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142-431: The organisation and contents of laboratories are determined by the differing requirements of the specialists working within. A physics laboratory might contain a particle accelerator or vacuum chamber , while a metallurgy laboratory could have apparatus for casting or refining metals or for testing their strength . A chemist or biologist might use a wet laboratory , while a psychologist's laboratory might be

284-499: A Platonist by Stephen Hawking , a view Penrose discusses in his book, The Road to Reality . Hawking referred to himself as an "unashamed reductionist" and took issue with Penrose's views. Mathematics provides a compact and exact language used to describe the order in nature. This was noted and advocated by Pythagoras , Plato , Galileo, and Newton. Some theorists, like Hilary Putnam and Penelope Maddy , hold that logical truths, and therefore mathematical reasoning, depend on

426-488: A frame of reference that is in motion with respect to an observer; the special theory of relativity is concerned with motion in the absence of gravitational fields and the general theory of relativity with motion and its connection with gravitation . Both quantum theory and the theory of relativity find applications in many areas of modern physics. While physics itself aims to discover universal laws, its theories lie in explicit domains of applicability. Loosely speaking,

568-415: A "what-if" question, without a specific expectation about what the experiment reveals, or to confirm prior results. If an experiment is carefully conducted, the results usually either support or disprove the hypothesis. According to some philosophies of science , an experiment can never "prove" a hypothesis, it can only add support. On the other hand, an experiment that provides a counterexample can disprove

710-457: A 'true experiment' is a method of social research in which there are two kinds of variables . The independent variable is manipulated by the experimenter, and the dependent variable is measured. The signifying characteristic of a true experiment is that it randomly allocates the subjects to neutralize experimenter bias , and ensures, over a large number of iterations of the experiment, that it controls for all confounding factors. Depending on

852-455: A basic awareness of the motions of the Sun, Moon, and stars. The stars and planets, believed to represent gods, were often worshipped. While the explanations for the observed positions of the stars were often unscientific and lacking in evidence, these early observations laid the foundation for later astronomy, as the stars were found to traverse great circles across the sky, which could not explain

994-410: A disease), and informed consent . For example, in psychology or health care, it is unethical to provide a substandard treatment to patients. Therefore, ethical review boards are supposed to stop clinical trials and other experiments unless a new treatment is believed to offer benefits as good as current best practice. It is also generally unethical (and often illegal) to conduct randomized experiments on

1136-420: A hard-to-find physical meaning. The final mathematical solution has an easier-to-find meaning, because it is what the solver is looking for. Physics is a branch of fundamental science (also called basic science). Physics is also called " the fundamental science" because all branches of natural science including chemistry, astronomy, geology, and biology are constrained by laws of physics. Similarly, chemistry

1278-423: A lab is contaminated, but often ends up in the contaminated waste, driving up energy costs for waste disposal. A good sorting and recycling system for non contaminated lab waste will allow lab users to act sustainably and correctly dispose of waste. As of 2021, there are numerous laboratories currently dedicating time and resources to move towards more sustainable lab practices at their facilities, e.g.  MIT and

1420-410: A logical/ mental derivation. In this process of critical consideration, the man himself should not forget that he tends to subjective opinions—through "prejudices" and "leniency"—and thus has to be critical about his own way of building hypotheses. Francis Bacon (1561–1626), an English philosopher and scientist active in the 17th century, became an influential supporter of experimental science in

1562-436: A range of chocolates to find a favorite), to highly controlled (e.g. tests requiring complex apparatus overseen by many scientists that hope to discover information about subatomic particles). Uses of experiments vary considerably between the natural and human sciences. Experiments typically include controls , which are designed to minimize the effects of variables other than the single independent variable . This increases

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1704-554: A receptionist would view the badge as useful, as it would help them locate members of staff during the day. Illustrating relations, researchers would also wear their badge due to informal pressures, such as not wanting to look like a spoil-sport, or not wanting to draw attention to themselves. Another finding is the resistance to change in a social organization. Staff members feel ill at ease when changing patterns of entitlement, obligation, respect, informal and formal hierarchy, and more. In summary, differences in attitude among members of

1846-422: A regular basis to assess hazards due to chemical handling and storage, electrical equipment, biohazards , hazardous waste management , chemical waste , housekeeping and emergency preparedness, radiation safety , ventilation as well as respiratory testing and indoor air quality . An important element of such audits is the review of regulatory compliance and the training of individuals who have access to or work in

1988-630: A room with one-way mirrors and hidden cameras in which to observe behavior. In some laboratories, such as those commonly used by computer scientists , computers (sometimes supercomputers ) are used for either simulations or the analysis of data . Scientists in other fields will still use other types of laboratories. Engineers use laboratories as well to design, build, and test technological devices. Scientific laboratories can be found as research room and learning spaces in schools and universities , industry , government , or military facilities, and even aboard ships and spacecraft . Despite

2130-431: A schedule where they conduct research on their own topic of interest for one day of the week, but for the rest they work on a given group project. Finance management is yet another organizational issue. The laboratory itself is a historically dated organizational model. It came about due to the observation that the quality of work of researchers who collaborate is overall greater than a researcher working in isolation. From

2272-465: A specific practical application as a goal, other than the deeper insight into the phenomema themselves. Applied physics is a general term for physics research and development that is intended for a particular use. An applied physics curriculum usually contains a few classes in an applied discipline, like geology or electrical engineering. It usually differs from engineering in that an applied physicist may not be designing something in particular, but rather

2414-426: A speed much less than the speed of light. These theories continue to be areas of active research today. Chaos theory , an aspect of classical mechanics, was discovered in the 20th century, three centuries after the original formulation of classical mechanics by Newton (1642–1727). These central theories are important tools for research into more specialized topics, and any physicist, regardless of their specialization,

2556-418: A strictly controlled test execution with a sensibility for the subjectivity and susceptibility of outcomes due to the nature of man is necessary. Furthermore, a critical view on the results and outcomes of earlier scholars is necessary: It is thus the duty of the man who studies the writings of scientists, if learning the truth is his goal, to make himself an enemy of all that he reads, and, applying his mind to

