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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 completely illustrative 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.
It will take: 2 balls, candle, matches, water.
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.
You will need: plastic bag, pencils, water.
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 water will hardly 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.
You will need: a balloon, a wooden skewer and some dishwashing liquid.
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.
It will take: 4 glasses of water, food coloring, cabbage leaves or white flowers.
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 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.
It will take: 2 eggs, 2 glasses of water, salt.
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.
Broken pencil
Arrow experiment
This will surprise not only children, but also adults!
With children, you can still conduct a couple of Piaget's experiments. For example, take the same amount of water and pour it into different glasses (for example, wide and low, and the second one - narrow and high.) And then ask in which water is more?
You can also put the same number of coins (or buttons) in two rows (one below the other). Ask if the number is the same in two rows. Then, removing one coin from one row, move the rest apart so that the length of this row is the same as the top one. And again ask if it is the same now, etc. Give it a try - the answers will surely surprise you!
Ebbinghaus illusion (Ebbinghaus) or Titchener's circles- optical illusion of perception of relative sizes. The most famous version of this illusion is that two circles, identical in size, are placed side by side, with large circles around one of them, while the other is surrounded by small circles; the first circle seems to be smaller than the second.
The two orange circles are exactly the same size; however, the left circle appears to be smaller
Müller-Lyer illusion
The illusion is that the segment framed by the “points” appears to be shorter than the segment framed by the “tail” arrows. The illusion was first described by the German psychiatrist Franz Müller-Lyer in 1889
Or else, for example, an optical illusion - first you see black, then white
Even more optical illusions
And finally, the toy-illusion - Thaumatrope.
When you rotate a small piece of paper quickly with two designs applied on different sides, they are perceived as one. You can make such a toy yourself by drawing or pasting the corresponding images (several common thaumatropes - flowers and a vase, a bird and a cage, a beetle and a bank) on thick enough paper and attach ropes on the sides for twisting. Or even easier - attach to a stick like a lollipop and quickly rotate it between your palms.
And a couple more pictures. What do you see on them?
By the way, in our store you can buy ready-made sets for experiments in the field of optical illusions!
How to put a flat mirror on a drawn rectangle to get an image: a triangle, a quadrangle, a pentagon. Equipment: a flat mirror, a sheet of paper with a square drawn on it.
Answer
FRAGMENT OF THE FILM
Watson, I have a little assignment for you, ”Sherlock Holmes said quickly, shaking his friend’s hand. - Remember the murder of the jeweler, the police say that the driver of the car was driving at a very low speed, and the jeweler himself threw himself under the wheels of the car, so the driver did not have time to brake. But it seems to me that everything was wrong, the car was driving at high speed and the murder name It is difficult to determine the truth now, but it became known to me that this episode was accidentally caught on film, since the film was being filmed at that time. So I ask you, Watson, get this episode, literally a few meters of film.
But what will it give you? - asked Watson.
I don’t know yet, ”was the answer.
After a while, the friends sat in the cinema hall and, at the request of Sherlock Holmes, watched a small episode.
The car had already driven some distance, the jeweler was lying on the road almost motionless. A cyclist on a sports racing bike is passing by the lying jeweler.
Note, Watson, a cyclist has the same speed as a car. The distance between the cyclist and the car does not change during the entire episode.
And what follows from this? - Watson wondered.
Wait a minute, let's watch the episode again, - Holmes calmly whispered.
The episode was repeated. Sherlock Holmes was thoughtful.
Watson, have you noticed the cyclist? the detective asked again.
Yes, their speeds were the same, - confirmed Dr. Watson.
Have you paid attention to the wheels of the cyclist? Holmes inquired.
Wheels, like wheels, consist of three spokes located at an angle of 120 ° - an ordinary racing bike, the doctor reasoned.
But how did you count the number of spokes? - asked the famous detective.
Very simply, looking at the episode, I got the impression that ... the cyclist is standing still, since the wheels do not rotate.
But the cyclist was moving, - said Sherlock Holmes.
Moved, but the wheels did not rotate, - Watson confirmed.
