular physics. See reductionism.

All the above major areas of chemistry employ chemists. Other fields where chemical degrees are useful include astrochemistry (and cosmochemistry), atmospheric chemistry, chemical engineering, chemo-informatics, electrochemistry, environmental science, forensic science, geochemistry, green chemistry, history of chemistry, materials science, medical science, molecular biology, molecular genetics, nanotechnology, nuclear chemistry, oenology, organometallic chemistry, petrochemistry, pharmacology, photochemistry, phytochemistry, polymer chemistry, supramolecular chemistry and surface chemistry.

Professional societies

Chemists may belong to professional societies specifically for professionals and researchers within the field of chemistry, such as the Royal Society of Chemistry in the United Kingdom, the American Chemical Society (ACS) in the United States, or the Institution of Chemists in India.

Ethics

The "Global Chemists' Code of Ethics" suggests several ethical principles that all chemists should follow:

• Promoting the general public's appreciation of chemistry
• The importance of sustainability and protecting the environment
• The importance of scientific research and publications
• Respecting safety, such as by using proper personal protective equipment
• Respecting chemical security throughout the chemical supply chain, especially for labs and industrial facilities

This code of ethics was codified in a 2016 conference held in Kuala Lumpur, Malaysia, run by the American Chemical Society. The points listed are inspired by the 2015 Hague Ethical Guidelines.

Pathological science

From Wikipedia, the free encyclopedia

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

Pathological science is an area of research where "people are tricked into false results ... by subjective effects, wishful thinking or threshold interactions." The term was coined by Irving Langmuir, Nobel Prize-winning chemist, during a 1953 colloquium at the Knolls Research Laboratory. Langmuir said a pathological science is an area of research that simply will not "go away"—long after it was given up on as "false" by the majority of scientists in the field. He called pathological science "the science of things that aren't so."

In his 2002 book, Undead Science, sociology and anthropology Professor Bart Simon lists it among practices that are falsely perceived or presented to be science, "categories ... such as ... pseudoscience, amateur science, deviant or fraudulent science, bad science, junk science, pathological science, cargo cult science, and voodoo science." Examples of pathological science include the Martian canals, N-rays, and cold fusion. The theories and conclusions behind all of these examples are currently rejected or disregarded by the majority of scientists.

Definition

Irving Langmuir coined the term pathological science in a talk in 1953.

Pathological science, as defined by Langmuir, is a psychological process in which a scientist, originally conforming to the scientific method, unconsciously veers from that method, and begins a pathological process of wishful data interpretation (see the observer-expectancy effect and cognitive bias). Some characteristics of pathological science are:

• The maximum effect that is observed is produced by a causative agent of barely detectable intensity, and the magnitude of the effect is substantially independent of the intensity of the cause.
• The effect is of a magnitude that remains close to the limit of detectability, or multiple measurements are necessary because of the low statistical significance of the results.
• There are claims of great accuracy.
• Fantastic theories contrary to experience are suggested.
• Criticisms are met by ad hoc excuses.
• The ratio of supporters to critics rises and then falls gradually to oblivion.

Langmuir never intended the term to be rigorously defined; it was simply the title of his talk on some examples of "weird science". As with any attempt to define the scientific endeavor, examples and counterexamples can always be found.

Langmuir's examples

Fig. 6,7 from Prosper-René Blondlot: "Registration by Photography of the Action Produced by N Rays on a Small Electric Spark". Nancy, 1904.

N-rays

Main article: N ray

Langmuir's discussion of N-rays has led to their traditional characterization as an instance of pathological science.

In 1903, Prosper-René Blondlot was working on X-rays (as were other physicists of the era) and noticed a new visible radiation that could penetrate aluminium. He devised experiments in which a barely visible object was illuminated by these N-rays, and thus became "more visible". Blondlot claimed that N-rays were causing a small visual reaction, too small to be seen under normal illumination, but just visible when most normal light sources were removed and the target was just barely visible to begin with.

