Darwin's flowers
Most people are familiar with the activities of Charles Darwin and his famous journey to South America... He made his most important discoveries in the Galapagos Islands, where each of the 20 islands had its own unique set of species, ideally adapted to live in those conditions. But few people know about Darwin's experiments after he returned to England. Some of them focused on orchids.
In the process of growing and studying several orchid species, he realized that complex orchid flowers are an adaptation that allows the flowers to attract insects, which then transfer pollen to neighboring plants. Each insect is specifically designed to pollinate one type of orchid. Take, for example, the Star of Bethlehem orchid (Angraecum sesquipedale), which stores its nectar at a depth of 30 centimeters. Darwin foresaw that there must necessarily be an insect that pollinates this type of orchid. Of course, in 1903, scientists discovered a species called the twilight butterfly, which has a long proboscis that can reach the nectar of this orchid species.
Darwin used the data he gathered about orchids and their insect pollinators to strengthen his theory of natural selection. He argued that cross-pollinated orchids are more viable than self-pollinated, as self-pollination reduces genetic diversity, which ultimately has a direct impact on the survival of the species. So, three years later, after he first described natural selection in On the Origin of Species, Darwin conducted several more experiments on flowers and strengthened his claims about the framework of evolution.
DNA decoding
James Watson and Francis Crick came very close to deciphering DNA, but their discoveries are heavily influenced by the work of Alfred Hershey and Martha Chase, who in 1952 conducted the famous to this day, an experiment that helped them determine how DNA molecules are related to heredity. Hershey and Chase worked with a type of virus known as a bacteriophage. This virus, consisting of a protein coat, surrounds the DNA strand, infects the bacterial cell, which programs it to produce new infected cells. Then the virus kills the cell and new viruses are born. Hershey and Chase knew about this, but, at the same time, they did not know which component - protein or DNA - was responsible for what was happening. They did not know this until they carried out their ingenious "blender" experiment, which led them to DNA ribonucleic acids.
After the Hershey and Chase experiment, many scientists such as Rosalind Franklin focused on studying DNA and its molecular structure. Franklin used a technique called X-ray diffraction to study DNA. It implies the "invasion" of X-rays into the fibers of the purified DNA. When the rays interact with the molecule, they "stray" from their original course and become diffracted. Then the diffracted rays form a picture of a unique molecule, ready for analysis. Famous photograph Franklin shows an X-shaped curve, which Watson and Crick labeled as the "signature of the DNA molecule." They were also able to determine the width of the spiral by looking at the image of Franklin.
First vaccination
Until the complete global eradication of smallpox at the end of the 20th century, the disease was a serious problem. In the 18th century, illness caused by the smallpox virus killed one in ten children born in Sweden and France. "Catching" the virus was the only way to "cure" it. This led to the fact that people themselves tried to catch the virus from purulent ulcers. Unfortunately, many of them died in a dangerous attempt to vaccinate themselves.
Edward Jenner, a British physician, began to study the virus and develop effective treatments. The genesis of his experiments was the observation that milkmaids living in his hometown were often infected with the vaccinia virus, a non-fatal disease similar to common smallpox. Milkmaids who contracted vaccinia seemed to be protected from smallpox infection, so in 1796 Jenner decided to test whether a person could develop immunity to common smallpox if infected with vaccinia virus. The boy Jenner decided to experiment with was James Phipps. Jenner made an incision in Phipps's arm and infected him with cowpox. After a while, the boy recovered. 48 days later, the doctor injected the smallpox virus into his body and found the boy immune.
Scientists now know that vaccinia and smallpox viruses are so similar that the immune system a person is not able to distinguish them.
Proof of the existence of an atomic nucleus
Physicist Ernest Rutherford had already won the Nobel Prize in 1908 for his radioactive work, while at that time he also began conducting experiments to reveal the structure of the atom. The experiments were based on his previous research, which showed that radioactivity consists of two types of rays - alpha and beta. Rutherford and Hans Geiger found that alpha rays are streams of positively charged particles. When he fired alpha particles onto the screen, they created a crisp and sharp image. But if there was a thin sheet of mica between the alpha radiation source and the screen, then the resulting image was blurry. It was clear that mica was scattering some alpha particles, but how and why this happened was not clear at that time.
In 1911, a physicist placed a thin sheet of gold foil between an alpha radiation source and a screen, 1-2 atoms thick. He also placed another screen in front of the alpha radiation source in order to understand which of the particles are deflected back. On the screen behind the foil, Rutherford observed a diffuse pattern similar to what he saw using a sheet of mica. What he saw on the screen in front of the foil surprised Rutherford a lot, as several alpha particles bounced right back. Rutherford concluded that the strong positive charge in the heart of the gold atoms sent the alpha particles back to their source. He called this strong positive charge a "nucleus", and stated that compared to overall size atom, its nucleus must be very small, otherwise a much larger number of particles would return back. Scientists today, like Rutherford, visualize atoms: small, positively charged nuclei surrounded by a large, mostly empty space in which several electrons live.
X-ray
We talked about X-ray diffraction from Franklin's research earlier, but he owes a lot of work to Dorothy Crowfoot Hodgkin, one of three women who won the Nobel Prize in Chemistry. In 1945, Hodgkin was considered one of the leading experts in the world practicing X-ray diffraction methods, so it is not surprising that it was she who, in the end, showed the structure of one of the most important today chemical substances in medicine - penicillin. Alexander Fleming discovered the bacteria-killing substance back in 1928, but it took scientists some more time to purify the substance in order to develop effective treatment... Thus, with the help of penicillin atoms, Hodgkin was able to create semi-synthetic derivatives of penicillin, which turned out to be a revolution in the fight against infections.
Hodgkin's research became known as X-ray crystallography. For the first time, chemists crystallized the compounds they wanted to analyze. It was a challenge. After testing penicillin crystals by two different companies, Hodgkin sent X-rays through the crystals and allowed radiation to "enter the object under study." When the X-rays interacted with the electrons of the object under study, the rays became slightly diffracted. This resulted in a clear dot pattern on the film. After analyzing the position and brightness of these points and performing many calculations, Hodgkin determined exactly how the atoms are located in the penicillin molecule.
Several years later, she used the same technology to identify the structure of vitamin B12. She received the Nobel Prize in Chemistry in 1964, an honor no other woman has ever won.
The emergence of life
In 1929, biochemists John Haldane and Alexander Oparin independently suggested that there was no free oxygen in the early Earth's atmosphere. Under those harsh conditions, they speculated, organic compounds could be formed from simple molecules, receiving a serious charge of energy, be it ultraviolet radiation or bright light. Haldane also added that the oceans were likely the first sources of these organic compounds.