Russian light
In 1876 in London at the exhibition of precise physical instruments
ditch Russian inventor Pavel Nikolaevich I blochkov demonstrated to the visitors an extraordinary electricity a candle. Similar in shape to the usual stearic acid, eh that candle burned with a blinding light. In the same year, "Yablochkov's candles" appeared on the streets of Paris. Placed in white matte balls, they gave a bright pleasant light. Va short time a wonderful candle of Russian inventors forfought universal recognition. "Yablochkov's candles" were illuminated the best hotels, streets and parks of the largest cities in Europe, Accustomed to the dim light of candles and kerosene llamas people of the last century admired "Yablochkov's candles". New light was called "Russian light", "northern light". Newspapers forWestern European countries wrote: “Light comes to us from the north - from Russia ”,“ Russia - the homeland of light ”.Introduction
1.Literary review
1.1. The history of the development of geometric optics
1.2. Basic concepts and laws of geometric optics
1.3. Prism elements and optical materials
2. Experimental part
2.1 Materials and experimental technique
2.2. Experimental results
2.2.1. Demonstration experiments using a glass prism with a refractive angle of 90º
2.2.2. Demonstration experiments using a glass prism filled with water, with a refractive angle of 90º
2.2.3. Demonstration experiments using a hollow glass prism, and filled with air, with a refractive angle of 74º
2.3. Discussion of experimental results
List of used literature
Introduction
The decisive role of experiment in the study of physics at school corresponds to the main principle of the natural sciences, in accordance with which experiment is the basis for the cognition of phenomena. Demonstration experiments contribute to the creation of physical concepts. Among the demonstration experiments, one of the most important places is occupied by experiments in geometric optics, which make it possible to clearly show the physical nature of light and demonstrate the basic laws of light propagation.
In this work, the problem of setting up experiments in geometric optics using a prism in high school is investigated. The most illustrative and interesting experiments in optics were selected using equipment that can be purchased by any school or made independently.
Literature review
1.1 The history of the development of geometric optics.
Optics belongs to such sciences, the initial ideas of which arose in ancient times. Throughout its centuries-old history, it has experienced continuous development, and at present it is one of the fundamental physical sciences, enriching itself with the discoveries of more and more new phenomena and laws.
The most important problem of optics is the question of the nature of light. The first ideas about the nature of light appeared in ancient times. Ancient thinkers tried to understand the essence of light phenomena based on visual sensations. The ancient Hindus thought that the eye was of a "fiery nature." The Greek philosopher and mathematician Pythagoras (582-500 BC) and his school believed that visual sensations arise from the fact that "hot vapors" emanate from the eyes to objects. In their further development, these views took on a clearer form in the form of the theory of visual rays, which was developed by Euclid (300 BC). According to this theory, vision is due to the fact that "visual rays" emanate from the eyes, which feel with their ends of the body and create visual sensations. Euclid is the founder of the doctrine of the rectilinear propagation of light. Applying mathematics to the study of light, he established the laws of light reflection from mirrors. It should be noted that for the construction of a geometric theory of light reflection from mirrors, the nature of the origin of light does not matter, but only the property of its rectilinear propagation is important. The patterns found by Euclid are preserved in modern geometric optics. The refraction of light was also familiar to Euclid. At a later time, similar views were developed by Ptolemy (70-147 AD). They paid great attention to the study of the phenomena of light refraction; in particular, Ptolemy made many measurements of the angles of incidence and refraction, but he failed to establish the law of refraction. Ptolemy noticed that the position of the luminaries in the sky changes due to the refraction of light in the atmosphere.
In addition to Euclid, other ancient scientists knew the effect of concave mirrors. Archimedes (287-212 BC) is credited with burning an enemy fleet using a system of concave mirrors, which he used to collect the sun's rays and direct it to Roman ships. A certain step forward was made by Empedocles (492-432 BC), who believed that outflows are directed from luminous bodies to the eyes, and outflows emanate from the eyes toward the bodies. When these outflows meet, visual sensations arise. The famous Greek philosopher, founder of atomism, Democritus (460-370 BC) completely rejects the concept of visual rays. According to the views of Democritus, vision is due to the fall on the surface of the eye of small atoms emanating from objects. Epicurus (341-270 BC) later adhered to similar views. The famous Greek philosopher Aristotle (384-322 BC), who believed that the cause of visual sensations lies outside the human eye, was also a decisive opponent of the "theory of visual rays". Aristotle made an attempt to explain colors as a consequence of the mixture of light and darkness.