N-rays became the topic of some debate within the science community. After a time, American physicist Robert W. Wood decided to visit Blondlot's lab, which had moved on to the physical characterization of N-rays. An experiment passed the rays from a 2 mm slit through an aluminium prism, from which he was measuring the index of refraction to a precision that required measurements accurate to within 0.01 mm. Wood asked how it was possible that he could measure something to 0.01 mm from a 2 mm source, a physical impossibility in the propagation of any kind of wave. Blondlot replied, "That's one of the fascinating things about the N-rays. They don't follow the ordinary laws of science that you ordinarily think of." Wood then asked to see the experiments being run as usual, which took place in a room required to be very dark so the target was barely visible. Blondlot repeated his most recent experiments and got the same results—despite the fact that Wood had reached over and covertly sabotaged the N-ray apparatus by removing the prism.

Other examples

Langmuir offered additional examples of what he regarded as pathological science in his original speech:

• The Davis–Barnes effect (1929; after Professor Bergen Davis from Columbia University)
• Mitogenetic rays (1923; Alexander Gurwitsch and others)
• The Allison effect (1927; after Fred Allison)
• Extrasensory perception (1934), where Rhine consciously discarded contrary test results because he felt they could not be correct.

Later examples

A 1985 version of Langmuir's speech offered more examples, although at least one of these (polywater) occurred entirely after Langmuir's death in 1957:

• Water dowsing
• Martian canals (observed in late 19th century and early 20th century, they turned out to be optical illusions.)
• Certain reported photomechanical and electromechanical effects
• Biological effects of magnetic fields (see magnetobiology and magnet therapy) except magnetoception

Newer examples

Since Langmuir's original talk, a number of newer examples of what appear to be pathological science have appeared. Denis Rousseau has cited as examples the cases of Martin Fleischmann's cold fusion and Jacques Benveniste's "infinite dilution".

Cold fusion

Main article: Cold fusion

In 1989, Martin Fleischmann and Stanley Pons announced the discovery of a simple and cheap procedure to obtain room-temperature nuclear fusion. Although there were multiple instances where successful results were reported, they lacked consistency and hence cold fusion came to be considered to be an example of pathological science. Two panels convened by the US Department of Energy, one in 1989 and a second in 2004, did not recommend a dedicated federal program for cold fusion research. A small number of researchers continue working in the field.

Water memory

Main articles: Benveniste affair and Water memory

Jacques Benveniste was a French immunologist who in 1988 published a paper in the prestigious scientific journal Nature describing the action of high dilutions of anti-IgE antibody on the degranulation of human basophils, findings which seemed to support the concept of homeopathy. Biologists were puzzled by Benveniste's results, as only molecules of water, and no molecules of the original antibody, remained in these high dilutions. Benveniste concluded that the configuration of molecules in water was biologically active. Subsequent investigations have not supported Benveniste's findings.

Scientific literacy

From Wikipedia, the free encyclopedia

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

Scientific literacy or science literacy encompasses written, numerical, and digital literacy as they pertain to understanding science, its methodology, observations, and theories. Scientific literacy is chiefly concerned with an understanding of the scientific method, units and methods of measurement, empiricism and understanding of statistics in particular correlations and qualitative versus quantitative observations and aggregate statistics. It is also concerned with a basic understanding of core scientific fields, such as physics, chemistry, biology, ecology, geology and computation.

Definition

The Organisation for Economic Co-operation and Development (OECD) Programme for International Student Assessment (PISA) Framework (2015) defines scientific literacy as "the ability to engage with science-related issues, and with the ideas of science, as a reflective citizen." A scientifically literate person, therefore, is willing to engage in reasoned discourse about science and technology which requires the competencies to:

• Explain phenomena scientifically – recognize, offer and evaluate explanations for a range of natural and technological phenomena.
• Evaluate and design scientific inquiry – describe and appraise scientific investigations and propose ways of addressing questions scientifically.
• Interpret data and evidence scientifically – analyze and evaluate data, claims and arguments in a variety of representations and draw appropriate scientific conclusions.

According to the United States National Center for Education Statistics, "scientific literacy is the knowledge and understanding of scientific concepts and processes required for personal decision making, participation in civic and cultural affairs, and economic productivity". A scientifically literate person is defined as one who has the capacity to:

• Understand, experiment, and reason as well as interpret scientific facts and their meaning.
• Ask, find, or determine answers to questions derived from curiosity about everyday experiences.
• Describe, explain, and predict natural phenomena.
• Read articles with understanding of science in the popular press and engage in social conversation about the validity of the conclusions.
• Identify scientific issues underlying national and local decisions and express positions that are scientifically and technologically informed.
• Evaluate the quality of scientific information on the basis of its source and the methods used to generate it.
• Pose and evaluate arguments based on evidence and to apply conclusions from such arguments appropriately.