2698-399: A subfield of mechanics , is used in the building of bridges and other static structures. The understanding and use of acoustics results in sound control and better concert halls; similarly, the use of optics creates better optical devices. An understanding of physics makes for more realistic flight simulators , video games, and movies, and is often critical in forensic investigations. With

2840-466: A substantial treatise on " Physics " – in the 4th century BC. Aristotelian physics was influential for about two millennia. His approach mixed some limited observation with logical deductive arguments, but did not rely on experimental verification of deduced statements. Aristotle's foundational work in Physics, though very imperfect, formed a framework against which later thinkers further developed

2982-405: A test does not produce a measurable positive result. Most often the value of the negative control is treated as a "background" value to subtract from the test sample results. Sometimes the positive control takes the quadrant of a standard curve . An example that is often used in teaching laboratories is a controlled protein assay . Students might be given a fluid sample containing an unknown (to

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3124-466: A theory or hypothesis, but a theory can always be salvaged by appropriate ad hoc modifications at the expense of simplicity. An experiment must also control the possible confounding factors —any factors that would mar the accuracy or repeatability of the experiment or the ability to interpret the results. Confounding is commonly eliminated through scientific controls and/or, in randomized experiments , through random assignment . In engineering and

3266-517: Is a procedure carried out to support or refute a hypothesis , or determine the efficacy or likelihood of something previously untried. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated. Experiments vary greatly in goal and scale but always rely on repeatable procedure and logical analysis of the results. There also exist natural experimental studies . A child may carry out basic experiments to understand how things fall to

3408-432: Is a procedure similar to the actual experimental test but is known from previous experience to give a positive result. A negative control is known to give a negative result. The positive control confirms that the basic conditions of the experiment were able to produce a positive result, even if none of the actual experimental samples produce a positive result. The negative control demonstrates the base-line result obtained when

3550-413: Is clear-cut, but not always obvious. For example, mathematical physics is the application of mathematics in physics. Its methods are mathematical, but its subject is physical. The problems in this field start with a " mathematical model of a physical situation " (system) and a "mathematical description of a physical law" that will be applied to that system. Every mathematical statement used for solving has

3692-406: Is clearly impossible, when testing the hypothesis "Stars are collapsed clouds of hydrogen", to start out with a giant cloud of hydrogen, and then perform the experiment of waiting a few billion years for it to form a star. However, by observing various clouds of hydrogen in various states of collapse, and other implications of the hypothesis (for example, the presence of various spectral emissions from

3834-419: Is concerned with bodies acted on by forces and bodies in motion and may be divided into statics (study of the forces on a body or bodies not subject to an acceleration), kinematics (study of motion without regard to its causes), and dynamics (study of motion and the forces that affect it); mechanics may also be divided into solid mechanics and fluid mechanics (known together as continuum mechanics ),

3976-400: Is concerned with the most basic units of matter; this branch of physics is also known as high-energy physics because of the extremely high energies necessary to produce many types of particles in particle accelerators . On this scale, ordinary, commonsensical notions of space, time, matter, and energy are no longer valid. The two chief theories of modern physics present a different picture of

4118-425: Is expected to be literate in them. These include classical mechanics, quantum mechanics, thermodynamics and statistical mechanics , electromagnetism , and special relativity. Classical physics includes the traditional branches and topics that were recognized and well-developed before the beginning of the 20th century—classical mechanics, acoustics , optics , thermodynamics, and electromagnetism. Classical mechanics

4260-768: Is generally called a scientific instrument . The classical equipment includes tools such as Bunsen burners and microscopes as well as specialty equipment such as operant conditioning chambers , spectrophotometers and calorimeters . The title of laboratory is also used for certain other facilities where the processes or equipment used are similar to those in scientific laboratories. These notably include: In many laboratories, hazards are present. Laboratory hazards might include poisons ; infectious agents ; flammable , explosive , or radioactive materials; moving machinery ; extreme temperatures ; lasers , strong magnetic fields or high voltage . Therefore, safety precautions are vitally important. Rules exist to minimize

4402-429: Is generally concerned with matter and energy on the normal scale of observation, while much of modern physics is concerned with the behavior of matter and energy under extreme conditions or on a very large or very small scale. For example, atomic and nuclear physics study matter on the smallest scale at which chemical elements can be identified. The physics of elementary particles is on an even smaller scale since it

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4544-469: Is not enforced), but each class is aware and conforms to its existence. The degree of entitlement, which is also referred to as a staff's rights , affects social interaction between staff. By looking at the various interactions among staff members, we can determine their social position in the organization. As an example, administrators, in one lab of the study, do not have the right to ask the Locator where

4686-508: Is not unnecessarily kept at a very high level. Normally, ULT freezers are kept at −80 °C. One such device can consume up to the same amount of energy as a single-family household (25 kWh/day). Increasing the temperature to −70 °C makes it possible to use 40% less energy and still keep most samples safely stored. Minimizing the consumption of water can be achieved by changing from water-cooled condensers ( Dimroth condenser ) to air-cooled condensers ( Vigreux column ), which take advantage of

4828-593: Is often called the central science because of its role in linking the physical sciences. For example, chemistry studies properties, structures, and reactions of matter (chemistry's focus on the molecular and atomic scale distinguishes it from physics ). Structures are formed because particles exert electrical forces on each other, properties include physical characteristics of given substances, and reactions are bound by laws of physics, like conservation of energy , mass , and charge . Fundamental physics seeks to better explain and understand phenomena in all spheres, without

4970-926: Is possible depends on the observed correlation between explanatory variables in the observed data. When these variables are not well correlated, natural experiments can approach the power of controlled experiments. Usually, however, there is some correlation between these variables, which reduces the reliability of natural experiments relative to what could be concluded if a controlled experiment were performed. Also, because natural experiments usually take place in uncontrolled environments, variables from undetected sources are neither measured nor held constant, and these may produce illusory correlations in variables under study. Much research in several science disciplines, including economics , human geography , archaeology , sociology , cultural anthropology , geology , paleontology , ecology , meteorology , and astronomy , relies on quasi-experiments. For example, in astronomy it