American chemists Harold Urey and Stanley Miller decided to test the hypotheses of Oparin and Haldane in 1953. They managed to recreate Earth's early atmosphere through meticulous work on a controlled, closed system. A flask with heated water played the role of the ocean. After the water vapor rose and collected in another container, Yuri and Miller added hydrogen, methane and ammonia in order to simulate an oxygen-free atmosphere. Sparks then formed in the bulb, representing light in a mixture of gases. Finally, the condenser cooled the gases in the liquid, which they then took for analysis.
A week later, Yuri and Miller got amazing results: organic compounds were abundant in the chilled liquid. In particular, Miller discovered several amino acids, including glycine, alanine, and glutamic acid. Amino acids are the building blocks of proteins, which are themselves key components of both cellular structures and cellular enzymes responsible for the functioning of important chemical reactions. Uri and Miller came to the conclusion that organic molecules could well survive in an oxygen-free environment, which, in turn, did not keep waiting for the appearance of the simplest organisms.
Creation of light
When the light appeared in the 19th century, it remained a mystery that inspired many fascinating experiments. For example, Thomas Young's "double-slit experiment", which showed how light waves but not particles. But then they did not yet know how fast light travels.
In 1878, physicist A.A. Michelson conducted an experiment in order to calculate the speed of light and prove that it is a finite, measurable quantity. Here's what he did:
1. First, he placed two mirrors far apart on opposite sides of the dam near the campus, arranging them so that the incident light reflected from one mirror and returned back. He measured the distance between the mirrors and found that it was 605.4029 meters.
3. Using lenses, he focused a beam of light on a stationary mirror. When a beam of light touched a stationary mirror, it bounced and reflected in a rotating mirror, near which Michelson placed a special screen. Due to the fact that the second mirror was rotating, the trajectory of the return of the light beam changed slightly. When Michelson measured these deviations, he got a figure of 133 mm.
4. Using the data obtained, he was able to measure the speed of light equal to 186380 miles per second (299,949,530 kilometers). The permissible value for the speed of light today is 299,792,458 km per second. Michelson's measurements showed surprisingly accurate results. Moreover, scientists now have more accurate ideas about light and the foundations on which the theory is built. quantum mechanics and the theory of relativity.
Discovery of radiation
1897 was a very important year for Marie Curie. Her first child was born, and just a few weeks after his birth, she went to look for a topic for her doctoral dissertation. Eventually, she decided to study the "uranium rays" first described by Henri Becquerel. Becquerel discovered these rays by accident when he left uranium salts, wrapped them in an opaque material along with photographic plates in a dark room, and when he returned, he found that the photographic plates were completely overexposed. Marie Curie chose these mysterious rays to study in order to reveal other elements acting in a similar way.
Already at an early stage of her study, Curie realized that thorium produces the same rays as uranium. She began to label these unique elements as "radioactive" and quickly realized that the strength of radiation generated by uranium and thorium depends on the amount of thorium and uranium. In the end, she will be able to prove that the rays are the properties of the atoms of a radioactive element. It was a revolutionary discovery in itself, but Curie stopped it.
She discovered that pitchblende (uraninite) is more radioactive than uranium, which prompted her to think that there must be an element unknown to her in natural minerals. Her husband Pierre joined the research, and they systematically reduced pitchblende amounts until they discovered a new isolated element. They named it polonium, after the motherland of Maria Poland. Shortly thereafter, they discovered another radioactive element, which they named radium, from the Latin for "ray". Curie has won two Nobel Prizes for her work.
Dog days
Did you know that Ivan Pavlov, a Russian physiologist and chemist, and the author of the experiment on the development of salivation in dogs and inoculating them with a conditioned reflex, was not at all interested in psychology or behavior? He was interested in the topics of digestion and circulation. In fact, he was studying the digestive system of dogs when he discovered what we know today as "conditioned reflexes."
In particular, he tried to understand the relationship between salivation and the work of the stomach. Shortly before this, Pavlov had already noted that the stomach does not begin to digest food without salivation, which occurs in the first place. In other words, reflexes in the vegetative nervous system these two processes are closely related to each other. Next, Pavlov decided to find out if external stimuli could affect digestion. the same way... To check this, he began to turn on and off the lights while the dog was eating, ticking with a metronome, and made the buzzer sound audible. In the absence of these stimuli, dogs salivated only when they saw and ate food. But after a while, they began to salivate when stimulated by sound and light, even if they were not given food at that time. Pavlov also found that this type of conditioned reflex dies if the stimulus is used too often. For example, if a dog hears a sound signal often, but does not receive food, then after a while, it stops responding to the sound by salivating.
Pavlov published his results in 1903. A year later, he received the Nobel Prize in Medicine, not for his work on conditioned reflexes, but "in recognition of his work on the physiology of digestion, through which knowledge of vital aspects was transformed and expanded."
Stanley Milgram's experiments in the 1960s are still regarded as some of the most famous and controversial scientific experiments to this day. Milgram wanted to find out how far an ordinary person could go in inflicting pain on another person under the pressure of authority. Here's what he did:
1. Milgram recruited volunteers, ordinary people, who were ordered to inflict some pain on other volunteer actors. The experimenter played the role of an authority who was constantly present in the room during the research.
2. Before the beginning of each test, the authority demonstrated to unsuspecting volunteers how to use a shock - an apparatus that could hit a person with a discharge of 15-450 volts ( elevated level danger).
3. The scientist further noted that they should test how a shock shock can improve the memorization of words through associations. He instructed volunteers to "reward" volunteer actors with shock shocks for incorrect answers during the experiment. The more wrong answers there were, the higher the voltage level on the apparatus. Moreover, it is worth noting that the device was made at the highest level: the voltage corresponding to it was written above each switch, from "weak blow" to "hard-to-bear blow", the device was equipped with many panels with dial voltmeters. That is, the subjects did not have the opportunity to doubt the authenticity of the experiment, and the study was designed in such a way that for each correct answer there were three wrong ones and the authority told the volunteer what kind of "blow" to punish the "incapable student".
4. "Students" screamed when they received shock blows. After the force of the blow exceeded 150 volts, they demanded release. At the same time, the authority urged the volunteers to continue the experiment, not paying attention to the demands of the "students".
5. Some participants in the experiment wished to leave after reaching the 150 volt penalty, but most continued until they reached the maximum shock level of 450 volts.
