Beautiful experiments in chemistry for schoolchildren. Chemical experiments

Chemical experience of bromine with aluminum

If a few milliliters of bromine are placed in a test tube made of heat-resistant glass and a piece of aluminum foil is carefully lowered into it, then after a while (necessary for bromine to penetrate through the oxide film), a violent reaction will begin. From the heat released, aluminum melts and, in the form of a small fireball, rolls over the surface of bromine (the density of liquid aluminum is less than the density of bromine), rapidly decreasing in size. The test tube is filled with bromine vapor and white smoke, consisting of the smallest crystals of aluminum bromide:

2Al+3Br 2 → 2AlBr 3 .

It is also interesting to observe the reaction of aluminum with iodine. Mix in a porcelain cup a small amount of powdered iodine with aluminum powder. While the reaction is not noticeable: in the absence of water, it proceeds extremely slowly. Using a long pipette, drop a few drops of water on the mixture, which plays the role of an initiator, and the reaction will proceed vigorously - with the formation of a flame and the release of purple vapors of iodine.

Chemical experiments with gunpowder: how gunpowder explodes!

Smoky, or black, gunpowder is a mixture of potassium nitrate (potassium nitrate - KNO 3), sulfur (S) and coal (C). It ignites at a temperature of about 300 °C. Gunpowder can also explode on impact. It consists of an oxidizing agent (nitrate) and a reducing agent (charcoal). Sulfur is also a reducing agent, but its main function is to bind potassium into a strong compound. During the combustion of gunpowder, the following reaction occurs:

2KNO 3 + ЗС + S → K 2 S + N 2 + 3СО 2,
- as a result of which a large volume of gaseous substances is released. The use of gunpowder in military affairs is connected with this: the gases formed during the explosion and expanding from the heat of the reaction push the bullet out of the gun barrel. It is easy to verify the formation of potassium sulfide by smelling the barrel of a gun. It smells of hydrogen sulfide - a product of the hydrolysis of potassium sulfide.

Chemical experiments with saltpeter: fiery inscription

Spectacular chemical experience can be carried out with potassium nitrate. Let me remind you that nitrates are complex substances - salts of nitric acid. In this case, we need potassium nitrate. Its chemical formula is KNO 3 . On a sheet of paper, draw a contour, a drawing (for greater effect, let the lines do not intersect!). Prepare a concentrated solution of potassium nitrate. For information: in 15 ml hot water 20 g of KNO 3 are dissolved. Then, using a brush, we impregnate the paper along the drawn contour, while leaving no gaps or gaps. let the paper dry. Now you need to touch a burning splinter to some point on the contour. Immediately a "spark" will appear, which will slowly move along the contour of the picture until it closes it completely. Here's what happens: Potassium nitrate decomposes according to the equation:

2KNO 3 → 2 KNO 2 + O 2 .

Here KNO 2 +O 2 is a salt of nitrous acid. From the released oxygen, the paper chars and burns. For greater effect, the experiment can be carried out in a dark room.

Chemical experience of dissolving glass in hydrofluoric acid

Indeed, glass dissolves easily. Glass is a very viscous liquid. The fact that glass can dissolve can be verified by doing the following chemical reaction. Hydrofluoric acid is an acid formed by dissolving hydrogen fluoride (HF) in water. It is also called hydrofluoric acid. For greater clarity, let's take a thin speckle, on which we attach a weight. We lower the glass with a weight into a solution of hydrofluoric acid. When the glass dissolves in the acid, the weight will fall to the bottom of the flask.

