Various physical experiments. Interesting experiments in physics for children

Experiments at home are great way introduce children to the basics of physics and chemistry, and facilitate the understanding of complex abstract laws and terms through visual demonstration. Moreover, for their implementation it is not necessary to acquire expensive reagents or special equipment. After all, without hesitation, we conduct experiments every day at home - from adding slaked soda to the dough to connecting batteries to a flashlight. Read on to find out how easy, simple and safe it is to conduct interesting experiments.

Chemical experiments at home

Does the image of a professor with a glass flask and scorched eyebrows immediately appear in your head? Don't worry, our chemical experiments at home are completely safe, interesting and useful. Thanks to them, the child will easily remember what exo- and endothermic reactions are and what is the difference between them.

So, let's make hatching dinosaur eggs that can be successfully used as bath bombs.

For experience you need:

• small dinosaur figurines;
• baking soda;
• vegetable oil;
• lemon acid;
• food coloring or liquid watercolors.

The order of the experiment

1. Pour ½ cup baking soda into a small bowl and add about ¼ tsp. liquid paints(or dissolve 1-2 drops of food coloring in ¼ tsp of water), mix the baking soda with your fingers to create an even color.
2. Add 1 tbsp. l. citric acid. Mix dry ingredients thoroughly.
3. Add 1 tsp. vegetable oil.
4. You should end up with a crumbly dough that barely sticks together when pressed. If it does not want to stick together at all, then slowly add ¼ tsp. butter until you reach the desired consistency.
5. Now take a dinosaur figurine and cover it with dough in the shape of an egg. It will be very brittle at first, so it should be left overnight (minimum 10 hours) for it to harden.
6. Then you can start a fun experiment: fill the bathroom with water and drop an egg into it. It will hiss furiously as it dissolves into the water. It will be cold when touched, as it is an endothermic reaction between an acid and a base, absorbing heat from the environment.

Please note that the bathroom may become slippery due to the addition of oil.

Elephant Toothpaste

Experiments at home, the result of which can be felt and touched, are very popular with children. These include this funny project, which ends with a large amount of dense lush colored foam.

To carry it out you will need:

• goggles for a child;
• dry active yeast;
• warm water;
• hydrogen peroxide 6%;
• dishwashing detergent or liquid soap (not antibacterial);
• funnel;
• plastic sequins (necessarily non-metallic);
• food colorings;
• bottle 0.5 l (it is best to take a bottle with a wide bottom, for greater stability, but a regular plastic one will do).

The experiment itself is extremely simple:

1. 1 tsp dissolve dry yeast in 2 tbsp. l. warm water.
2. In a bottle placed in a sink or dish with high sides, pour ½ cup of hydrogen peroxide, a drop of dye, glitter and some dishwashing liquid (several pumps on the dispenser).
3. Insert a funnel and pour in the yeast. The reaction will start immediately, so act quickly.

The yeast acts as a catalyst and speeds up the release of hydrogen from the peroxide, and when the gas interacts with the soap, it creates a huge amount of foam. This is an exothermic reaction, with the release of heat, so if you touch the bottle after the "eruption" stops, it will be warm. Since the hydrogen immediately escapes, it's just soap suds to play with.

Physics experiments at home

Did you know that lemon can be used as a battery? True, very weak. Experiments at home with citrus fruits will demonstrate to children the operation of a battery and a closed electrical circuit.

For the experiment you will need:

• lemons - 4 pcs.;
• galvanized nails - 4 pcs.;
• small pieces of copper (you can take coins) - 4 pcs.;
• alligator clips with short wires (about 20 cm) - 5 pcs.;
• small light bulb or flashlight - 1 pc.