Scientific literacy may also be defined in language similar to the definitions of ocean literacy, Earth science literacy and climate literacy. Thus a scientifically literate person can:

• Understand the science relevant to environmental and social issues.
• Communicate clearly about the science.
• Make informed decisions about these issues.

Finally, scientific literacy may involve particular attitudes toward learning and using science. Scientifically-literate citizens are capable of researching matters of fact for themselves. Reforms in science education in the United States have often been driven by strategic challenges such as the launch of the Sputnik satellite in 1957 and the Japanese economic boom in the 1980s. The phrase science literacy was popularized by Paul Hurd in 1958, when he charged that the immediate problem in education was "one of closing the gap between the wealth of scientific achievement and the poverty of scientific literacy in America". For Hurd, rapid innovation in science and technology demanded an education "appropriate for meeting the challenges of an emerging scientific revolution." Underlying Hurd's call was the idea "that some mastery of science is essential preparation for modern life."

Initial definitions of science literacy included elaborations of the content that people should understand, often following somewhat traditional lines (biology, chemistry, physics). Earth science was somewhat narrowly defined as expanded geological processes. In the decade after those initial documents, ocean scientists and educators revised the notion of science literacy to include more contemporary, systems-oriented views of the natural world, leading to scientific literacy programs for the ocean, climate, earth science, and so on.

Since the 1950s, scientific literacy has increasingly emphasized scientific knowledge being as socially situated and heavily influenced by personal experience. Science literacy is seen as a human right and a working knowledge of science and its role in society is seen as a requirement for responsible members of society, one that helps average people to make better decisions and enrich their lives. In the United States, this change in emphasis can be noted in the late 1980s and early 1990s, with the publication of Science for All Americans and Benchmarks for Science Literacy.

The National Science Education Standards (1996) defined scientific literacy as "the knowledge and understanding of scientific concepts and processes required for personal decision making, participation in civic and cultural affairs, and economic productivity". In addition, it emphasized that scientific literacy was not simply a matter of remembering specific scientific content. It involved the development of key abilities or skills. "Scientific literacy means that a person can ask, find, or determine answers to questions derived from curiosity about everyday experiences. It means that a person has the ability to describe, explain, and predict natural phenomena."

Some emphasize the importance of an underlying "ethos" that makes it possible to participate in scientific debates and communities. Key norms are that the observations and hypotheses of scientific discovery are part of a communally shared process; that ideas are important, not the status of the person who voices them; that what matters is disinterested evidence, not desired outcomes; and that statements that go beyond observations should be subject to testing.

More recently, calls for "scientific literacy" have identified misinformation and disinformation as dangers. They suggest that civic science literacy, digital media science literacy, and cognitive science literacy are all important components of education, if individuals are to be scientifically informed and engage in individual and collective decision-making in a democratic society.

Comparisons of the views of citizens and scientists by the Pew Research Center suggest that they hold very different positions on a range of science, engineering and technology-related issues. Both citizens and scientists rate K–12 STEM education in the U.S. poorly.

Science, society, and the environment

The interdependence of humans and our natural environment is at the heart of scientific literacy in the Earth systems. As defined by nationwide consensus among scientists and educators, this literacy has two key parts. First, a literate person is defined, in language that echoes the above definition of scientific literacy. Second, a set of concepts are listed, organized into six to nine big ideas or essential principles. This defining process was undertaken first for ocean literacy, then for the Great Lakes, estuaries, the atmosphere, and climate. Earth science literacy is one of the types of literacy defined for Earth systems; the qualities of an Earth science literate person are representative of the qualities for all the Earth system literacy definitions.

According to the Earth Science Literacy Initiative, an Earth-science-literate person:

• understands the fundamental concepts of Earth's many systems
• knows how to find and assess scientifically credible information about Earth
• communicates about Earth science in a meaningful way
• is able to make informed and responsible decisions regarding Earth and its resources

All types of literacy in Earth systems have a definition like the above. Ocean literacy is further defined as "understanding our impact on the ocean and the ocean's impact on us". Similarly, the climate literacy website includes a guiding principle for decision making; "humans can take action to reduce climate change and its impacts". Each type of Earth systems literacy then defines the concepts students should understand upon graduation from high school. Current educational efforts in Earth systems literacy tend to focus more on the scientific concepts than on the decision-making aspect of literacy, but environmental action remains as a stated goal.