At the end of the experiments, many spoke out about the unethicality of this study, but the results were impressive. Milgram proved that ordinary people can hurt to an innocent person simply because they received such a command from an authority figure.
Guys, we put our soul into the site. Thank you for
that you discover this beauty. Thanks for the inspiration and the goosebumps.
Join us at Facebook and In contact with
There are very simple experiences that children remember for a lifetime. The guys may not fully understand why this is all happening, but when time passes and they find themselves in a physics or chemistry lesson, a very clear example will surely pop up in their memory.
site collected 7 interesting experiments that will be remembered by children. Everything you need for these experiments is at your fingertips.
Refractory ball
It will take: 2 balls, candle, matches, water.
An experience: Inflate the balloon and hold it over a lighted candle to demonstrate to the children that the balloon will burst from the fire. Then pour plain tap water into the second ball, tie it and bring it back to the candle. It turns out that with water the ball can easily withstand the flame of a candle.
Explanation: The water in the ball absorbs the heat generated by the candle. Therefore, the ball itself will not burn and, therefore, will not burst.
Pencils
You will need: plastic bag, pencils, water.
An experience: Pour half of the water into a plastic bag. With a pencil we pierce the bag through in the place where it is filled with water.
Explanation: If you pierce a plastic bag and then pour water into it, it will pour out through the holes. But if you first fill the bag with water halfway and then pierce it with a sharp object so that the object remains stuck in the bag, then almost no water will flow out through these holes. This is due to the fact that when polyethylene breaks down, its molecules are attracted closer to each other. In our case, the polyethylene is tightened around the pencils.
Unbreakable ball
You will need: balloon, a wooden skewer and some dishwashing liquid.
An experience: Lubricate the top and bottom with the product and pierce the ball starting from the bottom.
Explanation: The secret to this trick is simple. In order to preserve the ball, you need to pierce it at the points of least tension, which are located at the bottom and top of the ball.
Cauliflower
It will take: 4 glasses of water, food coloring, cabbage leaves or white flowers.
An experience: Add food coloring of any color to each glass and place one leaf or flower in the water. Leave them overnight. In the morning you will see that they are colored in different colors.
Explanation: Plants absorb water and thus nourish their flowers and leaves. This is due to the capillary effect, in which the water itself tends to fill the thin tubes inside the plants. This is how flowers, grass and large trees eat. Sucking in the colored water, they change their color.
Floating egg
It will take: 2 eggs, 2 glasses of water, salt.
An experience: Place the egg gently in a glass of plain clean water. As expected, it will sink to the bottom (if not, the egg might be rotten and shouldn't be returned to the refrigerator). Pour warm water into the second glass and stir 4-5 tablespoons of salt in it. For the purity of the experiment, you can wait until the water cools down. Then dip the second egg into the water. It will float near the surface.
Explanation: It's all about density. The average density of the egg is much higher than that of plain water, so the egg sinks downward. And the density of the brine is higher, and therefore the egg rises up.
Crystal lollipops
It will take: 2 glasses of water, 5 glasses of sugar, wooden sticks for mini-kebabs, thick paper, transparent glasses, a saucepan, food coloring.
An experience: In a quarter glass of water, boil the sugar syrup with a couple tablespoons of sugar. Pour some sugar onto the paper. Then you need to dip the stick in syrup and collect the saccharins with it. Next, distribute them evenly on a stick.
Leave the sticks to dry overnight. In the morning, dissolve 5 glasses of sugar in 2 glasses of water over the fire. You can leave the syrup to cool for 15 minutes, but it should not cool much, otherwise the crystals will not grow. Then pour it into jars and add different food colors. Dip the prepared sticks into a jar of syrup so that they do not touch the walls and bottom of the jar, a clothespin will help with this.
Explanation: As the water cools, the solubility of sugar decreases, and it begins to precipitate and settle on the walls of the vessel and on your stick with a seed of sugar grains.
A lit match
Will need: Matches, flashlight.
An experience: Light a match and keep 10-15 centimeters away from the wall. Shine a flashlight on the match, and you will see that only your hand and the match itself are reflected on the wall. It would seem obvious, but I never thought about it.
Explanation: Fire does not cast shadows as it does not interfere with the passage of light through itself.
psychology test subject
Man and his personality traits have been the object of interest and study of the great minds of mankind for more than one century. And from the very beginning of the development of psychological science to the present day, people have been able to develop and significantly improve their skills in this difficult but exciting business. Therefore, now, to obtain reliable data in the study of the characteristics of the human psyche and his personality, people use big amount the most different ways and research methods in psychology. And one of the methods that have received the most popularity and have proven themselves from the most practical point of view is a psychological experiment.
An experiment in psychology is a certain experience that is carried out under special conditions in order to obtain psychological data through the intervention of the researcher in the process of the subject's activity. Both a specialist scientist and a simple layman can act as a researcher in the process of an experiment.
The main characteristics and features of the experiment are:
- · The ability to change any variable and create new conditions for identifying new patterns;
- · Ability to choose a starting point;
- · Possibility of repeated holding;
- · The ability to include in the experiment other methods of psychological research: test, survey, observation and others.
There are many views on the differentiation of experimental techniques and a significant number of terms designating them. If we summarize the results in this area, then the totality of the main varieties of the experiment can be represented in the following form:
I. According to the validity and completeness of the procedure
- 1. Real (specific). A real (specific) experiment is an experiment carried out in reality under specific experimental conditions. It is real research that provides factual material used for both practical and theoretical purposes. Experimental results are valid for specific conditions and populations. Their transfer to broader conditions is probabilistic.
- 2. Mental (abstract): A mental experiment is an imaginary experience that is not actually possible. Sometimes this category also includes mental manipulations regarding the organization and conduct of a planned real experiment in the future. But such a preliminary "replaying" of real experience in the mind is in fact its obligatory attribute, realized at the preparatory stages of the study (problem statement, hypothesis, planning).
- a) perfect;
- b) endless;
- c) flawless.
An ideal experiment is one in which the dependent variable is not influenced by any other than one independent variable. In reality, it is impossible to exclude the additional influences of a multitude of attendant factors. Therefore, a perfect experiment is not really feasible. In practice, the approximation of a real experience to an ideal one is realized by controlling additional variables described in the description of the experimental procedure.
An endless experiment is an experiment that covers all possible experimental situations for the entire studied population (general population). In reality, many such situations are limitless due to the huge, and often unknown, size of the general population and the countless number of factors acting on the subject. Taking into account all this endless set of situations can be performed only in the imagination of the researcher. Due to its infinity (in variety and in time), such an experiment was called infinite. The practical meaninglessness of an endless experiment is in contradiction with one of the main ideas of empirical research - the transfer of the results obtained on a limited sample to the entire general population... It is needed only as a theoretical model.