Let there be light

Here's how to do the experience:

1. Roll on a hard surface, then lightly squeeze the lemons to release the juice inside the skins.
2. Insert one galvanized nail and one piece of copper into each lemon. Line them up.
3. Connect one end of the wire to a galvanized nail and the other end to a piece of copper in another lemon. Repeat this step until all fruits are connected.
4. When you are done, you should be left with one 1 nail and 1 piece of copper that are not connected to anything. Prepare your light bulb, determine the polarity of the battery.
5. Connect the remaining piece of copper (plus) and nail (minus) to the plus and minus of the flashlight. Thus, a chain of connected lemons is a battery.
6. Turn on a light bulb that will work on the energy of fruits!

To repeat such experiments at home, potatoes, especially green ones, are also suitable.

How it works? Lemon acid, contained in a lemon, reacts with two different metals, which causes the ions to move in one direction, creating an electric current. All chemical sources of electricity work on this principle.

Summer fun

You don't have to stay indoors to do some experiments. Some experiments will work better outdoors, and you won't have to clean anything up after they're done. These include interesting experiments at home with air bubbles, and not simple ones, but huge ones.

To make them you will need:

• 2 wooden sticks 50-100 cm long (depending on the age and height of the child);
• 2 metal screw-in ears;
• 1 metal washer;
• 3 m cotton cord;
• bucket with water;
• any detergent - for dishes, shampoo, liquid soap.

Here's how to conduct spectacular experiments for children at home:

1. Screw metal ears into the ends of the sticks.
2. Cut the cotton cord into two parts, 1 and 2 m long. You can not exactly adhere to these measurements, but it is important that the proportion between them is 1 to 2.
3. Put a washer on a long piece of rope so that it sags evenly in the center, and tie both ropes to the ears on the sticks, forming a loop.
4. Mix a small amount of detergent in a bucket of water.
5. Gently dipping the loop on the sticks into the liquid, start blowing giant bubbles. To separate them from each other, carefully bring the ends of the two sticks together.

What is the scientific component of this experience? Explain to the children that bubbles are held together by surface tension, the attractive force that holds the molecules of any liquid together. Its action is manifested in the fact that spilled water collects in drops that tend to acquire a spherical shape, as the most compact of all that exists in nature, or that water, when poured, collects in cylindrical streams. At the bubble, a layer of liquid molecules is clamped on both sides by soap molecules, which increase its surface tension when distributed over the surface of the bubble, and prevent it from quickly evaporating. As long as the sticks are kept open, the water is held in the form of a cylinder; as soon as they are closed, it tends to a spherical shape.

Here are some experiments at home you can do with children.

Introduction

Without a doubt, all our knowledge begins with experience.
(Kant Emmanuel. German philosopher g. g)

Physical experiments in an entertaining way introduce students to the various applications of the laws of physics. Experiments can be used in the classroom to draw students' attention to the phenomenon being studied, with repetition and consolidation. educational material, at physical evenings. Entertaining experiments deepen and expand students' knowledge, contribute to the development of logical thinking, instill interest in the subject.

The role of experiment in the science of physics

That physics is a young science
Can't say for sure here.
And in ancient times knowing science,
Always strive to reach it.

The purpose of teaching physics is specific,
To be able to apply all knowledge in practice.
And it is important to remember - the role of the experiment
Must be in the first place.

Know how to plan and execute experiments.
Analyze and bring to life.
Build a model, put forward a hypothesis,
Strive to reach new heights

The laws of physics are based on facts established by experience. Moreover, the interpretation of the same facts often changes in the course of historical development physics. Facts accumulate as a result of observations. But at the same time, they cannot be limited only to them. This is only the first step towards knowledge. Next comes the experiment, the development of concepts that allow qualitative characteristics. To make observations general conclusions, to find out the causes of phenomena, it is necessary to establish quantitative relationships between quantities. If such a dependence is obtained, then a physical law is found. If a physical law is found, then there is no need to put in each separate case experience, it is enough to perform the corresponding calculations. Having studied experimentally the quantitative relationships between the quantities, it is possible to identify patterns. Based on these regularities, a general theory of phenomena is developed.

Therefore, without experiment there can be no rational teaching of physics. The study of physics involves the widespread use of the experiment, the discussion of the features of its formulation and the observed results.