Chemical experiments with smoke emission

Let's do a beautiful experiment to get thick white smoke. To do this, we need to prepare a mixture of potash (potassium carbonate K 2 CO 3) with an ammonia solution (ammonia). Mix the reagents: potash and ammonia. Add a solution to the resulting mixture of hydrochloric acid. The reaction will begin already at the moment when the flask with hydrochloric acid is brought close to the flask containing ammonia. Carefully add hydrochloric acid to the ammonia solution and observe the formation of a thick white vapor of ammonium chloride, the chemical formula of which is NH 4 Cl. The chemical reaction between ammonia and hydrochloric acid proceeds as follows:

HCl + NH 3 → NH 4 Cl

Chemical experiments: the glow of solutions

As noted above, the glow of solutions is a sign of a chemical reaction. Let's conduct another spectacular experiment, in which our solution will glow. For the reaction, we need a solution of luminol, a solution of hydrogen peroxide H 2 O 2 and crystals of red blood salt K 3. Luminol- a complex organic substance, the formula of which is C 8 H 7 N 3 O 2. Luminol is highly soluble in some organic solvents, while it does not dissolve in water. The glow occurs when luminol reacts with some oxidizing agents in an alkaline medium.

So, let's start: add a solution of hydrogen peroxide to luminol, then add a handful of red blood salt crystals to the resulting solution. For greater effect, try conducting the experiment in a dark room! As soon as the blood red salt crystals touch the solution, a cold blue glow will immediately be noticeable, which indicates the course of the reaction. The glow in a chemical reaction is called chemiluminescence

Another chemical experience with luminous solutions:

For it, we need: hydroquinone (formerly used in photographic equipment), potassium carbonate K 2 CO 3 (also known as "potash"), pharmacy solution of formalin (formaldehyde) and hydrogen peroxide. Dissolve 1 g of hydroquinone and 5 g of potassium carbonate K 2 CO 3 in 40 ml of pharmacy formalin (formaldehyde aqueous solution). Pour this reaction mixture into a large flask or bottle with a capacity of at least one liter. In a small vessel, prepare 15 ml of concentrated hydrogen peroxide solution. You can use hydroperite tablets - a combination of hydrogen peroxide with urea (urea will not interfere with the experiment). For more effect go to dark room when your eyes have adjusted to the dark, pour the hydrogen peroxide solution into large vessel with hydroquinone. The mixture will begin to foam (hence the need for a large vessel) and a distinct orange glow will appear!

The chemical reactions in which the glow appears do not occur only during oxidation. Sometimes the glow occurs during crystallization. The easiest way to observe it is table salt. Dissolve table salt in water, and take enough salt so that undissolved crystals remain at the bottom of the glass. Pour the resulting saturated solution into another glass and add concentrated hydrochloric acid to this solution drop by drop. The salt will begin to crystallize, and sparks will fly through the solution. It is most beautiful if the experience is set in the dark!

Chemical experiments with chromium and its compounds

Multicolored chrome!... The color of chromium salts can easily change from purple to green and vice versa. Let's carry out the reaction: let's dissolve in water a few purple crystals of chromium chloride CrCl 3 6H 2 O. When boiled, the purple solution of this salt turns green. When the green solution is evaporated, a green powder of the same composition as the original salt is formed. And if you saturate a green solution of chromium chloride cooled to 0 ° C with hydrogen chloride (HCl), its color will turn purple again. How to explain the observed phenomenon? This is a rare example of isomerism in inorganic chemistry - the existence of substances that have the same composition, but different structure and properties. In the violet salt, the chromium atom is bonded to six water molecules, and the chlorine atoms are counterions: Cl 3, and in green chromium chloride they change places: Cl 2H 2 O. In an acidic environment, dichromates are strong oxidizing agents. Their recovery products are Cr3+ ions:

K 2 Cr 2 O 7 + 4H 2 SO 4 + 3K 2 SO 3 → Cr 2 (SO 4) 3 + 4K 2 SO 4 + 4H 2 O.