It should be noted that the views of ancient thinkers were mainly based on the simplest observations of natural phenomena. Ancient physics did not have the necessary foundation in the form of experimental research. Therefore, the teaching of the ancients about the nature of light is speculative. Nevertheless, although these views are for the most part only ingenious guesses, they certainly had a great influence on the further development of optics.
The Arab physicist Algazen (1038) developed a number of problems in optics in his research. He studied the eye, the refraction of light, the reflection of light in concave mirrors. When studying the refraction of light, Algazei, in contrast to Ptolemy, proved that the angles of incidence and refraction are not proportional, which was the impetus for further research in order to find the law of refraction. Algazen knows the magnifying power of spherical glass segments. On the question of the nature of light, Alhazen takes the right positions, rejecting the theory of visual rays. Algazen proceeds from the idea that rays emanate from each point of a luminous object, which, reaching the eye, cause visual sensations. Alhazen believed that light has a finite speed of propagation, which in itself represents a major step in understanding the nature of light. Alhazen gave the correct explanation for the fact that the Sun and Moon appear larger on the horizon than at their zenith; he attributed this to a deception of the senses.
Renaissance. In the field of science, the experimental method of studying nature is gradually winning. During this period, a number of outstanding inventions and discoveries were made in optics. Francis Mavrolik (1494-1575) is credited with a fairly accurate explanation of the glasses. Mavrolik also found that concave lenses do not collect but scatter rays. He found that the lens is the most important part of the eye, and made a conclusion about the causes of hyperopia and myopia as a consequence of the abnormal refraction of light by the lens. Next, we should mention the Italian Port (1538-1615), who in 1589 invented the camera obscura - the prototype of the future camera. A few years later, the main optical instruments were invented - the microscope and the telescope.
The invention of the microscope (1590) is associated with the name of the Dutch master optician Zachary Jansen. Telescopes began to be manufactured at about the same time (1608-1610) by Dutch opticians Zachary Jansen, Jacob Metzius and Hans Lippersgey. The invention of these optical instruments led in the following years to major discoveries in astronomy and biology. The German physicist and astronomer N. Kepler (1571-1630) carried out fundamental work on the theory of optical instruments and physiological optics, the founder of which he can rightfully be called. Kepler worked a lot on the study of light refraction.
Fermat's principle, named after the French scientist Pierre Fermat (1601-1665), who formulated it, was of great importance for geometric optics. This principle established that light between two points propagates along a path that takes a minimum of time to travel. It follows from this that Fermat, in contrast to Descartes, considered the speed of propagation of light to be finite. The famous Italian physicist Galilei (1564-1642) did not carry out systematic work devoted to the study of light phenomena. However, in optics, he also owns works that have brought science remarkable results. Galileo improved the telescope and first applied it to astronomy, in which he made outstanding discoveries that contributed to the substantiation of the latest views on the structure of the Universe, based on the Copernican heliocentric system. Galileo managed to create a telescope with a frame magnification of 30, which was many times greater than the magnification of the telescopes of its first inventors. With its help, he discovered mountains and craters on the surface of the Moon, discovered satellites near the planet Jupiter, discovered the stellar structure of the Milky Way, etc. Galileo tried to measure the speed of light in terrestrial conditions, but was unsuccessful due to the weakness of the experimental means available for this purpose ... Hence it follows that Galileo already had the correct idea of the final speed of light propagation. Galileo also observed sunspots. The priority of the discovery of sunspots by Galileo was challenged by the Jesuit scientist Pater Scheiner (1575-1650), who made precise observations of sunspots and solar torches using a telescope arranged according to Kepler's scheme. The remarkable thing about Scheiner's work is that he turned the telescope into a projection device, extending the eyepiece more than was necessary for clear vision with the eye, this made it possible to get an image of the Sun on a screen and demonstrate it at different degrees of magnification to several faces at the same time.
The 17th century is characterized by further progress in various fields of science, technology and production. Mathematics is undergoing significant development. Scientific societies and academies uniting scientists are being created in various European countries. Thanks to this, science becomes the property of wider circles, which contributes to the establishment of international relations in science. In the second half of the 17th century, the experimental method of studying natural phenomena finally won out.