Entertaining experiments in physics

The description of the experiments was carried out using the following algorithm:

Name of the experiment Necessary instruments and materials for the experiment Stages of the experiment Explanation of the experiment

Experience #1 Four floors

Devices and materials: glass, paper, scissors, water, salt, red wine, sunflower oil, colored alcohol.

Stages of the experiment

Let's try to pour four different liquids into a glass so that they do not mix and stand one above the other in five floors. However, it will be more convenient for us to take not a glass, but a narrow glass expanding towards the top.

Pour salted tinted water into the bottom of a glass. Roll out “Funtik” paper and bend its end at a right angle; cut off its tip. The hole in the Funtik should be the size of pinhead. Pour red wine into this cone; a thin stream should flow out of it horizontally, break against the walls of the glass and flow down it into salt water.
When the layer of red wine is equal in height to the height of the layer of tinted water, stop pouring the wine. From the second cone, pour sunflower oil into a glass in the same way. Pour a layer of colored alcohol from the third horn.

https://pandia.ru/text/78/416/images/image002_161.gif" width="86 height=41" height="41">, tinted alcohol has the smallest.

Experience #2 Amazing Candlestick

Devices and materials: candle, nail, glass, matches, water.

Stages of the experiment

Isn't it an amazing candlestick - a glass of water? And this candlestick is not bad at all.

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Figure 3

Explanation of experience

The candle goes out because the bottle is “flown around” with air: the jet of air is broken by the bottle into two streams; one flows around it on the right, and the other on the left; and they meet approximately where the flame of a candle stands.

Experience number 4 Spinning snake

Devices and materials: thick paper, candle, scissors.

Stages of the experiment

Cut a spiral out of thick paper, stretch it a little and put it on the end of the bent wire. Holding this coil over the candle in an updraft of air will cause the snake to spin.

Explanation of experience

The snake rotates because the air expands under the influence of heat and the transformation of warm energy into motion.

https://pandia.ru/text/78/416/images/image007_56.jpg" width="300" height="225 src=">

Figure 5

Explanation of experience

Water has a higher density than alcohol; it will gradually enter the vial, displacing the mascara from there. Red, blue or black liquid will rise in a thin stream from the bubble upwards.

Experiment No. 6 Fifteen matches on one

Devices and materials: 15 matches.

Stages of the experiment

Put one match on the table, and 14 matches across it so that their heads stick up and the ends touch the table. How to lift the first match, holding it by one end, and with it all the other matches?

Explanation of experience

To do this, you only need to put one more, fifteenth match on top of all the matches, in the hollow between them.

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Figure 7

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Figure 9

Experience No. 8 Paraffin motor

Devices and materials: candle, knitting needle, 2 glasses, 2 plates, matches.

Stages of the experiment

To make this motor, we don't need electricity or gasoline. We need only ... a candle for this.

Heat the needle and stick it with their heads into the candle. This will be the axis of our engine. Place a candle with a knitting needle on the edges of two glasses and balance. Light the candle at both ends.

Explanation of experience

A drop of paraffin will fall into one of the plates placed under the ends of the candle. The balance will be disturbed, the other end of the candle will pull and fall; at the same time, a few drops of paraffin will drain from it, and it will become lighter than the first end; it rises to the top, the first end will fall, drop a drop, it will become easier, and our motor will start to work with might and main; gradually fluctuations of the candle will increase more and more.

https://pandia.ru/text/78/416/images/image013_40.jpg" width="300" height="225 src=">

Figure 11

Demonstration Experiments

1. Diffusion of liquids and gases

Diffusion (from Latin diflusio - spreading, spreading, scattering), the transfer of particles of different nature, due to the chaotic thermal motion of molecules (atoms). Distinguish between diffusion in liquids, gases and solids

Demonstration experiment "Observation of diffusion"

Devices and materials: cotton wool, ammonia, phenolphthalein, diffusion observation device.

Stages of the experiment

Take two pieces of cotton wool. We moisten one piece of cotton wool with phenolphthalein, the other with ammonia. Let's bring the branches together. Staining of cotton wool is observed in pink color due to the phenomenon of diffusion.