5112-506: Is possible only in discrete steps proportional to their frequency. This, along with the photoelectric effect and a complete theory predicting discrete energy levels of electron orbitals , led to the theory of quantum mechanics improving on classical physics at very small scales. Quantum mechanics would come to be pioneered by Werner Heisenberg , Erwin Schrödinger and Paul Dirac . From this early work, and work in related fields,

5254-497: Is the phenomenon of translation , driven by the different backgrounds and levels of expertise of the people involved. Early instances of "laboratories" recorded in English involved alchemy and the preparation of medicines . The emergence of Big Science during World War II increased the size of laboratories and scientific equipment, introducing particle accelerators and similar devices. The earliest laboratory according to

5396-417: Is the step in the scientific method that helps people decide between two or more competing explanations—or hypotheses . These hypotheses suggest reasons to explain a phenomenon or predict the results of an action. An example might be the hypothesis that "if I release this ball, it will fall to the floor": this suggestion can then be tested by carrying out the experiment of letting go of the ball, and observing

5538-418: Is uncommon. In medicine and the social sciences , the prevalence of experimental research varies widely across disciplines. When used, however, experiments typically follow the form of the clinical trial , where experimental units (usually individual human beings) are randomly assigned to a treatment or control condition where one or more outcomes are assessed. In contrast to norms in the physical sciences,

5680-431: Is using physics or conducting physics research with the aim of developing new technologies or solving a problem. The approach is similar to that of applied mathematics . Applied physicists use physics in scientific research. For instance, people working on accelerator physics might seek to build better particle detectors for research in theoretical physics. Physics is used heavily in engineering. For example, statics,

5822-510: The English renaissance . He disagreed with the method of answering scientific questions by deduction —similar to Ibn al-Haytham —and described it as follows: "Having first determined the question according to his will, man then resorts to experience, and bending her to conformity with his placets, leads her about like a captive in a procession." Bacon wanted a method that relied on repeatable observations, or experiments. Notably, he first ordered

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5964-536: The Industrial Revolution as energy needs increased. The laws comprising classical physics remain widely used for objects on everyday scales travelling at non-relativistic speeds, since they provide a close approximation in such situations, and theories such as quantum mechanics and the theory of relativity simplify to their classical equivalents at such scales. Inaccuracies in classical mechanics for very small objects and very high velocities led to

6106-660: The Latin physica ('study of nature'), which itself is a borrowing of the Greek φυσική ( phusikḗ 'natural science'), a term derived from φύσις ( phúsis 'origin, nature, property'). Astronomy is one of the oldest natural sciences . Early civilizations dating before 3000 BCE, such as the Sumerians , ancient Egyptians , and the Indus Valley Civilisation , had a predictive knowledge and

6248-608: The Northern Hemisphere . Natural philosophy has its origins in Greece during the Archaic period (650 BCE – 480 BCE), when pre-Socratic philosophers like Thales rejected non-naturalistic explanations for natural phenomena and proclaimed that every event had a natural cause. They proposed ideas verified by reason and observation, and many of their hypotheses proved successful in experiment; for example, atomism

6390-637: The Scientific Revolution in the 17th century, these natural sciences branched into separate research endeavors. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry , and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in these and other academic disciplines such as mathematics and philosophy. Advances in physics often enable new technologies . For example, advances in

6532-619: The Standard Model of particle physics was derived. Following the discovery of a particle with properties consistent with the Higgs boson at CERN in 2012, all fundamental particles predicted by the standard model, and no others, appear to exist; however, physics beyond the Standard Model , with theories such as supersymmetry , is an active area of research. Areas of mathematics in general are important to this field, such as

6674-416: The branches of science . For example, agricultural research frequently uses randomized experiments (e.g., to test the comparative effectiveness of different fertilizers), while experimental economics often involves experimental tests of theorized human behaviors without relying on random assignment of individuals to treatment and control conditions. One of the first methodical approaches to experiments in

6816-439: The camera obscura (his thousand-year-old version of the pinhole camera ) and delved further into the way the eye itself works. Using the knowledge of previous scholars, he began to explain how light enters the eye. He asserted that the light ray is focused, but the actual explanation of how light projected to the back of the eye had to wait until 1604. His Treatise on Light explained the camera obscura , hundreds of years before

6958-579: The empirical world. This is usually combined with the claim that the laws of logic express universal regularities found in the structural features of the world, which may explain the peculiar relation between these fields. Physics uses mathematics to organise and formulate experimental results. From those results, precise or estimated solutions are obtained, or quantitative results, from which new predictions can be made and experimentally confirmed or negated. The results from physics experiments are numerical data, with their units of measure and estimates of

7100-469: The non-profit organisation my green lab . Organization of laboratories is an area of focus in sociology. Scientists consider how their work should be organized, which could be based on themes, teams, projects or fields of expertise. Work is divided, not only between different jobs of the laboratory such as the researchers, engineers and technicians , but also in terms of autonomy (should the work be individual or in groups). For example, one research group has

7242-449: The physical sciences , experiments are a primary component of the scientific method. They are used to test theories and hypotheses about how physical processes work under particular conditions (e.g., whether a particular engineering process can produce a desired chemical compound). Typically, experiments in these fields focus on replication of identical procedures in hopes of producing identical results in each replication. Random assignment

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7384-543: The standard consensus that the laws of physics are universal and do not change with time, physics can be used to study things that would ordinarily be mired in uncertainty . For example, in the study of the origin of the Earth, a physicist can reasonably model Earth's mass, temperature, and rate of rotation, as a function of time allowing the extrapolation forward or backward in time and so predict future or prior events. It also allows for simulations in engineering that speed up

7526-443: The "Laboratory Standard". Under this standard, a laboratory is required to produce a Chemical Hygiene Plan (CHP) which addresses the specific hazards found in its location, and its approach to them. In determining the proper Chemical Hygiene Plan for a particular business or laboratory, it is necessary to understand the requirements of the standard, evaluation of the current safety, health and environmental practices and assessment of

7668-435: The 16th and 17th centuries, and Isaac Newton 's discovery and unification of the laws of motion and universal gravitation (that would come to bear his name). Newton also developed calculus , the mathematical study of continuous change, which provided new mathematical methods for solving physical problems. The discovery of laws in thermodynamics , chemistry , and electromagnetics resulted from research efforts during