The largest discoveries of this period are associated with the name of the brilliant English physicist and mathematician Isaac Newton / (1643-1727). The most important experimental discovery of Newton in optics is the dispersion of light in a prism (1666). Investigating the passage of a beam of white light through a triangular prism, Newton found that a beam of white light splits into an infinite set of colored rays that form a continuous spectrum. From these experiments, it was concluded that white light is a complex radiation. Newton also made the opposite experiment, collecting with the help of a lens colored rays formed after a ray of white light passed through a prism. As a result, he again received white light. Finally, Newton performed the experiment of mixing colors using a rotating circle, divided into several sectors, painted in the primary colors of the spectrum. When the disc rotated quickly, all the colors merged into one, giving the impression of white.
The results of these fundamental experiments Newton laid the foundation for the theory of colors, which until then had not been succeeded by any of his predecessors. According to the theory of colors, the color of a body is determined by those rays of the spectrum that this body reflects; the body absorbs other rays.
1.2 Basic concepts and laws of geometric optics. The branch of optics, which is based on the concept of light rays as straight lines along which light energy propagates, is called geometric optics. This name was given to it because all the phenomena of the propagation of light here can be investigated by geometric constructions of the path of rays, taking into account the law of reflection and refraction of light. This law is the basis of geometric optics.
However, where we are talking about phenomena, the interaction of light with obstacles, the dimensions of which are small enough, the laws of geometric optics are insufficient and it is necessary to use the laws of wave optics. Geometric optics makes it possible to disassemble the main phenomena associated with the passage of light through lenses and other optical systems, as well as with the reflection of light from mirrors. The concept of a light ray as an infinitely thin beam of light propagating in a rectilinear manner naturally leads to the laws of rectilinear propagation of light and independent propagation of light beams. It is these laws, together with the laws of refraction and reflection of light, that are the basic laws of geometric optics, which not only explain many physical phenomena, but also make it possible to carry out calculations and design of optical devices. All these laws were initially established as empirical, that is, based on experiments, observations.
Most people, remembering their school years, are sure that physics is a very boring subject. The course includes many tasks and formulas that will not be useful to anyone in later life. On the one hand, these statements are true, but like any subject, physics has another side of the coin. Only not everyone discovers it for themselves.
Perhaps our education system is to blame for this, or maybe the whole thing is in the teacher, who only thinks about the fact that it is necessary to reprimand the material approved from above, and does not seek to interest his students. Most often it is he who is to blame. However, if the children are lucky, and the lesson is taught by a teacher who loves his subject himself, then he can not only interest the students, but also help them discover something new. As a result, the children will start to attend such classes with pleasure. Of course, formulas are an integral part of this academic subject, there is no getting away from it. But there are also positive aspects. Experiments are of particular interest to schoolchildren. We will talk about this in more detail. Here are some fun physics experiences you can have with your child. It should be interesting not only for him, but also for you. It is likely that with the help of such activities you will instill in your child a genuine interest in learning, and "boring" physics will become his favorite subject. it is not difficult to carry out, this will require very few attributes, the main thing is that there is a desire. And maybe then you can replace your child's school teacher.
Consider some interesting physics experiments for little ones, because you need to start small.
To carry out this experiment, we need to cut out a small fish from thick paper (cardboard can be used), the length of which should be 30-50 mm. We make a round hole in the middle with a diameter of about 10-15 mm. Next, from the side of the tail, cut through a narrow channel (3-4 mm wide) to a round hole. Then we pour water into a basin and carefully place our fish there so that one plane lies on the water, and the other remains dry. Now you need to drop oil into the round hole (you can use an oiler from a sewing machine or bicycle). Oil, trying to spill over the surface of the water, will flow along the cut channel, and the fish, under the influence of the oil flowing back, will float forward.
We will continue to carry out entertaining experiments in physics with our child. We invite you to introduce your kid to the concept of a lever and how it helps to facilitate a person's work. For example, share that it can easily lift a heavy cabinet or sofa. And for clarity, show an elementary experiment in physics with the use of a lever. To do this, we need a ruler, a pencil and a couple of small toys, but always of different weights (that's why we called this experiment "The Elephant and the Pug"). We attach our Elephant and Pug to different ends of the ruler using plasticine, or ordinary thread (we just tie the toys). Now, if you put the ruler with the middle part on a pencil, then, of course, the elephant will drag, because it is heavier. But if you move the pencil towards the elephant, then the Pug will easily outweigh it. This is the principle of leverage. The ruler (lever) rests on the pencil - this place is the fulcrum. Further, the child should be told that this principle is used everywhere, it is the basis for the operation of a crane, swing and even scissors.