The theme of science in a socially-relevant context appears in many discussions of scientific literacy. Ideas that turn up in the life sciences include an allusion to ecological literacy, the "well-being of earth". Robin Wright, a writer for Cell Biology Education, laments "will [undergraduates'] misunderstandings or lack of knowledge about science imperil our democratic way of life and national security?" A discussion of physics literacy includes energy conservation, ozone depletion and global warming. The mission statement of the Chemistry Literacy Project includes environmental and social justice. Technological literacy is defined in a three-dimensional coordinate space; on the knowledge axis, it is noted that technology can be risky, and that it "reflects the values and culture of society". Energy literacy boasts several websites, including one associated with climate literacy.

Attitudes about science

Attitudes about science can have a significant effect on scientific literacy. In education theory, understanding of content lies in the cognitive domain, while attitudes lie in the affective domain. Thus, negative attitudes, such as fear of science, can act as an affective filter and an impediment to comprehension and future learning goals. In the United States, student attitudes toward science are known to decline beginning in fourth grade and continue to decline through middle and high school. This beginning of negative feelings about science stems from a greater emphasis put on grades. Students begin to feel that they are achieving less which causes them to lose motivation in the classroom and student participation drops. It has been well documented that students who retain high motivation for learning will have a more positive attitude toward the subject. Studies of college students' attitudes about learning physics suggest that these attitudes may be divided into categories of real world connections, personal connections, conceptual connections, student effort and problem-solving.

The decision-making aspect of science literacy suggests further attitudes about the state of the world, one's responsibility for its well-being and one's sense of empowerment to make a difference. These attitudes may be important measures of science literacy, as described in the case of ocean literacy.

In the K–12 classroom, learning standards do not commonly address the affective domain due to the difficulty in developing teaching strategies and in assessing student attitude. Many modern teaching strategies have been shown to have positive impacts on student attitudes toward science including the use of student-centered instruction, innovative learning strategies and utilizing a variety of teaching techniques. Project-based learning has also been shown to improve student attitudes about a subject and improve their scientific processing skills.

Teachers can use Likert scales or differential scales to determine and monitor changes in student attitudes towards science and science learning.

Promoting and measuring

Proponents of scientific literacy tend to focus on what is learned by the time a student graduates from high school. Science literacy has always been an important element of the standards movement in education. All science literacy documents have been drafted with the explicit intent of influencing educational standards, as a means to drive curriculum, teaching, assessment, and ultimately, learning nationwide. Moreover, scientific literacy provides an important basis for making informed social decisions. Science is a human process carried out in a social context, which makes it relevant as a part of our science education. In order for people to make evidence-informed decision, everyone should seek to improve their scientific literacy.

Relevant research has suggested ways to promote scientific literacy to students more efficiently. Programs to promote scientific literacy among students abound, including several programs sponsored by technology companies, as well as quiz bowls and science fairs. A partial list of such programs includes the Global Challenge Award, the National Ocean Sciences Bowl and Action Bioscience.

Some organizations have attempted to compare the scientific literacy of adults in different countries. The OECD found that scientific literacy in the United States is not measurably different from the OECD average. Science News reports "The new U.S. rate, based on questionnaires administered in 2008, is seven percentage points behind Sweden, the only European nation to exceed the Americans. The U.S. figure is slightly higher than that for Denmark, Finland, Norway and the Netherlands. And it's double the 2005 rate in the United Kingdom (and the collective rate for the European Union)."

University educators are attempting to develop reliable instruments to measure scientific literacy, and the use of concept inventories is increasing in the fields of physics, astronomy, chemistry, biology and earth science.

3D modeling

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/3D_modeling

 

Three-dimensional (3D) computer graphics

In 3D computer graphics, 3D modeling is the process of developing a mathematical coordinate-based representation of a surface of an object (inanimate or living) in three dimensions via specialized software by manipulating edges, vertices, and polygons in a simulated 3D space.