At a low temperature, violet crystals of potassium chromium alum KCr (SO 4) 2 12H 2 O can be isolated from the resulting solution. The dark red solution obtained by adding concentrated sulfuric acid to a saturated aqueous solution of potassium dichromate is called “chromic peak”. In laboratories, it is used for washing and degreasing chemical glassware. The dishes are carefully rinsed with chromic, which is not poured into the sink, but is used repeatedly. In the end, the mixture becomes green - all the chromium in such a solution has already passed into the Cr 3+ form. A particularly strong oxidizing agent is chromium (VI) oxide CrO 3 . With it, you can light an alcohol lamp without matches: just touch the wick moistened with alcohol with a stick with several crystals of this substance. When CrO 3 is decomposed, dark brown chromium (IV) oxide powder CrO 2 can be obtained. It has ferromagnetic properties and is used in the magnetic tapes of some types of audio cassettes. The body of an adult contains only about 6 mg of chromium. Many compounds of this element (especially chromates and dichromates) are toxic, and some of them are carcinogens, i.e. capable of causing cancer.

Chemical experiments: the reducing properties of iron

This type chemical reaction refers to redox reactions. To carry out the reaction, we need diluted (5%) aqueous solutions of iron (III) chloride FeCl 3 and the same solution of potassium iodide KI. So, a solution of iron (III) chloride is poured into one flask. Then add a few drops of potassium iodide solution to it. Observe the color change of the solution. The liquid will take on a reddish-brown color. The following chemical reactions will take place in the solution:

2FeCl 3 + 2KI → 2FeCl 2 + 2KCl + I 2

KI + I 2 → K

Another chemical experiment with iron compounds. For it, we need dilute (10–15%) aqueous solutions of iron (II) sulfate FeSO 4 and ammonium thiocyanate NH 4 NCS, bromine water Br 2. Let's start. Pour a solution of iron(II) sulfate into one flask. 3-5 drops of ammonium thiocyanate solution are also added there. We notice that there are no signs of chemical reactions. Of course, iron(II) cations do not form colored complexes with thiocyanate ions. Now add bromine water to this flask. But now the iron ions "given themselves out" and colored the solution in a blood-red color. this is how the (III) ion of valence iron reacts with thiocyanate ions. Here's what happened in the flask:

Fe(H 2 O) 6 ] 3+ + n NCS– (n–3) – + n H 2 O

Chemical experiment on the dehydration of sugar with sulfuric acid

Concentrated sulfuric acid dehydrates the sugar. Sugar is a complex organic substance whose formula is C 12 H 22 O 11. Here's how it goes. Powdered sugar is placed in a tall glass beaker, slightly moistened with water. Then a little concentrated sulfuric acid is added to the wet sugar. mix gently and quickly with a glass rod. The stick is left in the middle of the glass with the mixture. After 1 - 2 minutes, the sugar begins to turn black, swell and rise in the form of a voluminous, loose black mass, taking the glass rod with it. The mixture in the glass gets very hot and smokes a little. In this chemical reaction, sulfuric acid not only removes water from sugar, but also partially turns it into coal.

C 12 H 22 O 11 + 2H 2 SO 4 (conc.) → 11C + CO 2 + 13H 2 O + 2SO 2

The released water during such a chemical reaction is mainly absorbed by sulfuric acid (sulfuric acid "greedily" absorbs water) with the formation of hydrates, hence the strong release of heat. BUT carbon dioxide CO 2, which is obtained during the oxidation of sugar, and sulfur dioxide SO 2 raise the charring mixture up.

Chemical experiment with the disappearance of an aluminum spoon

Let's carry out another funny chemical reaction: for this we need an aluminum spoon and mercury nitrate (Hg (NO 3) 2). So, let's take a spoon, clean it with a fine-grained sandpaper then degrease with acetone. Dip a spoon for a few seconds in a solution of mercury nitrate (Hg (NO 3) 2). (remember that mercury compounds are poisonous!). As soon as the surface of the aluminum spoon in the mercury solution becomes gray, the spoon must be removed, washed with boiled water and dried (wetting, but not wiping). After a few seconds, the metal spoon will turn into fluffy white flakes, and soon only a grayish pile of ash will be left of it. This is what happened:

Al + 3 Hg(NO 3) 2 → 3 Hg + 2 Al(NO 3) 3 .