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Figure 13

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Figure 15

Let us prove that the phenomenon of diffusion depends on temperature. The higher the temperature, the faster diffusion proceeds.

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Figure 17

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Figure 19

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Figure 21

3. Pascal's ball

Pascal's ball is a device designed to demonstrate the uniform transfer of pressure exerted on a liquid or gas in a closed vessel, as well as the rise of a liquid behind a piston under the influence of atmospheric pressure.

To demonstrate the uniform transmission of pressure produced on a liquid in a closed vessel, it is necessary, using a piston, to draw water into the vessel and firmly fit the ball onto the nozzle. By pushing the piston into the vessel, demonstrate the outflow of liquid from the holes in the ball, paying attention to the uniform outflow of liquid in all directions.

Winter will begin soon, and with it the long-awaited time. In the meantime, we suggest that you take your child to no less exciting experiences at home, because you want miracles not only for New Year but also every day.

This article will focus on experiments that clearly demonstrate to children such physical phenomena as: atmospheric pressure, the properties of gases, the movement of air currents and from various objects.

These will cause surprise and delight in the baby, and even a four-year-old can repeat them under your supervision.

How to fill a bottle with water without hands?

We will need:

• a bowl of cold and tinted water for clarity;
• hot water;
• Glass bottle.

Pour hot water into the bottle several times so that it warms up well. We turn the empty hot bottle upside down and lower it into a bowl with cold water. We observe how water from the bowl is drawn into the bottle and, contrary to the law of communicating vessels, the water level in the bottle is much higher than in the bowl.

Why is this happening? Initially, a well-heated bottle is filled with warm air. As the gas cools, it contracts to fill a smaller and smaller volume. Thus, a low-pressure medium is formed in the bottle, where water is sent to restore balance, because atmospheric pressure presses on the water from the outside. Colored water will flow into the bottle until the pressure inside and outside the glass vessel equalizes.

Dancing coin

For this experience we will need:

• a glass bottle with a narrow neck that can be completely blocked by a coin;
• coin;
• water;
• freezer.

We leave an empty open glass bottle in the freezer (or outside in winter) for 1 hour. We take out the bottle, moisten the coin with water and put it on the neck of the bottle. After a few seconds, the coin will begin to bounce on the neck and make characteristic clicks.

This behavior of the coin is explained by the ability of gases to expand when heated. Air is a mixture of gases, and when we took the bottle out of the refrigerator it was filled with cold air. At room temperature, the gas inside began to heat up and increase in volume, while the coin blocked its exit. Here the warm air began to push out the coin, and at one time it began to bounce on the bottle and click.

It is important that the coin is wet and fits snugly to the neck, otherwise the focus will not work and warm air will freely leave the bottle without tossing a coin.

Glass - non-spill

Invite the child to turn the glass filled with water so that the water does not spill out of it. Surely the baby will refuse such a scam or at the first attempt will pour water into the basin. Teach him the next trick. We will need:

• a glass of water;
• a piece of cardboard;
• basin / sink for safety net.

We cover the glass with water with cardboard, and holding the latter with our hand, we turn the glass over, after which we remove the hand. This experiment is best done over the basin / sink, because. if the glass is kept upside down for a long time, the cardboard will eventually get wet and water will spill. Paper instead of cardboard is better not to use for the same reason.

Discuss with your child: why does the cardboard prevent water from flowing out of the glass, because it is not glued to the glass, and why does the cardboard not immediately fall under the influence of gravity?

Do you want to play with your child easily and with pleasure?

At the moment of getting wet, the cardboard molecules interact with water molecules, being attracted to each other. From this point on, water and cardboard interact as one. In addition, wet cardboard prevents air from entering the glass, which prevents the pressure inside the glass from changing.

At the same time, not only water from the glass presses on the cardboard, but also the air from the outside, which forms the force of atmospheric pressure. It is atmospheric pressure that presses the cardboard to the glass, forming a kind of lid, and prevents the water from pouring out.

