Observation in the natural sciences is an act or instance of noticing or perceiving and the acquisition of information from a primary source . In living beings, observation employs the senses . In science , observation can also involve the perception and recording of data via the use of scientific instruments . The term may also refer to any data collected during the scientific activity. Observations can be qualitative , that is, the absence or presence of a property is noted and the observed phenomenon described, or quantitative if a numerical value is attached to the observed phenomenon by counting or measuring .
33-816: [REDACTED] Look up observant in Wiktionary, the free dictionary. Observant may refer to: Making an observation Having observance of a holiday (public, religious, etc.) religious law or spiritual practice (worship, diet, taboo, etc.) Observantism , late medieval movement among Catholic religious orders The Observants , one-eyed ghosts in Danny Phantom Ob(Servant) , 2008 death metal album by Psycroptic Rite of Strict Observance , former Rite of Freemasonry See also [ edit ] Observer (disambiguation) Observance (disambiguation) Topics referred to by
66-458: A complex, unconscious process of abstraction , in which certain details of the incoming sense data are noticed and remembered, and the rest is forgotten. What is kept and what is thrown away depends on an internal model or representation of the world, called by psychologists a schema , that is built up over our entire lives. The data is fitted into this schema. Later when events are remembered, memory gaps may even be filled by "plausible" data
99-490: A multitude of colored plants and plant parts, including from leaves ( red cabbage ); flowers ( geranium , poppy , or rose petals); berries ( blueberries , blackcurrant ); and stems ( rhubarb ). Extracting anthocyanins from household plants, especially red cabbage , to form a crude pH indicator is a popular introductory chemistry demonstration. Litmus , used by alchemists in the Middle Ages and still readily available,
132-464: Is a halochromic chemical compound added in small amounts to a solution so the pH ( acidity or basicity ) of the solution can be determined visually or spectroscopically by changes in absorption and/or emission properties. Hence, a pH indicator is a chemical detector for hydronium ions (H 3 O ) or hydrogen ions (H ) in the Arrhenius model . Normally, the indicator causes the color of
165-580: Is a naturally occurring pH indicator made from a mixture of lichen species, particularly Roccella tinctoria . The word litmus is literally from 'colored moss' in Old Norse (see Litr ). The color changes between red in acid solutions and blue in alkalis. The term 'litmus test' has become a widely used metaphor for any test that purports to distinguish authoritatively between alternatives. Hydrangea macrophylla flowers can change color depending on soil acidity. In acid soils, chemical reactions occur in
198-588: Is different from Wikidata All article disambiguation pages All disambiguation pages Observation The scientific method requires observations of natural phenomena to formulate and test hypotheses . It consists of the following steps: Observations play a role in the second and fifth steps of the scientific method. However, the need for reproducibility requires that observations by different observers can be comparable. Human sense impressions are subjective and qualitative , making them difficult to record or compare. The use of measurement
231-508: Is not normally possible to check the air pressure in an automobile tire without letting out some of the air, thereby changing the pressure. However, in most fields of science, it is possible to reduce the effects of observation to insignificance by using better instruments. Considered as a physical process itself, all forms of observation (human or instrumental) involve amplification and are thus thermodynamically irreversible processes , increasing entropy . In some specific fields of science,
264-463: Is the acidic form and "Ind " is the conjugate base of the indicator. Vice versa for basic pH indicators in aqueous solutions: where "IndOH" stands for the basic form and "Ind " for the conjugate acid of the indicator. The ratio of concentration of conjugate acid/base to concentration of the acidic/basic indicator determines the pH (or pOH) of the solution and connects the color to the pH (or pOH) value. For pH indicators that are weak electrolytes,
297-576: Is the discovery of x-rays . It can also result in erroneous scientific support for widely held cultural myths, on the other hand, as in the scientific racism that supported ideas of racial superiority in the early 20th century. Correct scientific technique emphasizes careful recording of observations, separating experimental observations from the conclusions drawn from them, and techniques such as blind or double blind experiments , to minimize observational bias. Modern scientific instruments can extensively process "observations" before they are presented to
330-460: Is used to achieve several smooth color changes over a wide range of pH values. These commercial indicators (e.g., universal indicator and Hydrion papers ) are used when only rough knowledge of pH is necessary. For a titration, the difference between the true endpoint and the indicated endpoint is called the indicator error. Tabulated below are several common laboratory pH indicators. Indicators usually exhibit intermediate colors at pH values inside