7810-499: The 1950s, the laboratory has evolved from being an educational tool used by teachers to attract the top students into research, into an organizational model allowing a high level of scientific productivity. Some forms of organization in laboratories include: There are three main factors that contribute to the organizational form of a laboratory : Other forms of organization include social organization. A study by Richard H.R. Harper, involving two laboratories, will help elucidate

7952-554: The 19th century, and many new kinds of equipment were developed in the 20th century. A 16th century underground alchemical laboratory was accidentally discovered in the year 2002. Rudolf II, Holy Roman Emperor was believed to be the owner. The laboratory is called Speculum Alchemiae and is preserved as a museum in Prague . Laboratory techniques are the set of procedures used on natural sciences such as chemistry , biology , physics to conduct an experiment; while some of them involve

8094-425: The accuracy of the hypotheses. Experiments can be also designed to estimate spillover effects onto nearby untreated units. The term "experiment" usually implies a controlled experiment, but sometimes controlled experiments are prohibitively difficult, impossible, unethical or illegal. In this case researchers resort to natural experiments or quasi-experiments . Natural experiments rely solely on observations of

8236-410: The advantage that outcomes are observed in a natural setting rather than in a contrived laboratory environment. For this reason, field experiments are sometimes seen as having higher external validity than laboratory experiments. However, like natural experiments, field experiments suffer from the possibility of contamination: experimental conditions can be controlled with more precision and certainty in

8378-571: The amount of some cell or substance in the blood, physical strength or endurance, etc.) and not based on a subject's or a professional observer's opinion. In this way, the design of an observational study can render the results more objective and therefore, more convincing. By placing the distribution of the independent variable(s) under the control of the researcher, an experiment—particularly when it involves human subjects —introduces potential ethical considerations, such as balancing benefit and harm, fairly distributing interventions (e.g., treatments for

8520-511: The attacks from invaders and continued to advance various fields of learning, including physics. In the sixth century, Isidore of Miletus created an important compilation of Archimedes ' works that are copied in the Archimedes Palimpsest . In sixth-century Europe John Philoponus , a Byzantine scholar, questioned Aristotle 's teaching of physics and noted its flaws. He introduced the theory of impetus . Aristotle's physics

8662-441: The centuries that followed, people who applied the scientific method in different areas made important advances and discoveries. For example, Galileo Galilei (1564–1642) accurately measured time and experimented to make accurate measurements and conclusions about the speed of a falling body. Antoine Lavoisier (1743–1794), a French chemist, used experiment to describe new areas, such as combustion and biochemistry and to develop

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8804-502: The concept of social organization in laboratories. The main subject of the study revolved around the relationship between the staff of a laboratory (researchers, administrators, receptionists, technicians, etc.) and their Locator. A Locator is an employee of a Laboratory who is in charge of knowing where each member of the laboratory currently is, based on a unique signal emitted from the badge of each staff member. The study describes social relationships among different classes of jobs, such as

8946-434: The concepts of space, time, and matter from that presented by classical physics. Classical mechanics approximates nature as continuous, while quantum theory is concerned with the discrete nature of many phenomena at the atomic and subatomic level and with the complementary aspects of particles and waves in the description of such phenomena. The theory of relativity is concerned with the description of phenomena that take place in

9088-409: The constant speed predicted by Maxwell's equations of electromagnetism. This discrepancy was corrected by Einstein's theory of special relativity , which replaced classical mechanics for fast-moving bodies and allowed for a constant speed of light. Black-body radiation provided another problem for classical physics, which was corrected when Planck proposed that the excitation of material oscillators

9230-551: The core and margins of its content, attack it from every side. He should also suspect himself as he performs his critical examination of it, so that he may avoid falling into either prejudice or leniency. Thus, a comparison of earlier results with the experimental results is necessary for an objective experiment—the visible results being more important. In the end, this may mean that an experimental researcher must find enough courage to discard traditional opinions or results, especially if these results are not experimental but results from

9372-437: The covariates that can be identified. Researchers attempt to reduce the biases of observational studies with matching methods such as propensity score matching , which require large populations of subjects and extensive information on covariates. However, propensity score matching is no longer recommended as a technique because it can increase, rather than decrease, bias. Outcomes are also quantified when possible (bone density,

9514-483: The data in light of them (though this may be rare when social phenomena are under examination). For an observational science to be valid, the experimenter must know and account for confounding factors. In these situations, observational studies have value because they often suggest hypotheses that can be tested with randomized experiments or by collecting fresh data. Fundamentally, however, observational studies are not experiments. By definition, observational studies lack

9656-516: The design and analysis of experiments occurred in the early 20th century, with contributions from statisticians such as Ronald Fisher (1890–1962), Jerzy Neyman (1894–1981), Oscar Kempthorne (1919–2000), Gertrude Mary Cox (1900–1978), and William Gemmell Cochran (1909–1980), among others. Experiments might be categorized according to a number of dimensions, depending upon professional norms and standards in different fields of study. In some disciplines (e.g., psychology or political science ),

9798-466: The development of a new technology. There is also considerable interdisciplinarity , so many other important fields are influenced by physics (e.g., the fields of econophysics and sociophysics ). Physicists use the scientific method to test the validity of a physical theory . By using a methodical approach to compare the implications of a theory with the conclusions drawn from its related experiments and observations, physicists are better able to test

9940-429: The development of modern physics in the 20th century. Modern physics began in the early 20th century with the work of Max Planck in quantum theory and Albert Einstein 's theory of relativity. Both of these theories came about due to inaccuracies in classical mechanics in certain situations. Classical mechanics predicted that the speed of light depends on the motion of the observer, which could not be resolved with

10082-407: The development of new experiments (and often related equipment). Physicists who work at the interplay of theory and experiment are called phenomenologists , who study complex phenomena observed in experiment and work to relate them to a fundamental theory . Theoretical physics has historically taken inspiration from philosophy; electromagnetism was unified this way. Beyond the known universe,

10224-407: The discipline, experiments can be conducted to accomplish different but not mutually exclusive goals: test theories, search for and document phenomena, develop theories, or advise policymakers. These goals also relate differently to validity concerns . A controlled experiment often compares the results obtained from experimental samples against control samples, which are practically identical to