In the solution, at the beginning of the reaction, a thin layer of aluminum amalgam (an alloy of aluminum and mercury) appears on the surface of the spoon. The amalgam then turns into fluffy white flakes of aluminum hydroxide (Al(OH) 3). The metal consumed in the reaction is replenished with new portions of aluminum dissolved in mercury. And, finally, instead of a shiny spoon, white Al (OH) 3 powder and tiny droplets of mercury remain on the paper. If after a solution of mercury nitrate (Hg (NO 3) 2) aluminum spoon immediately immersed in distilled water, then gas bubbles and white flakes will appear on its surface (hydrogen and aluminum hydroxide will be released).

Evening entertaining chemistry

When preparing a chemical evening, careful preparation of the teacher for conducting experiments is required.

The evening should be preceded by long, careful work with students, and one student should not be assigned more than two experiments.

The purpose of the chemistry evening- repeat the knowledge gained, deepen students' interest in chemistry and instill in them practical skills in developing and implementing experiments.

Description of the main stages of the evening of entertaining chemistry

I. Introductory speech of the teacher on the topic "The role of chemistry in the life of society."

II. Entertaining experiments in chemistry.

Leading (the role of the leader is performed by one of the students of the 10-11th grade):

Today we are having an evening of entertaining chemistry. Your task is to carefully follow the chemical experiments and try to explain them. And so, we begin! Experience No. 1: "Volcano".

Experience number 1. Description:

A participant in the evening pours powdered ammonium dichromate (in the form of a slide) onto an asbestos net, puts several heads of matches on the upper part of the slide and sets them on fire with a splinter.

Note: The volcano will look even more spectacular if you add a little powdered magnesium to the ammonium dichromate. Mix the components of the mixture immediately, because. magnesium burns vigorously and being in one place causes the scattering of hot particles.

The essence of the experiment is the exothermic decomposition of ammonium dichromate under local heating.

There is no smoke without fire, says an old Russian proverb. It turns out that with the help of chemistry you can get smoke without fire. And so, attention!

Experience number 2. Description:

The participant of the evening takes two glass rods, on which a little cotton wool is wound, and wets them: one in concentrated nitric (or hydrochloric) acid, the other in an aqueous 25% ammonia solution. Sticks should be brought to each other. White smoke rises from the sticks.

The essence of the experience is the formation of nitrate (chloride) ammonium.

And now we present to your attention the following experience - “Shooting Paper”.

Experience number 3. Description:

The participant of the evening takes out pieces of paper on a sheet of plywood, touches them with a glass rod. When you touch each leaf, a shot is heard.

Note: Narrow strips of filter paper are cut in advance and moistened in a solution of iodine in ammonia. After that, the strips are laid out on a sheet of plywood and left to dry until the evening. The shot is the stronger, the better the paper is impregnated with the solution and the more concentrated the solution of nitrogen iodide was.

The essence of the experiment is the exothermic decomposition of the fragile compound NI3*NH3.

I have an egg. Which one of you guys will peel it without breaking the shells?

Experience number 4. Description:

The participant of the evening places the egg in a crystallizer with a solution of hydrochloric (or acetic) acid. After a while, it pulls out an egg covered only with a shell membrane.

The essence of the experience is that the composition of the shell mainly includes calcium carbonate. In hydrochloric (acetic) acid, it turns into soluble calcium chloride (calcium acetate).

Guys, I have a figure of a man made of zinc in my hands. Let's dress him up.

Experience number 5. Description:

The participant of the evening lowers the figurine into a 10% lead acetate solution. The figurine is covered with a fluffy layer of lead crystals, reminiscent of fur clothing.

The essence of the experiment is that a more active metal displaces a less active metal from salt solutions.

Guys, is it possible to burn sugar without the help of fire? Let's check!