Three-dimensional (3D) models represent a physical body using a collection of points in 3D space, connected by various geometric entities such as triangles, lines, curved surfaces, etc. Being a collection of data (points and other information), 3D models can be created manually, algorithmically (procedural modeling), or by scanning. Their surfaces may be further defined with texture mapping.

Outline

See also: Environment artist

The product is called a 3D model, while someone who works with 3D models may be referred to as a 3D artist or a 3D modeler.

A 3D model can also be displayed as a two-dimensional image through a process called 3D rendering or used in a computer simulation of physical phenomena.

3D models may be created automatically or manually. The manual modeling process of preparing geometric data for 3D computer graphics is similar to plastic arts such as sculpting. The 3D model can be physically created using 3D printing devices that form 2D layers of the model with three-dimensional material, one layer at a time. Without a 3D model, a 3D print is not possible.

3D modeling software is a class of 3D computer graphics software used to produce 3D models. Individual programs of this class are called modeling applications.

History

Three-dimensional model of a spectrograph

Rotating 3D video-game model

3D selfie models are generated from 2D pictures taken at the Fantasitron 3D photo booth at Madurodam.

3D models are now widely used anywhere in 3D graphics and CAD but their history predates the widespread use of 3D graphics on personal computers.

In the past, many computer games used pre-rendered images of 3D models as sprites before computers could render them in real-time. The designer can then see the model in various directions and views, this can help the designer see if the object is created as intended to compared to their original vision. Seeing the design this way can help the designer or company figure out changes or improvements needed to the product. Simple wireframes were the first versions of early 3D models, which were mainly used to view construction plans and mechanical parts. Better graphics hardware and software allowed for the creation of solid and surface models in the 1970s and 1980s, giving designers a more realistic and clear representation of physical objects. By the 1990s, parametric modeling became popular, letting designers change a model by changing its basic parameters instead of redrawing it from scratch. Thanks to virtual reality, artificial intelligence and generative design tools, 3D modeling today goes past engineering and is influencing fields like animation, gaming, product design and cinema.

Representation

A modern render of the iconic Utah teapot model developed by Martin Newell (1975). The Utah teapot is one of the most common models used in 3D graphics education.

Almost all 3D models can be divided into two categories:

• Solid – These models define the volume of the object they represent (like a rock). Solid models are mostly used for engineering and medical simulations, and are usually built with constructive solid geometry.
• Shell or boundary – These models represent the surface, i.e., the boundary of the object, not its volume (like an infinitesimally thin eggshell). Almost all visual models used in games and film are shell models.

Solid and shell modeling can create functionally identical objects. Differences between them are mostly variations in the way they are created and edited and conventions of use in various fields and differences in types of approximations between the model and reality.

Shell models must be manifold (having no holes or cracks in the shell) to be meaningful as a real object. For example, in a shell model of a cube, all six sides must be connected with no gaps in the edges or the corners. Polygonal meshes (and to a lesser extent, subdivision surfaces) are by far the most common representation. Level sets are a useful representation for deforming surfaces that undergo many topological changes, such as fluids.

The process of transforming representations of objects, such as the middle point coordinate of a sphere and a point on its circumference, into a polygon representation of a sphere is called tessellation. This step is used in polygon-based rendering, where objects are broken down from abstract representations ("primitives") such as spheres, cones etc., to so-called meshes, which are nets of interconnected triangles. Meshes of triangles (instead of e.g., squares) are popular as they have proven to be easy to rasterize (the surface described by each triangle is planar, so the projection is always convex). Polygon representations are not used in all rendering techniques, and in these cases the tessellation step is not included in the transition from abstract representation to rendered scene.

Process

There are four popular ways to represent a model:

• Parametric modeling – A feature-based parametric modeling structure, which relies on parent-child relationships between features, allowing for a number of methods for building specific models in the context of mechanical CAD systems.