10366-443: The effect of the tested variables. In the scientific method , an experiment is an empirical procedure that arbitrates competing models or hypotheses . Researchers also use experimentation to test existing theories or new hypotheses to support or disprove them. An experiment usually tests a hypothesis , which is an expectation about how a particular process or phenomenon works. However, an experiment may also aim to answer

10508-495: The effect of the treatment (exposure) from the effects of the other covariates, most of which have not been measured. The mathematical models used to analyze such data must consider each differing covariate (if measured), and results are not meaningful if a covariate is neither randomized nor included in the model. To avoid conditions that render an experiment far less useful, physicians conducting medical trials—say for U.S. Food and Drug Administration approval—quantify and randomize

10650-413: The effects of substandard or harmful treatments, such as the effects of ingesting arsenic on human health. To understand the effects of such exposures, scientists sometimes use observational studies to understand the effects of those factors. Even when experimental research does not directly involve human subjects, it may still present ethical concerns. For example, the nuclear bomb experiments conducted by

10792-682: The errors in the measurements. Technologies based on mathematics, like computation have made computational physics an active area of research. Ontology is a prerequisite for physics, but not for mathematics. It means physics is ultimately concerned with descriptions of the real world, while mathematics is concerned with abstract patterns, even beyond the real world. Thus physics statements are synthetic, while mathematical statements are analytic. Mathematics contains hypotheses, while physics contains theories. Mathematics statements have to be only logically true, while predictions of physics statements must match observed and experimental data. The distinction

10934-470: The experiment is to measure the response to the stimulus by a test method . In the design of experiments , two or more "treatments" are applied to estimate the difference between the mean responses for the treatments. For example, an experiment on baking bread could estimate the difference in the responses associated with quantitative variables, such as the ratio of water to flour, and with qualitative variables, such as strains of yeast. Experimentation

11076-414: The experimental sample except for the one aspect whose effect is being tested (the independent variable ). A good example would be a drug trial. The sample or group receiving the drug would be the experimental group ( treatment group ); and the one receiving the placebo or regular treatment would be the control one. In many laboratory experiments it is good practice to have several replicate samples for

11218-857: The field of theoretical physics also deals with hypothetical issues, such as parallel universes , a multiverse , and higher dimensions . Theorists invoke these ideas in hopes of solving particular problems with existing theories; they then explore the consequences of these ideas and work toward making testable predictions. Experimental physics expands, and is expanded by, engineering and technology. Experimental physicists who are involved in basic research design and perform experiments with equipment such as particle accelerators and lasers , whereas those involved in applied research often work in industry, developing technologies such as magnetic resonance imaging (MRI) and transistors . Feynman has noted that experimentalists may seek areas that have not been explored well by theorists. Experiment An experiment

11360-415: The field. His approach is entirely superseded today. He explained ideas such as motion (and gravity ) with the theory of four elements . Aristotle believed that each of the four classical elements (air, fire, water, earth) had its own natural place. Because of their differing densities, each element will revert to its own specific place in the atmosphere. So, because of their weights, fire would be at

11502-429: The first scholars to use an inductive-experimental method for achieving results. In his Book of Optics he describes the fundamentally new approach to knowledge and research in an experimental sense: We should, that is, recommence the inquiry into its principles and premisses, beginning our investigation with an inspection of the things that exist and a survey of the conditions of visible objects. We should distinguish

11644-413: The focus is typically on the average treatment effect (the difference in outcomes between the treatment and control groups) or another test statistic produced by the experiment. A single study typically does not involve replications of the experiment, but separate studies may be aggregated through systematic review and meta-analysis . There are various differences in experimental practice in each of

11786-482: The ground, while teams of scientists may take years of systematic investigation to advance their understanding of a phenomenon. Experiments and other types of hands-on activities are very important to student learning in the science classroom. Experiments can raise test scores and help a student become more engaged and interested in the material they are learning, especially when used over time. Experiments can vary from personal and informal natural comparisons (e.g. tasting

11928-402: The groups and that the groups should respond in the same manner if given the same treatment. This equivalency is determined by statistical methods that take into account the amount of variation between individuals and the number of individuals in each group. In fields such as microbiology and chemistry , where there is very little variation between individuals and the group size is easily in

12070-460: The hazards. The CHP must be reviewed annually. Many schools and businesses employ safety, health, and environmental specialists, such as a Chemical Hygiene Officer (CHO) to develop, manage, and evaluate their CHP. Additionally, third party review is also used to provide an objective "outside view" which provides a fresh look at areas and problems that may be taken for granted or overlooked due to habit. Inspections and audits like also be conducted on

12212-478: The individual's risk, and safety equipment is used to protect the lab users from injury or to assist in responding to an emergency . The Occupational Safety and Health Administration (OSHA) in the United States, recognizing the unique characteristics of the laboratory workplace, has tailored a standard for occupational exposure to hazardous chemicals in laboratories. This standard is often referred to as

12354-452: The lab. Yet some phenomena (e.g., voter turnout in an election) cannot be easily studied in a laboratory. An observational study is used when it is impractical, unethical, cost-prohibitive (or otherwise inefficient) to fit a physical or social system into a laboratory setting, to completely control confounding factors, or to apply random assignment. It can also be used when confounding factors are either limited or known well enough to analyze

12496-421: The laboratory are explained by social organization: A person's attitudes are intimately related to the role they have in an organization. This hierarchy helps understand information distribution, control, and attitudes towards technologies in the laboratory. Physics Physics is the scientific study of matter , its fundamental constituents , its motion and behavior through space and time , and

12638-443: The laboratory. Training is critical to the ongoing safe operation of the laboratory facility. Educators, staff and management must be engaged in working to reduce the likelihood of accidents, injuries and potential litigation. Efforts are made to ensure laboratory safety videos are both relevant and engaging. The effects of climate change are becoming more of a concern for organizations, and mitigation strategies are being sought by

12780-457: The large surface area to cool. The use of ovens is very helpful to dry glassware, but those installations can consume a lot of energy. Employing timers to regulate their use during nights and weekends, can reduce their impact on energy consumption enormously. The disposal of chemically/biologically contaminated waste requires a lot of energy. Regular waste however requires much less energy or can even be recycled to some degree. Not every object in