Flawless is an experiment that combines the features of both ideal and endless experimentation. As a standard of an exhaustive experiment, it makes it possible to assess the completeness and, accordingly, the shortcomings of a specific real experience.
II. By the purpose of the experiment
1. Research.
A research experiment is an experience aimed at gaining new knowledge about an object and a subject of study. It is with this type of experiments that the concept of "scientific experiment" is usually associated, since the main goal of science is the knowledge of the unknown. While the other two types of goal criterion experiment are predominantly of an applied nature, the research experiment performs mainly a search function.
2. Diagnostic (survey).
A diagnostic (survey) experiment is a task-experience performed by a subject in order to detect or measure some of his qualities. These experiments do not provide new knowledge about the subject of research (personality quality). This is actually testing.
3. Demonstration.
A demonstration experiment is an illustrative experience that accompanies educational or recreational activities. The immediate goal of such experiments is to familiarize the audience with either the appropriate experimental method, or with the effect obtained in the experiment. Most widespread demonstration experiments were found in educational practice. With their help, students master research and diagnostic techniques. An additional goal is often set - to interest students in the relevant field of knowledge.
III. By research level
1. Preliminary (reconnaissance)
A preliminary (reconnaissance) experiment is an experiment carried out to clarify the problem and provide an adequate orientation in it. With its help, little-known situations are probed, hypotheses are clarified, questions for further research are identified and formulated. Research of this reconnaissance nature is often referred to as aerobatic. On the basis of the data obtained in preliminary experiments, the questions about the necessity and possibilities of further research in this area and the organization of the main experiments are resolved.
2. Main
The main experiment is a full-scale empirical study carried out with the aim of obtaining new scientific data on a problem of interest to the experimenter. The resulting result is used for both theoretical and applied purposes. The main experiment can be preceded by preliminary ones of both reconnaissance and introductory nature.
3. Control.
A control experiment is an experiment, the results of which are compared with the results of the main experiment. The need for control can arise for a variety of reasons. For example: 1) errors were found in conducting basic experiments; 2) doubts about the accuracy of the procedure; 3) doubts about the adequacy of the procedure to the hypothesis; 4) the emergence of new scientific data that contradict those obtained earlier; 5) striving for additional evidence of the validity of the hypothesis adopted in the main experiment and its transformation into a theory; 6) the desire to refute existing hypotheses or theories. It is clear that the control experiments should not be inferior to the main ones in terms of the degree of accuracy and reliability.
IV. By the type of exposure to the subject
1. Internal.
An internal experiment is a real experiment, where mental phenomena are caused or changed directly by the volitional effort of the subject, and not by influence from the external world. Experimentation is carried out in the subjective space of a person, where he plays the role of both the experimenter and the subject. Internal influence always includes an independent variable, and ideally only it should be limited. This brings the inner experiment closer to the mental ideal.
2. External.
An external experiment is a usual experimental way of studying mental phenomena, when their appearance or change is achieved due to external influences on the subject's sense organs.
V. According to the degree of intervention of the experimenters, the life of the subject (according to the type of experimental situation)
A. Classical grouping
1. Laboratory (artificial).
A laboratory (artificial) experiment is an experiment staged under artificially created conditions that make it possible to strictly dose stimulation (independent variables) and control other effects on the subject (additional variables), as well as accurately record his responses, including dependent variables. The subject is aware of his role in the experiment, but his general design is usually not known to him.
2. Natural (field).
Natural (field) experiment - an experiment carried out in the usual conditions for the subject with a minimum of interference in his life on the part of the experimenter. The presentation of the independent variable is, as it were, “woven” in a natural way into the usual course of his activity. Depending on the type of activity performed and the corresponding situation, the types of natural experiment are also distinguished: in conditions of communication, labor, play, educational, military activities, in conditions of everyday life and leisure. Specific view of this type experiments - an investigative experiment in which the artificiality of the procedure is combined with the naturalness of the conditions for illegal actions.
3. Formative.
A formative experiment is a method of actively influencing the subject, contributing to his mental development and personal growth. The main areas of application of this method are pedagogy, developmental (primarily children's) and educational psychology. The experimenter's active influence consists mainly in the creation of special conditions and situations, which, firstly, initiate the emergence of certain mental functions and, secondly, they allow them to purposefully change and shape them. The first is typical for both laboratory and natural experiments. The second is the specificity of the considered form of experiment. The formation of the psyche and personality traits is a lengthy process. Therefore, the formative experiment is usually carried out for a long time. And in this respect it can be classified as a longitudinal study.
B. Extraordinary grouping:
1. An experiment that duplicates reality.
Experiments that duplicate reality are experiments that simulate specific situations in real life, the results of which have a low level of generalization. Their findings apply to specific people in the context of a specific activity, therefore they are also called experiments of complete correspondence. These experiments pursue purely practical goals. This type of experiment is close to the natural type according to the classical grouping.
2. Experiment to improve reality.
Reality-enhancing experiments are experiments in which only some of the variables to be studied are changed. The rest of the variables are stable. This type is similar to a laboratory experiment according to the generally accepted classification.
Vi. If possible, the experimenter's influence on the independent variable
1. A provoked experiment.
A provoked experiment is an experiment in which the experimenter himself acts on the independent variable. NP changes can be both quantitative and qualitative. And then the results observed by the experimenter (in the form of the subject's reactions) are, as it were, provoked by him. Obviously, the overwhelming majority experimental research refers specifically to this species. P. Fress not without reason calls this type of experiment "classical".
2. Experiment referenced.
The experiment referred to is an experiment in which a change in the independent variable is performed without the intervention of the experimenter. This includes personality changes, brain damage, cultural differences, etc. According to P. Fress, these cases are very valuable, “since the experimenter cannot introduce variables, the action of which would be slow (the upbringing system), and has no right to experiment on a person if his experiment can cause serious and irreversible physiological or psychological disturbances. ". There may be times when an experiment on one variable is provoked, and on others it is referenced.
Vii. By the number of independent variables
1. One-factor (two-dimensional).
A univariate (two-dimensional) experiment is an experiment with one independent and one dependent variable. Since there is only one factor influencing the respondent's answers, the experience is called one-factor or one-level. And since there are two measurable quantities - NP and ZP, the experiment is called two-dimensional or bivalent. Allocation of only two variables allows you to study a mental phenomenon in a "pure" form. The implementation of such a variant of the study is carried out using the procedures described above for controlling additional variables and presenting an independent variable.