• Polygonal modeling – Points in 3D space, called vertices, are connected by line segments to form a polygon mesh. The vast majority of 3D models today are built as textured polygonal models because they are flexible and because computers can render them so quickly. However, polygons are planar and can only approximate curved surfaces using many polygons.
• Curve modeling – Surfaces are defined by curves, which are influenced by weighted control points. The curve follows (but does not necessarily interpolate) the points. Increasing the weight for a point pulls the curve closer to that point. Curve types include nonuniform rational B-spline (NURBS), splines, patches, and geometric primitives.
• Digital sculpting – There are three types of digital sculpting: Displacement, which is the most widely used among applications at this moment, uses a dense model (often generated by subdivision surfaces of a polygon control mesh) and stores new locations for the vertex positions through use of an image map that stores the adjusted locations. Volumetric, loosely based on voxels, has similar capabilities as displacement but does not suffer from polygon stretching when there are not enough polygons in a region to achieve a deformation. Dynamic tessellation, which is similar to voxel, divides the surface using triangulation to maintain a smooth surface and allow finer details. These methods allow for artistic exploration as the model has new topology created over it once the models form and possibly details have been sculpted. The new mesh usually has the original high-resolution mesh information transferred into displacement data or normal map data if it is for a game engine.

A 3D fantasy fish composed of organic surfaces generated using LAI4D

The modeling stage consists of shaping individual objects that are later used in the scene. There are a number of modeling techniques, including:

• Constructive solid geometry
• Implicit surfaces
• Subdivision surfaces

Modeling can be performed by means of a dedicated program (e.g., 3D modeling software like Adobe Substance, Blender, Cinema 4D, LightWave, Maya, Modo, 3ds Max, SketchUp, Rhinoceros 3D, and others) or an application component (Shaper, Lofter in 3ds Max) or some scene description language (as in POV-Ray). In some cases, there is no strict distinction between these phases; in such cases, modeling is just part of the scene creation process (this is the case, for example, with Caligari trueSpace and Realsoft 3D).

3D models can also be created using the technique of Photogrammetry with dedicated programs such as RealityCapture, Metashape and 3DF Zephyr. Cleanup and further processing can be performed with applications such as MeshLab, the GigaMesh Software Framework, netfabb or MeshMixer. Photogrammetry creates models using algorithms to interpret the shape and texture of real-world objects and environments based on photographs taken from many angles of the subject.

Complex materials such as blowing sand, clouds, and liquid sprays are modeled with particle systems, and are a mass of 3D coordinates which have either points, polygons, texture splats or sprites assigned to them.

3D modeling software

Main article: List of 3D modeling software

There are a variety of 3D modeling programs that can be used in the industries of engineering, interior design, film and others. Each 3D modeling software has specific capabilities and can be utilized to fulfill demands for the industry.

G-code

Many programs include export options to form a g-code, applicable to additive or subtractive manufacturing machinery. G-code (computer numerical control) works with automated technology to form a real-world rendition of 3D models. This code is a specific set of instructions to carry out steps of a product's manufacturing.

Human models

Main article: Virtual actor

The first widely available commercial application of human virtual models appeared in 1998 on the Lands' End web site. The human virtual models were created by the company My Virtual Mode Inc. and enabled users to create a model of themselves and try on 3D clothing. There are several modern programs that allow for the creation of virtual human models (Poser being one example).

3D clothing

Dynamic 3D clothing model made in Marvelous Designer

The development of cloth simulation software such as Marvelous Designer, CLO3D and Optitex, has enabled artists and fashion designers to model dynamic 3D clothing on the computer. Dynamic 3D clothing is used for virtual fashion catalogs, as well as for dressing 3D characters for video games, 3D animation movies, for digital doubles in movies, as a creation tool for digital fashion brands, as well as for making clothes for avatars in virtual worlds such as SecondLife.

Comparison with 2D methods

3D photorealistic effects are often achieved without wire-frame modeling and are sometimes indistinguishable in the final form. Some graphic art software includes filters that can be applied to 2D vector graphics or 2D raster graphics on transparent layers.

Advantages of wireframe 3D modeling over exclusively 2D methods include:

• Flexibility, ability to change angles or animate images with quicker rendering of the changes;
• Ease of rendering, automatic calculation and rendering photorealistic effects rather than mentally visualizing or estimating;
• Accurate photorealism, less chance of human error in misplacing, overdoing, or forgetting to include a visual effect.

Disadvantages compared to 2D photorealistic rendering may include a software learning curve and difficulty achieving certain photorealistic effects. Some photorealistic effects may be achieved with special rendering filters included in the 3D modeling software. For the best of both worlds, some artists use a combination of 3D modeling followed by editing the 2D computer-rendered images from the 3D model.