12922-400: The latter include such branches as hydrostatics , hydrodynamics and pneumatics . Acoustics is the study of how sound is produced, controlled, transmitted and received. Important modern branches of acoustics include ultrasonics , the study of sound waves of very high frequency beyond the range of human hearing; bioacoustics , the physics of animal calls and hearing, and electroacoustics ,

13064-490: The laws of classical physics accurately describe systems whose important length scales are greater than the atomic scale and whose motions are much slower than the speed of light. Outside of this domain, observations do not match predictions provided by classical mechanics. Einstein contributed the framework of special relativity, which replaced notions of absolute time and space with spacetime and allowed an accurate description of systems whose components have speeds approaching

13206-410: The light of stars), we can collect data we require to support the hypothesis. An early example of this type of experiment was the first verification in the 17th century that light does not travel from place to place instantaneously, but instead has a measurable speed. Observation of the appearance of the moons of Jupiter were slightly delayed when Jupiter was farther from Earth, as opposed to when Jupiter

13348-423: The major contributor to this high energy consumption are fume hoods. Significant impact can be achieved by keeping the opening height as low as possible when working and keeping them closed when not in use. One possibility to help with this, could be to install automatic systems, which close the hoods after an inactivity period of a certain length and turn off the lights as well. So the flow can be regulated better and

13490-412: The manipulation of audible sound waves using electronics. Optics, the study of light, is concerned not only with visible light but also with infrared and ultraviolet radiation , which exhibit all of the phenomena of visible light except visibility, e.g., reflection, refraction, interference, diffraction, dispersion, and polarization of light. Heat is a form of energy, the internal energy possessed by

13632-403: The manipulation required for Baconian experiments . In addition, observational studies (e.g., in biological or social systems) often involve variables that are difficult to quantify or control. Observational studies are limited because they lack the statistical properties of randomized experiments. In a randomized experiment, the method of randomization specified in the experimental protocol guides

13774-454: The mean for each group is expected to be the same. For any randomized trial, some variation from the mean is expected, of course, but the randomization ensures that the experimental groups have mean values that are close, due to the central limit theorem and Markov's inequality . With inadequate randomization or low sample size, the systematic variation in covariates between the treatment groups (or exposure groups) makes it difficult to separate

13916-490: The millions, these statistical methods are often bypassed and simply splitting a solution into equal parts is assumed to produce identical sample groups. Once equivalent groups have been formed, the experimenter tries to treat them identically except for the one variable that he or she wishes to isolate. Human experimentation requires special safeguards against outside variables such as the placebo effect . Such experiments are generally double blind , meaning that neither

14058-704: The modern development of photography. The seven-volume Book of Optics ( Kitab al-Manathir ) influenced thinking across disciplines from the theory of visual perception to the nature of perspective in medieval art, in both the East and the West, for more than 600 years. This included later European scholars and fellow polymaths, from Robert Grosseteste and Leonardo da Vinci to Johannes Kepler . The translation of The Book of Optics had an impact on Europe. From it, later European scholars were able to build devices that replicated those Ibn al-Haytham had built and understand

14200-460: The modern sense is visible in the works of the Arab mathematician and scholar Ibn al-Haytham . He conducted his experiments in the field of optics—going back to optical and mathematical problems in the works of Ptolemy —by controlling his experiments due to factors such as self-criticality, reliance on visible results of the experiments as well as a criticality in terms of earlier results. He was one of

14342-468: The other Philoponus' criticism of Aristotelian principles of physics served as an inspiration for Galileo Galilei ten centuries later, during the Scientific Revolution . Galileo cited Philoponus substantially in his works when arguing that Aristotelian physics was flawed. In the 1300s Jean Buridan , a teacher in the faculty of arts at the University of Paris , developed the concept of impetus. It

14484-459: The other, you will see that the ratio of the times required for the motion does not depend on the ratio of the weights, but that the difference in time is a very small one. And so, if the difference in the weights is not considerable, that is, of one is, let us say, double the other, there will be no difference, or else an imperceptible difference, in time, though the difference in weight is by no means negligible, with one body weighing twice as much as

14626-572: The particles of which a substance is composed; thermodynamics deals with the relationships between heat and other forms of energy. Electricity and magnetism have been studied as a single branch of physics since the intimate connection between them was discovered in the early 19th century; an electric current gives rise to a magnetic field , and a changing magnetic field induces an electric current. Electrostatics deals with electric charges at rest, electrodynamics with moving charges, and magnetostatics with magnetic poles at rest. Classical physics

14768-602: The positions of the planets . According to Asger Aaboe , the origins of Western astronomy can be found in Mesopotamia , and all Western efforts in the exact sciences are descended from late Babylonian astronomy . Egyptian astronomers left monuments showing knowledge of the constellations and the motions of the celestial bodies, while Greek poet Homer wrote of various celestial objects in his Iliad and Odyssey ; later Greek astronomers provided names, which are still used today, for most constellations visible from

14910-497: The present evidence is a home laboratory of Pythagoras of Samos, the well-known Greek philosopher and scientist. This laboratory was created when Pythagoras conducted an experiment about tones of sound and vibration of string. In the painting of Louis Pasteur by Albert Edelfelt in 1885, Louis Pasteur is shown comparing a note in his left hand with a bottle filled with a solid in his right hand, and not wearing any personal protective equipment . Researching in teams started in

15052-539: The properties of particulars, and gather by induction what pertains to the eye when vision takes place and what is found in the manner of sensation to be uniform, unchanging, manifest and not subject to doubt. After which we should ascend in our inquiry and reasonings, gradually and orderly, criticizing premisses and exercising caution in regard to conclusions—our aim in all that we make subject to inspection and review being to employ justice, not to follow prejudice, and to take care in all that we judge and criticize that we seek

15194-409: The reagents for the protein assay but no protein. In this example, all samples are performed in duplicate. The assay is a colorimetric assay in which a spectrophotometer can measure the amount of protein in samples by detecting a colored complex formed by the interaction of protein molecules and molecules of an added dye. In the illustration, the results for the diluted test samples can be compared to