2. Multifactorial (multidimensional).
A multivariate (multivariate) experiment is an experiment with several independent and usually one dependent variable. The presence of several dependent variables is not excluded, but this case is still extremely rare in psychological research. Although, apparently, the future belongs to him, since real mental phenomena always represent the most complex system many interacting factors. The term "poorly organized systems", widespread in science, is applicable to them, which just emphasizes the multiplicity of the determination of their manifestation.
VIII. By the number of subjects
1. Individual.
An individual experiment is an experiment with one subject.
2. Group.
Experience with several subjects at the same time. Their mutual influences can be both significant and insignificant, can be taken into account by the experimenter or not taken into account. If the mutual influences of the subjects on each other are due not only to co-presence, but also to joint activity, then it is possible to speak of a collective experiment.
IX. By the method of identifying relationships between variables (by the procedure for varying the experimental situation)
1. Intra-procedural (inside).
An intraprocedural experiment (Latin intra - inside) is an experiment in which all experimental situations (and, in fact, all values of the independent variable) are presented to the same contingent of subjects. If the subject is alone, i.e. an individual experience is carried out, then one speaks of an intra-individual experiment. Comparison of the responses of this subject obtained in different situations(for different values of NP), and makes it possible to identify dependencies between variables. This option is especially convenient for quantitative changes in NP to determine functional dependencies.
2. Interprocedural (between).
Interprocedural experiment (Latin inter - between) - an experiment in which different contingents of subjects are presented with the same experimental situations. Work with each individual contingent is carried out either in different places, either in different time, or by different experimenters, but using identical programs. The main purpose of such experiments is to clarify individual or intergroup differences. Naturally, the former are revealed in a series of individual experiments, and the latter - in group ones. And then, in the first case, they talk about an interindividual experiment, in the second - about an intergroup, or more often an intergroup experiment.
3. Cross-procedural (intersection).
A cross-procedural experiment is an experiment in which different contingents of subjects are presented with different situations. If the subjects work alone, then we are talking about a cross-individual experiment. If a certain group of subjects corresponds to each situation, then this is a cross-group experiment, which is sometimes called an inter-group experiment, which is a terminological inaccuracy. Intergroup is synonymous with intergroup, not cross-group experimentation. This inaccuracy is due either to inadequate translation of foreign sources, or due to a careless attitude to terminology.
X. By type of change in the independent variable
1. Quantitative.
A quantitative experiment is an experiment in which the independent variable can decrease or increase. A number of its possible values represent a continuum, i.e. continuous sequence of values. These values, as a rule, can be expressed numerically, since the NP has units of measurement. Depending on the nature of the NP, its quantitative representation can be carried out in different ways. For example, time interval (duration), dosage, weight, concentration, number of elements. These are physical indicators. The quantitative expression of NP can be realized through psychological indicators: both psychophysical and psychometric.
2. High quality.
A qualitative experiment is one in which the independent variable has no quantitative variation. Its meanings appear only as various qualitative modifications. Examples: sex differences in populations, modal differences in signals, etc. The limiting case of a qualitative representation of an NP is its presence or absence. For example: presence (absence) of interference.
There are many views on the differentiation of experimental techniques and a significant number of terms designating them.
If we summarize the results in this area, then the totality of the main varieties of the experiment can be represented in the following form:
I. According to the validity and completeness of the procedure:
1. Real (specific).
2. Mental (abstract):
a) perfect;
b) endless;
c) flawless.
II. For the purpose of the experiment:
1. Research.
2. Diagnostic (survey).
3. Demonstration.
III. By research level:
1. Preliminary (reconnaissance).
2. Basic;
3. Control.
IV. By the type of exposure to the subject:
1. Internal.
2. External.
V. According to the degree of intervention of the experimenters, the life of the subject (according to the type of experimental situation):
A. Classic grouping:
1. Laboratory (artificial).
2. Natural (field).
3. Formative.
B. Extraordinary grouping:
1. An experiment that duplicates reality.
2. Experiment to improve reality.
Vi. If possible, the experimenter's influence on the independent variable:
1. A provoked experiment.
2. Experiment referenced.
Vii. By the number of independent variables:
1. One-factor (two-dimensional).
2. Multifactorial (multidimensional).
VIII. By the number of subjects:
1. Individual.
2. Group.
IX. According to the method of identifying relationships between variables (according to the procedure for varying the experimental situation):
1. Intra-procedural (inside).
2. Interprocedural (between).
3. Cross-procedural (intersection).
X. By type of change in the independent variable:
1. Quantitative.
2. High quality.
Real (specific) experiment is an experiment carried out in reality under specific experimental conditions. It is real research that provides factual material used for both practical and theoretical purposes. Experimental results are valid for specific conditions and populations. Their transfer to broader conditions is probabilistic.
Thought experiment- an imaginary experience that is impossible in reality. Sometimes this category also includes mental manipulations regarding the organization and conduct of a planned real experiment in the future. But such a preliminary "replaying" of real experience in the mind is in fact its obligatory attribute, realized at the preparatory stages of the study (problem statement, hypothesis, planning).
Discussions about the "empiricality" or "theoreticalness" of a thought experiment seem to us endless and hopeless, since the border between the corresponding types of knowledge and research is rather arbitrary. Proponents of the theoretical nature of a thought experiment usually refer to the fact that its application is associated mainly with the advancement and development of a hypothesis, and not with the stage of collecting data about the object under study. This is indeed the case. Thought experiment is used mainly for the purpose of a clearer understanding of the hypothesis put forward and for comparison with real experience as a reference.
However, it contains all the signs and elements of an empirical real experiment, but only in a conditional and ideal form:
There is a direct intrusion of the experimenter (albeit imaginary) into the life of the object (albeit presented in the form of an ideal model);
The strictest (albeit conditionally) control and fixation of all variables and answers is carried out;
Any number of repetitions of the experiment is allowed;
An unambiguous understanding of the results of the experiment is achieved, etc.
Ideal, endless, and flawless experiments are the main types of thought experiment.
Formative experiment - it is a method of active influence on the subject, contributing to his mental development and personal growth. The main areas of application of this method are pedagogy, developmental (primarily child) and educational psychology. The experimenter's active influence consists mainly in creating special conditions and situations that, firstly, initiate the appearance of certain mental functions and, secondly, allow them to purposefully change and shape them. The first is typical for both laboratory and natural experiments. The second is the specificity of the considered form of experiment. The formation of the psyche and personality traits is a lengthy process. Therefore, the formative experiment is usually carried out for a long time. And in this respect it can be classified as a longitudinal study.