We'll need a jar of water and a utility net. It will not be a secret for anyone that if an open jar is turned over, water will pour out of it. Let's try? Of course, for this it is better to go outside. We put the can in the grid and begin to smoothly swing it, gradually increasing the amplitude, and as a result, we make a full revolution - one, second, third, and so on. No water is poured out. Interesting? Now let's make the water pour up. To do this, take a tin can and make a hole in the bottom. We put it in the grid, fill it with water and start rotating. A jet gushes from the hole. When the can is in the lower position, this does not surprise anyone, but when it flies up, the fountain continues to beat in the same direction, and not a drop from the neck. That's it. All this can explain the principle of inertia. When the bank rotates, it tends to fly away straight, but the grid does not let it go and forces it to describe circles. Water also tends to fly by inertia, and in the case when we made a hole in the bottom, nothing prevents it from escaping and moving in a straight line.
Now let's look at experiments in physics with displacement. You need to put a matchbox on the edge of the table and slowly move it. The moment it passes its average mark, a fall will occur. That is, the mass of the part extended beyond the edge of the countertop will exceed the weight of the remaining part, and the boxes will tip over. Now let's shift the center of mass, for example, put a metal nut inward (as close to the edge as possible). It remains to place the boxes in such a way that a small part of it remains on the table, and a large part hangs in the air. The fall will not happen. The essence of this experiment is that the entire mass is above the fulcrum. This principle is also used throughout. It is thanks to him that furniture, monuments, transport, and much more are in a stable position. By the way, the children's toy Vanka-vstanka is also built on the principle of displacement of the center of mass.
So, we will continue to consider interesting experiments in physics, but let's move on to the next stage - for schoolchildren in the sixth grade.
We need an empty tin can, a hammer, a nail, a rope. We punch a hole in the side wall at the very bottom with a nail and a hammer. Further, without pulling the nail out of the hole, bend it to the side. It is necessary that the hole is oblique. We repeat the procedure on the second side of the can - you need to do it so that the holes turn out opposite each other, but the nails are bent in different directions. In the upper part of the vessel we punch two more holes, through them we pass the ends of a rope or thick thread. We hang the container and fill it with water. Two oblique fountains will begin to erupt from the lower holes, and the can will begin to rotate in the opposite direction. Space rockets work on this principle - the flame from the nozzles of the engine beats in one direction, and the rocket flies in the other.
Let's conduct an experiment with mass density and find out how you can make an egg float. Experiments in physics with different densities are best done using the example of fresh and salt water. Take a jar filled with hot water. We put an egg in it, and it will immediately drown. Next, pour table salt into the water and stir. The egg begins to float, and the more salt, the higher it will rise. This is because salt water has a higher density than fresh water. So, everyone knows that in the Dead Sea (its water is the saltiest) it is almost impossible to drown. As you can see, experiments in physics can significantly increase your child's horizons.
Seventh grade students begin to study atmospheric pressure and its effect on the objects around us. To expand on this topic deeper, it is better to conduct appropriate experiments in physics. Atmospheric pressure affects us, although it remains invisible. Let's take an example with a balloon. Each of us can cheat him. Then we place it in a plastic bottle, put the edges on the neck and fix it. Thus, air can only enter the balloon, and the bottle will become an airtight vessel. Now let's try to inflate the balloon. We will not succeed, since the atmospheric pressure in the bottle will not allow us to do this. When we blow, the ball begins to displace the air in the vessel. And since our bottle is airtight, it has nowhere to go, and it begins to shrink, thereby becoming much denser than the air in the ball. Accordingly, the system is leveled and the balloon cannot be inflated. Now let's make a hole in the bottom and try to inflate the balloon. In this case, there is no resistance, the displaced air leaves the bottle - the atmospheric pressure is equalized.
As you can see, experiments in physics are not at all complicated and quite interesting. Try to interest your child - and learning will be completely different for him, he will begin to attend classes with pleasure, which in the end will affect his academic performance.