15336-399: The related entities of energy and force . Physics is one of the most fundamental scientific disciplines. A scientist who specializes in the field of physics is called a physicist . Physics is one of the oldest academic disciplines . Over much of the past two millennia, physics, chemistry , biology , and certain branches of mathematics were a part of natural philosophy , but during

15478-421: The relationship between researchers and the Locator. It does not describe the social relationship between employees within a class, such as the relationship between researchers. Through ethnographic studies, one finding is that, among the personnel, each class (researchers, administrators...) has a different degree of entitlement, which varies per laboratory. Entitlement can be both formal or informal (meaning it

15620-455: The reliability of the results, often through a comparison between control measurements and the other measurements. Scientific controls are a part of the scientific method . Ideally, all variables in an experiment are controlled (accounted for by the control measurements) and none are uncontrolled. In such an experiment, if all controls work as expected, it is possible to conclude that the experiment works as intended, and that results are due to

15762-561: The research community. While many laboratories are used to perform research to find innovative solutions to this global challenge, sustainable working practices in the labs are also contributing factors towards a greener environment. Many labs are already trying to minimize their environmental impact by reducing energy consumption, recycling, and implementing waste sorting processes to ensure correct disposal. Research labs featuring energy-intensive equipment, use up to three to five times more energy per square meter than office areas. Presumably

15904-438: The researchers currently are, as they are not entitled to such information. On the other hand, researchers do have access to this type of information. So a consequence of this social hierarchy is that the Locator discloses various degrees of information, based on the staff member and their rights. The Locator does not want to disclose information that could jeopardize his relationship with the members of staff. The Locator adheres to

16046-747: The results of the observational studies are inconsistent and also differ from the results of experiments. For example, epidemiological studies of colon cancer consistently show beneficial correlations with broccoli consumption, while experiments find no benefit. A particular problem with observational studies involving human subjects is the great difficulty attaining fair comparisons between treatments (or exposures), because such studies are prone to selection bias , and groups receiving different treatments (exposures) may differ greatly according to their covariates (age, height, weight, medications, exercise, nutritional status, ethnicity, family medical history, etc.). In contrast, randomization implies that for each covariate,

16188-422: The results of the standard curve (the blue line in the illustration) to estimate the amount of protein in the unknown sample. Controlled experiments can be performed when it is difficult to exactly control all the conditions in an experiment. In this case, the experiment begins by creating two or more sample groups that are probabilistically equivalent, which means that measurements of traits should be similar among

16330-407: The results. Formally, a hypothesis is compared against its opposite or null hypothesis ("if I release this ball, it will not fall to the floor"). The null hypothesis is that there is no explanation or predictive power of the phenomenon through the reasoning that is being investigated. Once hypotheses are defined, an experiment can be carried out and the results analysed to confirm, refute, or define

16472-479: The rights of each class. Social hierarchy is also related to attitudes towards technologies. This was inferred based on the attitude of various jobs towards their lab badge. Their attitude depended on how that job viewed their badge from a standpoint of utility, (how is the badge useful for my job) morality (what are my morals on privacy, as it relates to being tracked by this badge) and relations (how will I be seen by others if I refuse to wear this badge). For example,

16614-504: The scientific method as we understand it today. There remains simple experience; which, if taken as it comes, is called accident, if sought for, experiment. The true method of experience first lights the candle [hypothesis], and then by means of the candle shows the way [arranges and delimits the experiment]; commencing as it does with experience duly ordered and digested, not bungling or erratic, and from it deducing axioms [theories], and from established axioms again new experiments. In

16756-440: The speed being proportional to the weight and the speed of the object that is falling depends inversely on the density object it is falling through (e.g. density of air). He also stated that, when it comes to violent motion (motion of an object when a force is applied to it by a second object) that the speed that object moves, will only be as fast or strong as the measure of force applied to it. The problem of motion and its causes

16898-412: The speed of light. Planck, Schrödinger, and others introduced quantum mechanics, a probabilistic notion of particles and interactions that allowed an accurate description of atomic and subatomic scales. Later, quantum field theory unified quantum mechanics and special relativity. General relativity allowed for a dynamical, curved spacetime, with which highly massive systems and the large-scale structure of

17040-417: The statistical analysis, which is usually specified also by the experimental protocol. Without a statistical model that reflects an objective randomization, the statistical analysis relies on a subjective model. Inferences from subjective models are unreliable in theory and practice. In fact, there are several cases where carefully conducted observational studies consistently give wrong results, that is, where

17182-463: The student) amount of protein. It is their job to correctly perform a controlled experiment in which they determine the concentration of protein in the fluid sample (usually called the "unknown sample"). The teaching lab would be equipped with a protein standard solution with a known protein concentration. Students could make several positive control samples containing various dilutions of the protein standard. Negative control samples would contain all of

17324-412: The study of probabilities and groups . Physics deals with a wide variety of systems, although certain theories are used by all physicists. Each of these theories was experimentally tested numerous times and found to be an adequate approximation of nature. For instance, the theory of classical mechanics accurately describes the motion of objects, provided they are much larger than atoms and moving at

17466-461: The test being performed and have both a positive control and a negative control . The results from replicate samples can often be averaged, or if one of the replicates is obviously inconsistent with the results from the other samples, it can be discarded as being the result of an experimental error (some step of the test procedure may have been mistakenly omitted for that sample). Most often, tests are done in duplicate or triplicate. A positive control

17608-403: The theory of conservation of mass (matter). Louis Pasteur (1822–1895) used the scientific method to disprove the prevailing theory of spontaneous generation and to develop the germ theory of disease . Because of the importance of controlling potentially confounding variables, the use of well-designed laboratory experiments is preferred when possible. A considerable amount of progress on

17750-444: The top, air underneath fire, then water, then lastly earth. He also stated that when a small amount of one element enters the natural place of another, the less abundant element will automatically go towards its own natural place. For example, if there is a fire on the ground, the flames go up into the air in an attempt to go back into its natural place where it belongs. His laws of motion included: that heavier objects will fall faster,