363-479: The Henderson–Hasselbalch equation can be written as: The equations, derived from the acidity constant and basicity constant, states that when pH equals the p K a or p K b value of the indicator, both species are present in a 1:1 ratio. If pH is above the p K a or p K b value, the concentration of the conjugate base is greater than the concentration of the acid, and the color associated with
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#1732772581840396-415: The color difference between the two species should be as clear as possible, and the narrower the pH range of the color change the better. In some indicators, such as phenolphthalein , one of the species is colorless, whereas in other indicators, such as methyl red , both species confer a color. While pH indicators work efficiently at their designated pH range, they are usually destroyed at the extreme ends of
429-454: The conjugate base dominates. If pH is below the p K a or p K b value, the converse is true. Usually, the color change is not instantaneous at the p K a or p K b value, but a pH range exists where a mixture of colors is present. This pH range varies between indicators, but as a rule of thumb, it falls between the p K a or p K b value plus or minus one. This assumes that solutions retain their color as long as at least 10% of
462-450: The effect of supporting the researcher's conclusions. This is a form of bias that is difficult to quantify. Some scientific journals have begun to set detailed standards for what types of image processing are allowed in research results. Computerized instruments often keep a copy of the "raw data" from sensors before processing, which is the ultimate defense against processing bias, and similarly, scientific standards require preservation of
495-427: The human senses, and particularly with computerized instruments, there is sometimes a question as to where in the data processing chain "observing" ends and "drawing conclusions" begins. This has recently become an issue with digitally enhanced images published as experimental data in papers in scientific journals . The images are enhanced to bring out features that the researcher wants to emphasize, but this also has
528-415: The indicator bromocresol green . The observed spectrum (green) is the sum of the spectra of HA (gold) and of A (blue), weighted for the concentration of the two species. When a single indicator is used, this method is limited to measurements in the pH range p K a ± 1, but this range can be extended by using mixtures of two or more indicators. Because indicators have intense absorption spectra,
561-401: The indicator concentration is relatively low, and the indicator itself is assumed to have a negligible effect on pH. In acid-base titrations, an unfitting pH indicator may induce a color change in the indicator-containing solution before or after the actual equivalence point. As a result, different equivalence points for a solution can be concluded based on the pH indicator used. This is because
594-403: The indicator to be a simple acid, HA, which dissociates into H and A . The value of the acid dissociation constant , p K a , must be known. The molar absorbances , ε HA and ε A of the two species HA and A at wavelengths λ x and λ y must also have been determined by previous experiment. Assuming Beer's law to be obeyed, the measured absorbances A x and A y at
627-521: The listed transition range. For example, phenol red exhibits an orange color between pH 6.8 and pH 8.4. The transition range may shift slightly depending on the concentration of the indicator in the solution and on the temperature at which it is used. The figure on the right shows indicators with their operation range and color changes. An indicator may be used to obtain quite precise measurements of pH by measuring absorbance quantitatively at two or more wavelengths. The principle can be illustrated by taking
660-433: The mind makes up to fit the model; this is called reconstructive memory . How much attention the various perceived data are given depends on an internal value system, which judges how important it is to the individual. Thus two people can view the same event and come away with entirely different perceptions of it, even disagreeing about simple facts. This is why eyewitness testimony is notoriously unreliable. Several of
693-456: The more important ways observations can be affected by human psychology are given below. Human observations are biased toward confirming the observer's conscious and unconscious expectations and view of the world; we " see what we expect to see ". In psychology, this is called confirmation bias . Since the object of scientific research is the discovery of new phenomena, this bias can and has caused new discoveries to be overlooked; one example