3D model market

A large market for 3D models (as well as 3D-related content, such as textures, scripts, etc.) exists—either for individual models or large collections. Several online marketplaces for 3D content allow individual artists to sell content that they have created, including TurboSquid, MyMiniFactory, Sketchfab, CGTrader, and Cults. Often, the artists' goal is to get additional value out of assets they have previously created for projects. By doing so, artists can earn more money out of their old content, and companies can save money by buying pre-made models instead of paying an employee to create one from scratch. These marketplaces typically split the sale between themselves and the artist that created the asset, artists get 40% to 95% of the sales according to the marketplace. In most cases, the artist retains ownership of the 3d model while the customer only buys the right to use and present the model. Some artists sell their products directly in their own stores, offering their products at a lower price by not using intermediaries.

The architecture, engineering and construction (AEC) industry is the biggest market for 3D modeling, with an estimated value of $12.13 billion by 2028. This is due to the increasing adoption of 3D modeling in the AEC industry, which helps to improve design accuracy, reduce errors and omissions and facilitate collaboration among project stakeholders.

Over the last several years numerous marketplaces specializing in 3D rendering and printing models have emerged. Some of the 3D printing marketplaces are a combination of models sharing sites, with or without a built in e-com capability. Some of those platforms also offer 3D printing services on demand, software for model rendering and dynamic viewing of items.

3D printing

Main articles: 3D printing and Rapid prototyping

The term 3D printing or three-dimensional printing is a form of additive manufacturing technology where a three-dimensional object is created from successive layers of material. Objects can be created without the need for complex and expensive molds or assembly of multiple parts. 3D printing allows ideas to be prototyped and tested without having to go through a more time-consuming production process.

3D models can be purchased from online markets and printed by individuals or companies using commercially available 3D printers, enabling the home-production of objects such as spare parts and even medical equipment.

Uses

Steps of forensic facial reconstruction of a mummy made in Blender by the Brazilian 3D designer Cícero Moraes

3D modeling is used in many industries.

• The medical industry uses detailed models of organs created from multiple two-dimensional image slices from an MRI or CT scan. Other scientific fields can use 3D models to visualize and communicate information such as models of chemical compounds. It is also utilized to create patient specific models. These models are used for pre-operative planning, implant design and surgical guides. It is often used in tandem with 3d printing to produce anatomical models and cutting templates.
• The movie industry uses 3D models for computer-generated characters and objects in animated and real-life motion pictures. Similarly, the video game industry uses 3D models as assets for computer and video games. The source of the geometry for the shape of an object can be a designer, industrial engineer, or artist using a 3D CAD system; an existing object that has been reverse engineered or copied using a 3D shape digitizer or scanner; or mathematical data based on a numerical description or calculation of the object.
• The architecture industry uses 3D models to demonstrate proposed buildings and landscapes in lieu of traditional, physical architectural models. Additionally, the use of Level of Detail (LOD) in 3D models is becoming increasingly important in architecture, engineering and construction (AEC). 3D modeling is also utilized in massing, BIM workflows, clash detection, and visualization. This can provide an idea about the design intent to the stakeholders and connects to downstream fabrication via CNC and additive manufacturing.
• Archeologists create 3D models of cultural heritage items for research and visualization. For example, the International Institute of MetaNumismatics (INIMEN) studies the applications of 3D modeling for the digitization and preservation of numismatic artifacts. Moreover, photogrammetry and laser scanning support documentation of objects. It is used to conserve heritage and provide access to the public. Virtual reconstruction of items allows fragile artifacts to be studied without the risk of physically damaging them and to exhibit them on interactive sites or museums.
• In recent decades, the earth science community has started to construct 3D geological models as a standard practice. Analysis of groundwater, hazards and land-use change can be identified through using 3D terrain and subsurface models to integrate remote sensing and field data. 3D modelling tools create these models for planning and educational purposes.
• 3D models are also used in constructing digital representations of mechanical parts before they are manufactured. Using CAD- and CAM-related software, an engineer can test the functionality of assemblies of parts then use the same data to create toolpaths for CNC machining or 3D printing. It allows digital prototyping and simulation into product lines which improves the efficiency and reduces the waste of the process. It introduces tighter integration with digital twins and model based definition (MBD) as well as additive workflows.
• 3D modeling is used in industrial design, wherein products are 3D modeled before representing them to the clients.
• In media and event industries, 3D modeling is used in stage and set design.
• In education, student’s conceptual understanding has seen an improvement with the introduction of 3D models and animations especially in STEM classrooms. Structured exposure to the 3D modelling field can also foster creativity and spatial reasoning.
• In fashion and apparel, designers can test fit garments through body scanning and simulation to even check the drape and motion. This reduces waste and accelerates iterations and prototyping.