A fundamentally similar effect can lead to negative consequences for the subject or society. Therefore, the qualifications and good intentions of the experimenter are extremely important. Research of this kind should not harm the physical, mental and moral health of people.
To a certain extent, a formative experiment occupies an intermediate position between laboratory and natural. The artificiality of creating special conditions brings it closer to the laboratory one, and the natural character of these very conditions brings it closer to the field one. The predominant use of the formative experiment in pedagogy led to the understanding of this method as one of the forms psychological and pedagogical experiment. Another form of psychological and pedagogical experiment is then considered an experiment ascertaining, allowing only to register a particular phenomenon or the level of its development in children. It seems, nevertheless, that the hierarchy of concepts should be different, if only because the concept of "formation" is broader than the pedagogical concepts of "training" and "education". The formation procedure can refer not only to the animate world, but also to the inanimate world. As for the formation of mental qualities, it is applicable not only to humans, but also to animals. Actually, learning of animals is based on this.
BF Lomov considers the formative experiment outside the pedagogical context when he analyzes the problem of the experimenter's influence on the subject's answers. And the psychological and pedagogical experiment then acts as a special case of the formative one. It is possible to cite other examples of the concretization of a formative experiment that perform not only pedagogical functions. So, experimental genetic method research mental development, proposed by LS Vygotsky, is aimed at studying the formation of various mental processes. The development of the experimental genetic method as a research, diagnostic and teaching technique is the method of systematic step-by-step formation of mental actions, proposed by P. Ya. Galperin.
Widespread learning experiment, the main task of which is to vary the content and forms of a person's educational activity in order to determine the influence of these changes on the pace and characteristics of a person's mental (primarily mental) development. As you can see, in this version, the research component is not inferior to the teaching one. And the training itself can be carried out not only in pedagogical terms, but also professionally.
A great contribution to the development, improvement and application of these methods was made by domestic psychologists L.A. Venger, P. Ya.Gal'perin, V.V.Davydov, A.V. A. Lyublinskaya, D. B. Elkonin.
The essence of the formative experiment in the context of child psychology was very accurately formulated by L. I. Bozhovich: it is a method of "studying the personality of a child in the process of his active and purposeful upbringing."
In addition to teaching and psychological-pedagogical, many other terms are used as synonyms for a formative experiment: transforming, creative, constructive, upbringing, genetic modeling experiment, a method of active formation of the psyche and even psychotherapeutic experiment.
The classification proposed by R. Gottsdanker is close to the just considered division into laboratory and natural types of experiment. According to approximately the same criterion (the degree of intervention of the experimenter in the subject's activity), he distinguishes two types of experiment: duplicating and improving the real world.
Experiments that duplicate reality- these are experiments that simulate specific situations in real life, the results of which have a low level of generalization. Their conclusions are applicable to specific people in the context of specific activities, therefore they are also called full matching experiments. These experiments pursue purely practical goals. This type of experiment is close to the natural type according to the classical grouping.
Experiments to improve reality- these are experiments in which only some of the variables to be studied are subject to change. The rest of the variables are stable. This type is similar to a laboratory experiment according to the generally accepted classification.
The above classification of R. Gottsdanker has recently been qualified by some researchers as “contrived and archaic”, since “in the developed sciences, they tend to avoid a“ direct circuit ”between the experimental result and reality, since it is clear that the experiment is based on the requirements of a testable theory, and not from requirements of reality compliance ”. This criticism stems from the understanding that external validity is psychological experiment as the ultimate adequacy of the experimental situation life circumstances, firstly, it is fundamentally unattainable and, secondly, it is relevant only in applied, but not in basic research... But then all these critical arrows with the same success should be directed at dividing the experiment into "non-life" laboratory and "close to life" natural.
Claude Bernard proposed to distinguish between two types of experiment: provoked and referred to. Paul Fress considered this division to be very useful in psychology.
A provoked experiment is an experiment in which the experimenter himself acts on the independent variable. NP changes can be both quantitative and qualitative. And then the results observed by the experimenter (in the form of the subject's reactions) are, as it were, provoked by him. Obviously, the overwhelming majority of experimental studies refer to this particular species. P. Fress not without reason calls this type of experiment "classical".
The experiment referred to is an experiment in which a change in the independent variable is performed without the intervention of the experimenter. These include personality changes, brain damage, cultural differences, etc. According to P. Fress, these cases are very valuable, “since the experimenter cannot introduce variables whose action would be slow (the upbringing system), and has no right to experiment on a person if his experiment can cause serious and irreversible physiological or psychological disorders. " There may be times when an experiment on one variable is provoked, and on others it is referenced.
One-way (two-dimensional) experiment is an experiment with one independent and one dependent variable. Since there is only one factor influencing the respondent's answers, experience is called univariate or sibling. And since there are two measurable quantities - NP and ZP, insofar as the experiment is called two-dimensional or bivalent. Allocation of only two variables allows you to study a mental phenomenon in a "pure" form.
The implementation of such a variant of the study is carried out using the procedures described above for controlling additional variables and presenting an independent variable. The bulk of the experimental material in psychology was obtained using univariate experiments. Recall that they are still the main tool for studying mental phenomena at the functional level, that is, at the level that allows you to establish functional relationships between variables. It is clear that a one-factor experiment is being implemented under laboratory conditions.
Multivariate (multivariate) experiment is an experiment with several independent and usually one dependent variable. The presence of several dependent variables is not excluded, but this case is still extremely rare in psychological research. Although, apparently, the future belongs to him, since real mental phenomena always represent the most complex system of many interacting factors. The name "poorly organized systems", which is widespread in science, is applicable to them, which just emphasizes the multiplicity of the determination of their manifestation.
Multifactorial experimentation has developed along two main lines. The first is connected with the already mentioned English scientist R. Fisher, the developer of the analysis of variance. This approach is based on the ideas of statistical laws. The second direction is associated with the ideas of cybernetics. Apparently, this circumstance is due to the designation of a multifactorial experiment by the term Burnetic experiment "... By now, perhaps, both directions have merged into one and are difficult to distinguish.
In psychology, a multifactorial experiment is used in situations where it is impossible to exclude or even out the influence of additional variables, or when, according to the research task, it is required to find out the joint effect of several independent variables on the subject. Naturally, this system includes factors that can be taken into account (and even better, measured).