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#1732772581840726-560: The observation is counted. Measurement reduces an observation to a number that can be recorded, and two observations which result in the same number are equal within the resolution of the process. Human senses are limited and subject to errors in perception, such as optical illusions . Scientific instruments were developed to aid human abilities of observation, such as weighing scales , clocks , telescopes , microscopes , thermometers , cameras , and tape recorders , and also translate into perceptible form events that are unobservable by
759-523: The original unenhanced "raw" versions of images used as research data. In Cosmology the origins of observation are related with the origins of evolutions in our cosmos. Process philosophy is the changing relationships of our senses , minds and experiences to ourselves . "Observe always that everything is the result of a change, and get used to thinking that there is nothing Nature loves so well as to change existing forms and to make new ones like them." PH indicator A pH indicator
792-424: The other species persists. For example, if the concentration of the conjugate base is 10 times greater than the concentration of the acid, their ratio is 10:1, and consequently the pH is p K a + 1 or p K b + 1. Conversely, if a 10-fold excess of the acid occurs with respect to the base, the ratio is 1:10 and the pH is p K a − 1 or p K b − 1. For optimal accuracy,
825-430: The pH scale due to undesired side reactions. pH indicators are frequently employed in titrations in analytical chemistry and biology to determine the extent of a chemical reaction . Because of the subjective choice (determination) of color, pH indicators are susceptible to imprecise readings. For applications requiring precise measurement of pH, a pH meter is frequently used. Sometimes, a blend of different indicators
858-411: The results of observation differ depending on factors that are not important in everyday observation. These are usually illustrated with apparent " paradoxes " in which an event appears different when observed from two different points of view, seeming to violate "common sense". The human senses do not function like a video camcorder , impartially recording all observations. Human perception occurs by
891-415: The same term [REDACTED] This disambiguation page lists articles associated with the title Observant . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Observant&oldid=1257057126 " Category : Disambiguation pages Hidden categories: Short description
924-409: The senses, such as indicator dyes , voltmeters , spectrometers , infrared cameras , oscilloscopes , interferometers , Geiger counters , and radio receivers . One problem encountered throughout scientific fields is that the observation may affect the process being observed, resulting in a different outcome than if the process was unobserved. This is called the observer effect . For example, it
957-527: The slightest color change of the indicator-containing solution suggests the equivalence point has been reached. Therefore, the most suitable pH indicator has an effective pH range, where the change in color is apparent, that encompasses the pH of the equivalence point of the solution being titrated. Many plants or plant parts contain chemicals from the naturally colored anthocyanin family of compounds. They are red in acidic solutions and blue in basic. Anthocyanins can be extracted with water or other solvents from
990-592: The solution to change depending on the pH. Indicators can also show change in other physical properties; for example, olfactory indicators show change in their odor . The pH value of a neutral solution is 7.0 at 25°C ( standard laboratory conditions ). Solutions with a pH value below 7.0 are considered acidic and solutions with pH value above 7.0 are basic. Since most naturally occurring organic compounds are weak electrolytes , such as carboxylic acids and amines , pH indicators find many applications in biology and analytical chemistry . Moreover, pH indicators form one of
1023-539: The three main types of indicator compounds used in chemical analysis. For the quantitative analysis of metal cations, the use of complexometric indicators is preferred, whereas the third compound class, the redox indicators , are used in redox titrations ( titrations involving one or more redox reactions as the basis of chemical analysis). In and of themselves, pH indicators are usually weak acids or weak bases. The general reaction scheme of acidic pH indicators in aqueous solutions can be formulated as: where, "HInd"
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1056-402: The two wavelengths are simply the sum of the absorbances due to each species. These are two equations in the two concentrations [HA] and [A ]. Once solved, the pH is obtained as If measurements are made at more than two wavelengths, the concentrations [HA] and [A ] can be calculated by linear least squares . In fact, a whole spectrum may be used for this purpose. The process is illustrated for
1089-406: Was developed to allow recording and comparison of observations made at different times and places, by different people. The measurement consists of using observation to compare the phenomenon being observed to a standard unit . The standard unit can be an artifact, process, or definition which can be duplicated or shared by all observers. In measurement, the number of standard units which is equal to
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