Due to the fact that software ecosystems vary across domains, it is common to differentiate between digital content  creation (DCC) tools (which consist of polygonal/ subdivision modelling, sculpting and rigging), CAD, CAM ( it is the parametric and solid modeling for mechanical design and manufacturing), BIM (which is building information modelling for AEC), and domain specific platforms (for example medical or geospatial). Open-source tools (for instance Blender, FreeCAD, MeshLab, OpenSCAD) coexist with commercial packages (some examples are: Autodesk Maya/3ds Max/Fusion 360, SolidWorks, CATIA, Cinema 4D, ZBrush, Rhino, Houdini, SketchUp, CLO 3D/Marvelous Designer, Revit, Archicad).

The OWL 2 translation of the vocabulary of X3D can be used to provide semantic descriptions for 3D models, which is suitable for indexing and retrieval of 3D models by features such as geometry, dimensions, material, texture, diffuse reflection, transmission spectra, transparency, reflectivity, opalescence, glazes, varnishes and enamels (as opposed to unstructured textual descriptions or 2.5D virtual museums and exhibitions using Google Street View on Google Arts & Culture, for example). The RDF representation of 3D models can be used in reasoning, which enables intelligent 3D applications which, for example, can automatically compare two 3D models by volume.

Overall, these examples are an illustration of 3D modelling being a tool of general purpose representational layer that creates a bridge between sensing to analysis, design, communication and fabrication.

Challenges and limitations

Despite 3D modelling being widely adopted in various domains, several constraints shape how the technology is utilized. Access and cost remain an issue in many regions of the world. Commercial licences, training, and capable hardware can be difficult to find in select regions. It can also be out of reach for students and small studios that can not afford it. Open-source ecosystems and school programs can aid in making this less of an issue, but availability and support are uneven which in turn creates an equity gap in who can learn and apply 3D modelling.

Workflow complexity is another limitation. To practice 3D modelling effectively it requires knowledge of many different things. A 3D modelling specialist needs to understand topology, UV mapping, rigging, simulation and rendering for DCC. For CAD/CAM modelling parametric constraints, tolerances and manufacturing constraints must be known by the developer. Information schema and coordination are both required for BIM. Moving assets between tools can introduce incompatibility issues (meshes vs. NURBS/solids/parametric features; unit scaling; normals; material definitions), and format conversions may cause data loss without careful management.

At scale, energy consumption can be large (this is due to high resolution simulations and rendering and dense 3D scans), which directs teams to try and optimize design complexity and adopting more efficient pipelines. In research and heritage work, there is another constraint where ethical and policy questions include provenance, licensing and representation (how “authoritative” a reconstruction should be labelled), especially as these reconstruction are utilized for public communication and educational purposes.

Finally, classroom and outreach deployments must take into account pedagogical support: learners need step by step guidance and clear examples and models to follow. Without this, the tool’s complexity will be more of a barrier that slows students down instead of enabling them to understand and be creative.

Sustainability via 3D modeling

• Minimizing the need for real prototypes – Designers can do early-stage usability testing without creating a physical prototype by using 3D CAD models as virtual replicas, which reduces waste and material consumption.
• Early discovery of design flaws – Testing with virtual models can help designers see ergonomic or usability problems early on and can lower the chance of making defective items. By doing this, waste from discarded physical prototypes is reduced.
• Quick iteration with minimal environmental effect – Digital modifications to CAD models are almost instantaneous when compared to retooling or rebuilding physical prototypes. This speeds up the design cycle without requiring more materials.

Simulations

In 3D modeling, simulations are digital processes that copy how things behave in the real world, in a virtual space. Without creating actual prototypes, it lets designers and animators test how objects move, interact, or react to forces. By recreating processes such as collisions, fluid movement, fabric draping, or particle motion, simulations help increase design accuracy, enhance visual effects, and save both time and materials.