Thus, what cannot be achieved by direct manipulation of variables in a univariate experiment can be achieved by statistical analysis of many variables in a multivariate experiment. An analysis of variance (and its modifications) is the usual way of doing this. Rationalization of the multivariate experiment procedure is achieved using the experiment planning process outlined above. The main advantage of the method is the approximation of the experimental situation to the real conditions of the subject's life.
The risk of distortion or "contamination" of the results by side effects, which is inherent in the one-factor option, is significantly reduced. Here, instead of trying to eliminate contaminating effects (mutual influence), they are studied. "The analysis of the relationships between the studied characteristics allows us to reveal the largest number of hidden structural factors, on which the observed variations of the measured variables depend."
Currently psychological science believes that the observed initial signs of an individual's behavior are only superficial indicators that indirectly reflect personality traits hidden from direct observation, the knowledge of which makes it possible to simply and clearly describe individual behavior. It is believed that there are fewer of these hidden traits (actually determining the behavior of factors) than superficial ones. Descriptions through factors as a system of interconnected external signs are much more economical than descriptions through these outward signs... Thus, a multifactorial experiment helps to identify the true, essential determinants of human behavior. Obviously, multifactorial experimentation can be successfully applied in areas where behavior is studied in vivo.
Nevertheless, the multivariate experiment is still only gaining an equal position with the univariate one. The main reasons for this situation are considered: 1) the difficulty (or sometimes inability) to break out of the usual stereotypes about the rules of conducting research and 2) the small number of publications on the theory of multidimensional research.
Synonyms for a multivariate experiment: multilevel; multidimensional, multivalent experiment
An individual experiment is an experiment with one subject.
Group experiment - an experiment with several subjects at the same time. Their mutual influences can be both significant and insignificant, can be taken into account by the experimenter or not taken into account. If the mutual influences of the subjects on each other are due not only to co-presence, but also to joint activity, then it is possible to talk about collective experiment.
Intra-procedural experiment ( lat. intra - inside) is an experiment in which all experimental situations (and in essence, all values of the independent variable) are presented to the same contingent of subjects. If the subject is alone, that is, an individual experiment is carried out, then they talk about intra-individual experiment. Comparison of the answers of this subject, obtained in different situations (for different values of NP), and makes it possible to identify dependencies between the variables. This option is especially convenient for quantitative changes in NP to determine functional dependencies.
The implementation of the considered procedure is also possible in a group version. Such experiments are usually devoted to the study interpersonal relationships in various social groups. Then the experiments can be called shtragroupovym. For the sake of fairness, it must be said that in the literature known to us, the term "intragroup experiment" is absent. It is supposed for the time being to be regarded as a logical addition to the intraindividual. The main purpose of such experiments is to identify general patterns for a particular population.
Interprocedural experiment ( lat. inter - between) - an experiment in which different contingents of subjects are presented with the same experimental situations. Work with each individual contingent is carried out either in different places, or at different times, or by different experimenters, but according to identical programs. The main purpose of such experiments is to clarify individual or intergroup differences. Naturally, the former are revealed in a series of individual experiments, and the latter - in group ones. And then in the first case they talk about interindividual experiment, secondly - about intergroup, or more often intergroup experiment.
Cross procedural experiment ( English cross - to cross) is an experiment in which different contingents of subjects are presented with different situations. If the subjects work alone, then we are talking about cross-individual experiment. If a certain group of subjects corresponds to each situation, then this is - cross-group experiment, which is sometimes called intergroup, which is a terminological inaccuracy. Intergroup is synonymous with intergroup, not cross-group experimentation. This inaccuracy is due either to inadequate translation of foreign sources, or due to a careless attitude to terminology.
This type of experiment is used with equal success both to study general psychological and differential psychological factors and patterns. Cross-procedure implementation is typical for multivariate experimentation.
A quantitative experiment is an experiment in which the independent variable can decrease or increase. The series of its possible values is a continuum, that is, a continuous sequence of quantities. These values, as a rule, can be expressed numerically, since the NP has units of measurement. Depending on the nature of the NP, its quantitative representation can be carried out in different ways. For example, time interval (duration), dosage, weight, concentration, number of elements. These are physical indicators. The quantitative expression of NP can be realized through psychological indicators: both psychophysical and psychometric.
The quantitative nature of NP does not yet guarantee the receipt of metric (interval and proportional) experimental data, but it is an essential prerequisite for them.
A qualitative experiment is one in which the independent variable has no quantitative variation. Its meanings appear only as various qualitative modifications. Examples: sex differences in populations, modal differences in signals, etc. The limiting case of a qualitative representation of NP is its presence or absence. For example: presence (absence) of interference.
The qualitative nature of the NP does not necessarily lead to non-metric experimental results. But obtaining metric data is usually more problematic here than in quantitative experiments.
Home experiences for children 4 years old require imagination and knowledge simple laws chemistry and physics. “If these sciences were not very good at school, you will have to make up for lost time,” many parents will think. This is not so, experiments can be very simple, not requiring special knowledge, skills and reagents, but at the same time explaining the fundamental laws of nature.
Experiments for children at home will help, using a practical example, to explain the properties of substances and the laws of their interaction, arouse interest in independent research of the world around them. Interesting physical experiments will teach children to be observant, help to think logically, establishing patterns between events that occur and their consequences. Perhaps the kids will not become great chemists, physicists or mathematicians, but they will forever keep fond memories of parental attention in their souls.
In this article, you will learn
Unfamiliar paper
Kids like to make appliques out of paper, draw pictures. Some children of 4 years old learn the art of origami with their parents. Everyone knows that paper is soft or thick, white or colored. And what is an ordinary one capable of White list paper if you experiment with it?
Revived paper flower
An asterisk is cut out of a sheet of paper. Its rays bend inward in the form of a flower. Water is collected in a cup and an asterisk is lowered onto the surface of the water. After a while, the paper flower, as if alive, will begin to open. The water will wet the cellulose fibers that make up the paper and straighten them.
Sturdy bridge
This paper experience will be interesting for children 3 years old. Ask the little ones how to place an apple in the middle of a thin sheet of paper between two glasses so that it does not fall. How do you make a paper bridge strong enough to support the weight of an apple? We fold a sheet of paper with an accordion and put it on the supports. It now supports the weight of an apple. This is explained by the fact that the shape of the structure has changed, which made the paper strong enough. On the property of materials it becomes stronger depending on the form, the designs of many architectural creations, for example, the Eiffel Tower, are based.