Experience with a hair dryer and a strip of paper

We continue to surprise the child. We build a structure from books and attach a strip of paper to them from above (we did this with adhesive tape). The paper hangs from the books as shown in the photo. You choose the width and length of the strip, focusing on the power of the hair dryer (we took 4 by 25 cm).

Now turn on the hair dryer and direct the air stream parallel to the lying paper. Despite the fact that the air does not blow on the paper, but next to it, the strip rises from the table and develops as if in the wind.

Why does this happen and what makes the strip move? Initially, gravity acts on the strip and atmospheric pressure presses. The hair dryer creates a strong airflow along the paper. In this place, a zone of low pressure is formed in the direction of which the paper deviates.

Shall we blow out the candle?

We begin to teach the baby to blow even before a year old, preparing him for his first birthday. When the child has grown up and fully mastered this skill, offer him through the funnel. In the first case, positioning the funnel in such a way that its center corresponds to the level of the flame. And the second time, so that the flame is along the edge of the funnel.

Surely the child will be surprised that all his efforts in the first case will not give the proper result in the form of an extinguished candle. Moreover, in the second case, the effect will be instantaneous.

Why? When air enters the funnel, it is evenly distributed along its walls, therefore maximum speed flow is observed at the edge of the funnel. And in the center, the air speed is small, which does not allow the candle to go out.

Shadow from the candle and from the fire

We will need:

• candle;
• flashlight.

We light the battle and place it against a wall or other screen and illuminate it with a flashlight. A shadow from the candle itself will appear on the wall, but there will be no shadow from the fire. Ask the child why this happened?

The thing is that the fire itself is a source of light and transmits other light rays through itself. And since the shadow appears when the side illumination of an object that does not transmit rays of light, the fire cannot give a shadow. But not everything is so simple. Depending on the combustible substance, the fire can be filled with various impurities, soot, etc. In this case, you can see a blurry shadow, which is exactly what these inclusions give.

Did you like a selection of experiments to conduct at home? Share with friends by clicking on the buttons social networks so that other mothers will please their babies with interesting experiments!

BEI "Koskovskaya secondary school"

Kichmengsko-Gorodets municipal district

Vologda region

Educational project

"Physical experiment at home"

Completed:

7th grade students

Koptyaev Artem

Alekseevskaya Xenia

Alekseevskaya Tanya

Supervisor:

Korovkin I.N.

March-April-2016.

Content

Introduction

Nothing in life is better than your own experience.

Scott W.

At school and at home, we got acquainted with many physical phenomena and we wanted to make home-made devices, equipment and conduct experiments. All our experiments allow us to get deeper knowledge the world and in particular physics. We describe the process of making equipment for the experiment, the principle of operation and the physical law or phenomenon demonstrated by this device. The experiments carried out interested students from other classes.

Target: make a device from available improvised means to demonstrate a physical phenomenon and use it to tell about a physical phenomenon.

Hypothesis: made devices, demonstrations will help to know physics deeper.

Tasks:

Study the literature on conducting experiments with your own hands.

Watch video demonstration of experiments

Build experiment equipment

Hold a demo

Describe the physical phenomenon being demonstrated

Improve the material base of the physicist's office.

EXPERIENCE 1. Fountain model

Target : show the simplest model of the fountain.

Equipment : plastic bottle, dropper tubes, clamp, balloon, cuvette.

Ready product

The course of the experiment:

We will make 2 holes in the cork. Insert the tubes, attach a ball to the end of one.

Fill the balloon with air and close with a clip.

Pour into a bottle of water and put it in a cuvette.

Let's watch the flow of water.

Result: We observe the formation of a fountain of water.

Analysis: compressed air in the balloon acts on the water in the bottle. The more air in the balloon, the higher the fountain will be.

EXPERIENCE 2. Carthusian diver

(Pascal's law and Archimedean force.)

Target: demonstrate Pascal's law and Archimedes' force.