17892-523: The truth and not to be swayed by opinion. We may in this way eventually come to the truth that gratifies the heart and gradually and carefully reach the end at which certainty appears; while through criticism and caution we may seize the truth that dispels disagreement and resolves doubtful matters. For all that, we are not free from that human turbidity which is in the nature of man; but we must do our best with what we possess of human power. From God we derive support in all things. According to his explanation,

18034-600: The underlying notion of the lab as a confined space for experts, the term "laboratory" is also increasingly applied to workshop spaces such as Living Labs , Fab Labs , or Hackerspaces , in which people meet to work on societal problems or make prototypes , working collaboratively or sharing resources. This development is inspired by new, participatory approaches to science and innovation and relies on user-centred design methods and concepts like Open innovation or User innovation ,. One distinctive feature of work in Open Labs

18176-423: The understanding of electromagnetism , solid-state physics , and nuclear physics led directly to the development of technologies that have transformed modern society, such as television, computers, domestic appliances , and nuclear weapons ; advances in thermodynamics led to the development of industrialization; and advances in mechanics inspired the development of calculus . The word physics comes from

18318-423: The universe can be well-described. General relativity has not yet been unified with the other fundamental descriptions; several candidate theories of quantum gravity are being developed. Physics, as with the rest of science, relies on the philosophy of science and its " scientific method " to advance knowledge of the physical world. The scientific method employs a priori and a posteriori reasoning as well as

18460-644: The university of Edingburgh. Furthermore, several networks have emerged such as Green Your Lab , Towards greener research , the UK-based network LEAN , the Max-Planck-Sustainability network , and national platforms such as green labs austria and green labs NL . More university independent efforts and resources include the Laboratory Efficiency Assessment Framework , the think-tank labos1point5 and

18602-573: The use of Bayesian inference to measure the validity of a given theory. Study of the philosophical issues surrounding physics, the philosophy of physics , involves issues such as the nature of space and time , determinism , and metaphysical outlooks such as empiricism , naturalism , and realism . Many physicists have written about the philosophical implications of their work, for instance Laplace , who championed causal determinism , and Erwin Schrödinger , who wrote on quantum mechanics. The mathematical physicist Roger Penrose has been called

18744-415: The use of complex laboratory equipment from laboratory glassware to electrical devices, and others require more specific or expensive supplies. Laboratory equipment refers to the various tools and equipment used by scientists working in a laboratory. Laboratory equipment is generally used to either perform an experiment or to take measurements and gather data . Larger or more sophisticated equipment

18886-988: The validity of a theory in a logical, unbiased, and repeatable way. To that end, experiments are performed and observations are made in order to determine the validity or invalidity of a theory. A scientific law is a concise verbal or mathematical statement of a relation that expresses a fundamental principle of some theory, such as Newton's law of universal gravitation. Theorists seek to develop mathematical models that both agree with existing experiments and successfully predict future experimental results, while experimentalists devise and perform experiments to test theoretical predictions and explore new phenomena. Although theory and experiment are developed separately, they strongly affect and depend upon each other. Progress in physics frequently comes about when experimental results defy explanation by existing theories, prompting intense focus on applicable modelling, and when new theories generate experimentally testable predictions , which inspire

19028-443: The variables of the system under study, rather than manipulation of just one or a few variables as occurs in controlled experiments. To the degree possible, they attempt to collect data for the system in such a way that contribution from all variables can be determined, and where the effects of variation in certain variables remain approximately constant so that the effects of other variables can be discerned. The degree to which this

19170-422: The volunteer nor the researcher knows which individuals are in the control group or the experimental group until after all of the data have been collected. This ensures that any effects on the volunteer are due to the treatment itself and are not a response to the knowledge that he is being treated. In human experiments, researchers may give a subject (person) a stimulus that the subject responds to. The goal of

19312-579: The way vision works. Physics became a separate science when early modern Europeans used experimental and quantitative methods to discover what are now considered to be the laws of physics . Major developments in this period include the replacement of the geocentric model of the Solar System with the heliocentric Copernican model , the laws governing the motion of planetary bodies (determined by Kepler between 1609 and 1619), Galileo's pioneering work on telescopes and observational astronomy in

19454-399: The works of many scientists like Ibn Sahl , Al-Kindi , Ibn al-Haytham , Al-Farisi and Avicenna . The most notable work was The Book of Optics (also known as Kitāb al-Manāẓir), written by Ibn al-Haytham, in which he presented the alternative to the ancient Greek idea about vision. In his Treatise on Light as well as in his Kitāb al-Manāẓir , he presented a study of the phenomenon of

19596-550: Was a step toward the modern ideas of inertia and momentum. Islamic scholarship inherited Aristotelian physics from the Greeks and during the Islamic Golden Age developed it further, especially placing emphasis on observation and a priori reasoning, developing early forms of the scientific method . The most notable innovations under Islamic scholarship were in the field of optics and vision, which came from

19738-503: Was closer to Earth; and this phenomenon was used to demonstrate that the difference in the time of appearance of the moons was consistent with a measurable speed. Field experiments are so named to distinguish them from laboratory experiments, which enforce scientific control by testing a hypothesis in the artificial and highly controlled setting of a laboratory. Often used in the social sciences, and especially in economic analyses of education and health interventions, field experiments have

19880-513: Was found to be correct approximately 2000 years after it was proposed by Leucippus and his pupil Democritus . During the classical period in Greece (6th, 5th and 4th centuries BCE) and in Hellenistic times , natural philosophy developed along many lines of inquiry. Aristotle ( Greek : Ἀριστοτέλης , Aristotélēs ) (384–322 BCE), a student of Plato , wrote on many subjects, including

20022-417: Was not scrutinized until Philoponus appeared; unlike Aristotle, who based his physics on verbal argument, Philoponus relied on observation. On Aristotle's physics Philoponus wrote: But this is completely erroneous, and our view may be corroborated by actual observation more effectively than by any sort of verbal argument. For if you let fall from the same height two weights of which one is many times as heavy as

20164-548: Was studied carefully, leading to the philosophical notion of a " prime mover " as the ultimate source of all motion in the world (Book 8 of his treatise Physics ). The Western Roman Empire fell to invaders and internal decay in the fifth century, resulting in a decline in intellectual pursuits in western Europe. By contrast, the Eastern Roman Empire (usually known as the Byzantine Empire ) resisted

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