Revived snake
Scientific evidence of upward movement of warm air can be cited using simple experience... A snake is cut out of paper, cutting a circle in a spiral. Bringing a kite back to life is easy. A small hole is made in her head and suspended by a string over a heat source (battery, heater, burning candle). The snake will start spinning rapidly. The reason for this phenomenon is a warm upward flow of air, which unwinds the kite. Similarly, you can make paper birds or butterflies, beautiful and colorful, by hanging them from the ceiling in an apartment. They will rotate from the movement of the air, as if flying.
Who is stronger
This entertaining experiment will help to establish which paper shape is more durable. For the experiment, you will need three sheets of office paper, glue and several thin books. A cylindrical column is glued from one sheet of paper, a triangular column from another, and a rectangular column from the third. They put the "columns" vertically and test them for strength, carefully placing the books on top. As a result of the experiment, it turns out that the triangular column is the weakest, and the cylindrical is the strongest - it will support the greatest weight. It is not for nothing that the columns in churches and buildings are made precisely of a cylindrical shape, the load on them is distributed evenly over the entire area.
Amazing salt
Ordinary salt is in every home today, no cooking is complete without it. You can try to make beautiful children's crafts out of this available product... All you need is salt, water, wire and a little patience.
Salt has interesting properties. It can attract water to itself, dissolving in it, while increasing the density of the solution. But in a supersaturated solution, the salt turns into crystals again.
To conduct an experiment with wire salt, a beautiful symmetrical snowflake or other figurine is bent. Dissolve the salt in a jar of warm water until it stops dissolving. A bent wire is dipped into a jar and placed in the shade for several days. As a result, the wire will become overgrown with salt crystals, and will look like a beautiful ice snowflake that will not melt.
Water and ice
Water exists in three aggregate states: steam, liquid and ice. The purpose of this experience is to introduce children to the properties of water and ice and compare them.
Water is poured into 4 ice cube trays and placed in the freezer. To make it more interesting, you can tint the water before freezing with different dyes. Cold water is poured into a cup, and two ice cubes are thrown into it. Simple ice boats or icebergs will float on the surface of the water. This experience will prove that ice is lighter than water.
While the boats are sailing, sprinkle the remaining ice cubes with salt. They watch what will happen. Across a short time, before the indoor fleet in the cup still has time to go to the bottom (if the water is rather cold), the cubes sprinkled with salt will begin to crumble. This is because the freezing point of salt water is lower than normal.
Fire that does not burn
In ancient times, when Egypt was a powerful country, Moses fled from the wrath of Pharaoh and grazed herds in the wilderness. One day he saw a strange bush that was burning and did not burn. It was a special fire. But can objects that are engulfed in an ordinary flame remain safe and sound? Yes, this is possible, it can be proved with the help of experience.
For the experiment, you will need a piece of paper or a banknote. A tablespoon of rubbing alcohol and two tablespoons of water. The paper is moistened with water so that the water is absorbed into it, sprinkled with alcohol on top and set on fire. Fire appears. This is burning alcohol. When the fire goes out, the paper will remain intact. Experimental result the explanation is very simple - the combustion temperature of alcohol, as a rule, is not enough to evaporate the moisture with which the paper is impregnated.
Natural indicators
If the kid wants to feel like a real chemist, you can make special paper for him, which will change color depending on the acidity of the environment.
The natural indicator is prepared from red cabbage juice, which contains anthocyanin. This substance changes color depending on which liquid it comes into contact with. In an acidic solution, paper impregnated with anthocyanin will be colored in yellow, will turn green in a neutral solution, and blue in an alkaline solution.
To prepare the natural indicator, take filter paper, a head of red cabbage, cheesecloth and scissors. Chop the cabbage thinly and squeeze the juice through cheesecloth, wrinkling it with your hands. Saturate a sheet of paper with juice and dry. Then cut the indicator made into strips. The child can dip the piece of paper into four different liquids: milk, juice, tea or soapy water, and watch the color of the indicator change.
Friction electrification
In ancient times, people noticed the special ability of amber to attract light objects if rubbed with a woolen cloth. They did not yet have knowledge of electricity, so they explained this property by the spirit living in the stone. It is from Greek name amber - electron and the word electricity occurred.
Such amazing properties not only amber possesses. A simple experiment can be done to see how a glass stick or plastic comb attracts small pieces of paper to it. To do this, the glass must be rubbed with silk, and the plastic with wool. They will begin to attract small pieces of paper that will stick to them. After a while, this ability of objects will disappear.
You can discuss with children that this phenomenon is due to electrification by friction. Sparks may be generated if the fabric is rubbed against an object quickly. Lightning in the sky and thunder are also a consequence of the friction of air currents and the occurrence of electricity discharges in the atmosphere.
Solutions of different densities - interesting details
You can get a multi-colored rainbow in a glass of liquids of different colors by preparing jelly and pouring it layer by layer. But there is an easier way, although not as tasty.
To carry out the experiment, you will need sugar, vegetable oil, ordinary water and dyes. A concentrated sweet syrup is prepared from sugar, and pure water is colored with a dye. Sugar syrup is poured into a glass, then gently along the wall of the glass so that the liquids do not mix, pour clean water, at the end add vegetable oil. The sugar syrup should be cold and the colored water warm. All liquids will remain in the glass like a small rainbow, without mixing with each other. At the bottom there will be the densest sugar syrup, water at the top, and oil, as the lightest, will be on top of the water.
Color explosion
Another interesting experiment can be carried out using different densities vegetable oil and water, making a color explosion in the jar. For the experiment, you will need a jar of water, a few tablespoons of vegetable oil, food colors. In a small container, mix several dry food colors with two tablespoons of vegetable oil. Dry grains of colorants do not dissolve in oil. Now the oil is poured into a jar of water. Heavy grains of dyes will settle to the bottom, gradually being released from the oil, which will remain on the surface of the water, forming colored swirls, as if from an explosion.
Home volcano
Geographic knowledge can be less boring for a four-year-old if you showcase a volcanic eruption on an island. To carry out the experiment, you will need baking soda, vinegar, 50 ml of water and the same amount of detergent.
A small plastic cup or bottle is placed in a volcano's mouth, molded from colored plasticine. But first, they pour into a glass baking soda, pour water, tinted red and detergent... When the makeshift volcano is ready, a little vinegar is poured into its mouth. A violent foaming process begins, due to the fact that soda and vinegar react. From the mouth of the volcano begins to pour out "lava" formed by red foam.
Experiments and experiments for children 4 years old, as you have seen, do not need complex reagents. But they are no less exciting, especially with an interesting story about the reason for what is happening.