Equipment: plastic bottle,

pipette (a vessel closed at one end)

Ready product

The course of the experiment:

Take a plastic bottle with a capacity of 1.5-2 liters.

Take a small vessel (pipette) and load it with copper wire.

Fill the bottle with water.

Press down on the top of the bottle with your hands.

Watch the phenomenon.

Result : we observe the dipping of the pipette and the ascent when pressing on the plastic bottle ..

Analysis : the force will compress the air over the water, the pressure is transferred to the water.

According to Pascal's law, pressure compresses the air in the pipette. As a result, the Archimedean force decreases. The body is sinking. Stop squeezing. The body floats.

EXPERIENCE 3. Pascal's law and communicating vessels.

Target: demonstrate the operation of Pascal's law in hydraulic machines.

Equipment: two syringes of different sizes and a plastic tube from a dropper.

Ready product.

The course of the experiment:

1. Take two syringes different size and connect with a tube from a dropper.

2.Fill with incompressible liquid (water or oil)

3. Push down on the plunger of the smaller syringe. Observe the movement of the plunger of the larger syringe.

4. Push the plunger of the larger syringe. Observe the movement of the plunger of the smaller syringe.

Result : We fix the difference in the applied forces.

Analysis : According to Pascal's law, the pressure created by the pistons is the same. Therefore: how many times the piston is so many times and the force generated by it is greater.

EXPERIENCE 4. Dry from water.

Target : show the expansion of hot air and the contraction of cold air.

Equipment : a glass, a plate of water, a candle, a cork.

Ready product.

The course of the experiment:

1. pour water into a plate and place a coin on the bottom and a float on the water.

2. invite the audience to get a coin without getting their hands wet.

3. light a candle and put it in the water.

4. cover with a warm glass.

Result: Watching the movement of water in a glass.

Analysis: when air is heated, it expands. When the candle goes out. The air cools and its pressure drops. Atmospheric pressure will push the water under the glass.

EXPERIENCE 5. Inertia.

Target : show the manifestation of inertia.

Equipment : Wide-mouthed bottle, cardboard ring, coins.

Ready product.

The course of the experiment:

1. We put a paper ring on the neck of the bottle.

2. put coins on the ring.

3. with a sharp blow of the ruler we knock out the ring

Result: watch the coins fall into the bottle.

Analysis: inertia is the ability of a body to maintain its speed. When hitting the ring, the coins do not have time to change speed and fall into the bottle.

EXPERIENCE 6. Upside down.

Target : Show the behavior of a liquid in a rotating bottle.

Equipment : Wide-mouthed bottle and rope.

Ready product.

The course of the experiment:

1. We tie a rope to the neck of the bottle.

2. pour water.

3. rotate the bottle over your head.

Result: water does not spill out.

Analysis: At the top, gravity and centrifugal force act on the water. If the centrifugal force is greater than gravity, then the water will not pour out.

EXPERIENCE 7. Non-Newtonian fluid.

Target : Show the behavior of a non-Newtonian fluid.

Equipment : bowl.starch. water.

Ready product.

The course of the experiment:

1. In a bowl, dilute starch and water in equal proportions.

2. demonstrate the unusual properties of the liquid

Result: a substance has the properties of a solid and a liquid.

Analysis: with a sharp impact, the properties of a solid body are manifested, and with a slow impact, the properties of a liquid.

Conclusion

As a result of our work, we:

conducted experiments proving the existence of atmospheric pressure;

created home-made devices that demonstrate the dependence of liquid pressure on the height of the liquid column, Pascal's law.

We liked to study pressure, make home-made devices, conduct experiments. But there are many interesting things in the world that you can still learn, so in the future:

We will continue to study this interesting science

We hope that our classmates will be interested in this problem, and we will try to help them.

In the future, we will conduct new experiments.

Conclusion

It is interesting to watch the experience conducted by the teacher. Conducting it yourself is doubly interesting.

And to conduct an experiment with a device made and designed by one's own hands is of great interest to the whole class. In such experiments, it is easy to establish a relationship and draw a conclusion about how a given installation works.

Conducting these experiments is not difficult and interesting. They are safe, simple and useful. New research ahead!

Literature

Evenings in physics high school/ Comp. EM. Braverman. Moscow: Education, 1969.

Extracurricular work in physics / Ed. O.F. Kabardin. M.: Enlightenment, 1983.

Galperstein L. Entertaining physics. M.: ROSMEN, 2000.

GeagleL.A. Entertaining experiments in physics. Moscow: Enlightenment, 1985.

Goryachkin E.N. Methodology and technique of physical experiment. M.: Enlightenment. 1984

Mayorov A.N. Physics for the curious, or what you don't learn in class. Yaroslavl: Academy of Development, Academy and K, 1999.

Makeeva G.P., Tsedrik M.S. Physical paradoxes and entertaining questions. Minsk: Narodnaya Asveta, 1981.

Nikitin Yu.Z. Fun hour. M .: Young Guard, 1980.

Experiments in a home laboratory // Kvant. 1980. No. 4.

Perelman Ya.I. Entertaining mechanics. Do you know physics? M.: VAP, 1994.

Peryshkin A.V., Rodina N.A. Physics textbook for grade 7. M.: Enlightenment. 2012

Peryshkin A.V. Physics. - M .: Bustard, 2012

Entertaining experiences.
extracurricular activity for the middle classes.

Extra-curricular physics event for middle grades "Entertaining experiments"

Event goals:

Develop cognitive interest, interest in physics;
- develop literacy monologue speech using physical terms, develop attention, observation, the ability to apply knowledge in a new situation;
- to teach children to benevolent communication.

Teacher: Today we will show you entertaining experiments. Look carefully and try to explain them. The most distinguished in the explanation will receive prizes - good and excellent marks in physics.

(Students in grade 9 show experiments, and students in grades 7-8 explain)

Experience 1 "Without getting your hands wet"

Equipment: plate or saucer, coin, glass, paper, matches.

Conduct: Put a coin on the bottom of a plate or saucer and pour some water. How to get a coin without even getting your fingertips wet?

Solution: Light the paper, put it into the glass for a while. Turn the heated glass upside down and place on a saucer next to the coin.

As the air in the glass is heated, its pressure will increase and some of the air will escape. The remaining air will cool after a while, the pressure will decrease. Under the action of atmospheric pressure, water will enter the glass, freeing the coin.

Experience 2 "Raising a dish of soap"

Equipment: a plate, a piece of laundry soap.

How to do it: Pour water into a bowl and drain immediately. The surface of the plate will be damp. Then a bar of soap, strongly pressing against the plate, turn several times and lift it up. At the same time, the plate will also rise with soap. Why?

Explanation: The rise of the dish of soap is due to the attraction of the molecules of the dish and the soap.

Experience 3 "Magic water"

Equipment: a glass of water, a sheet of thick paper.

Conduct: This experience is called "Magic Water". Fill a glass with water to the brim and cover with a sheet of paper. Let's turn the glass. Why doesn't water pour out of an overturned glass?

Explanation: Water is held by atmospheric pressure, i.e. atmospheric pressure is greater than the pressure produced by water.

Notes: Experience is better with a thick-walled vessel.
When turning the glass, a piece of paper must be held by hand.

Experience 4 "Tearable paper"

Equipment: two tripods with clutches and paws, two paper rings, rail, meter.

Conduct: We hang the paper rings on tripods at the same level. We put a rail on them. With a sharp blow with a meter or a metal rod in the middle of the rail, it breaks, and the rings remain intact. Why?

Explanation: The interaction time is very short. Therefore, the rail does not have time to transfer the received impulse to the paper rings.

Notes: The width of the rings is 3 cm. The rail is 1 meter long, 15-20 cm wide and 0.5 cm thick.

Experience 5 "Heavy Newspaper"

Equipment: rail 50-70 cm long, newspaper, meter.

Conduct: Put a rail on the table, a fully unfolded newspaper on it. If you slowly put pressure on the hanging end of the ruler, then it falls, and the opposite one rises along with the newspaper. If you sharply hit the end of the rail with a meter or hammer, then it breaks, and the opposite end with the newspaper does not even rise. How to explain it?

Explanation: The paper is under pressure from above. atmospheric air. By slowly pressing the end of the ruler, air penetrates under the newspaper and partially balances the pressure on it. With a sharp blow, due to inertia, air does not have time to instantly penetrate under the newspaper. The air pressure on the newspaper from above is greater than from below, and the rail breaks.

Notes: The rail must be laid so that its end of 10 cm hangs. The newspaper should fit snugly against the rail and the table.

Experience 6

Equipment: tripod with two clutches and legs, two demonstration dynamometers.

Conduct: We will fix two dynamometers on a tripod - a device for measuring force. Why are their readings the same? What does this mean?

Explanation: bodies act on each other with forces equal in magnitude and opposite in direction. (Newton's third law).

Experience 7

Equipment: two sheets of paper of the same size and weight (one of them is crumpled).

Implementation: Release both sheets at the same time from the same height. Why does a crumpled sheet of paper fall faster?

Explanation: A crumpled sheet of paper falls faster because there is less air resistance acting on it.

But in a vacuum, they would fall at the same time.

Experience 8 "How quickly the candle goes out"

Equipment: a glass vessel with water, a stearin candle, a nail, matches.

Conduct: Light a candle and lower it into a vessel of water. How fast will the candle go out?

Explanation: It seems that the flame will be filled with water as soon as the segment of the candle that protrudes above the water burns out and the candle goes out.

But, burning down, the candle decreases in weight and floats under the action of the Archimedean force.

Note: Attach a small weight (nail) to the bottom of the candle so that it floats in the water.

Experience 9 "Fireproof paper"

Equipment: metal rod, strip of paper, matches, candle (spirit lamp)

Conduct: Wrap the rod tightly with a strip of paper and bring it into the flame of a candle or spirit lamp. Why doesn't paper burn?

Explanation: Iron, being a good conductor of heat, removes heat from paper so it does not catch fire.

Experience 10 "Fireproof scarf"

Equipment: tripod with clutch and foot, alcohol, handkerchief, matches.

Implementation: Clamp a handkerchief (previously moistened with water and wrung out) in the foot of the tripod, douse it with alcohol and set it on fire. Despite the flame engulfing the handkerchief, it will not burn. Why?

Explanation: The heat released during the combustion of alcohol completely went to the evaporation of water, so it cannot ignite the fabric.

Experience 11 "Fireproof thread"

Equipment: a tripod with a clutch and a foot, a feather, a regular thread and a thread soaked in a saturated solution of table salt.

Conduct: We hang a feather on a thread and set it on fire. The thread burns out, and the feather falls. And now let's hang a feather on a magic thread and set it on fire. As you can see, the magic thread burns out, but the feather remains hanging. Explain the secret of the magic thread.

Explanation: The magic thread was soaked in a salt solution. When the thread is burned, the feather is held on by fused salt crystals.

Note: The thread should be soaked 3-4 times in a saturated salt solution.

Experience 12 "Water boils in a paper pot"

Equipment: a tripod with a clutch and a foot, a paper saucepan on threads, a spirit lamp, matches.

Conduct: Hang a paper pan on a tripod.

Can you boil water in this pot?

Explanation: All the heat released during combustion goes to heat the water. In addition, the temperature of the paper pot does not reach the ignition temperature.

Interesting questions.

Teacher: While the water boils, you can ask the audience questions:

What grows upside down? (icicle)

Bathed in water, but remained dry. (Goose, duck)

Why don't waterfowl get wet in the water? (The surface of their feathers is covered with a thin layer of fat, and water does not wet the oily surface.)

From the ground and the child will lift, but over the fence and the strongman will not throw. (Fluff)

During the day the window is broken, at night it is inserted. (hole)

The results of the experiments are summed up.

Grading.

2015-