Experience number 6. Description:

The participant of the evening pours icing sugar (30 g) into a glass placed on a saucer, pours 26 ml of concentrated sulfuric acid into the same place and stirs the mixture with a glass rod. After 1-1.5 minutes, the mixture in the glass darkens, swells and rises above the edges of the glass in the form of a loose mass.

The essence of the experiment is that sulfuric acid removes water from sugar molecules, oxidizes carbon into carbon dioxide, and at the same time sulfur dioxide is formed. The released gases push the mass out of the glass.

What methods of making fire do you know?

Examples are given from the audience.

Let's try to do without these funds.

Experience number 7. Description:

A participant in the evening pours potassium permanganate (6 g) ground into powder on a piece of tin (or a tile) and drops glycerin on it from a pipette. After a while, a fire appears.

The essence of the experiment is that as a result of the reaction, atomic oxygen is released and glycerol ignites.

Other participant of the evening:

I will also get fire without matches, only in a different way.

Experience number 8. Description:

A participant in the evening sprinkles a small amount of potassium permanganate crystals on a brick and drips concentrated sulfuric acid on it. Around this mixture, he folds thin chips in the form of a fire, but so that they do not touch the mixture. Then he wets a small piece of cotton wool with alcohol and, holding his hand over the fire, squeezes a few drops of alcohol out of the cotton so that they fall on the mixture. The fire instantly lights up.

The essence of the experience is the vigorous oxidation of alcohol by oxygen, which is released during the interaction of sulfuric acid with potassium permanganate. The heat released during this reaction ignites the fire.

And now amazing lights!

Experience number 9. Description:

The participant of the evening puts cotton swabs moistened with ethyl alcohol into porcelain cups. On the surface of the tampons, he pours the following salts: sodium chloride, strontium nitrate (or lithium nitrate), potassium chloride, barium nitrate (or boric acid). On a piece of glass, the participant prepares a mixture (slurry) of potassium permanganate and concentrated sulfuric acid. He takes some of this mass with a glass rod and touches the surface of the tampons. Tampons flash and burn in different colors: yellow, red, purple, green.

The essence of the experience is that alkali and alkaline earth metal ions color the flame in different colors.

Dear children, I am so tired and hungry that I ask you to allow me to eat a little.

Experience number 10. Description:

The host addresses the participant of the evening:

Give me some tea and biscuits, please.

The participant of the evening gives the host a glass of tea and a white cracker.

The host moistens the cracker in tea - the cracker turns blue.

Leading :

Disgrace, you almost poisoned me!

Participant of the evening:

Excuse me, I must have mixed up the glasses.

The essence of the experiment - in the glass was a solution of iodine. The starch in the bread turned blue.

Guys, I received a letter, but there was a blank sheet of paper in the envelope. Who can help me find out what's wrong?

Experience number 11. Description:

A student from the audience (prepared in advance) touches a smoldering splinter to a pencil mark on a sheet of paper. The paper along the line of the drawing slowly burns out and the light, moving along the contour of the image, outlines it (the drawing can be arbitrary).

The essence of the experience is that the paper burns due to the oxygen of the saltpeter crystallized in its thickness.

Note: a drawing is preliminarily applied to a sheet of paper with a strong solution of potassium nitrate. It must be applied in one continuous line without intersections. From the outline of the drawing with the same solution, draw a line to the edge of the paper, marking its end with a pencil. When the paper dries, the pattern will become invisible.

Well, now, guys, let's move on to the second part of our evening. Chemical games!

III. Team games.

Participants of the evening are invited to break into groups. Each group takes part in the proposed game.

Game number 1. Chemical lotto.

The formulas of chemicals are written on the cards, laid out as in a regular loto, and the names of these substances are written on cardboard squares. The group members are given cards, and one of them pulls out the squares and names the substances. The winner is the member of the group who first closes all the fields of the card.

Game number 2. Chemical quiz.

A rope is stretched between the backs of two chairs. Sweets are tied to it on strings, to which pieces of paper with questions are attached. Group members take turns cutting candy with scissors. The player becomes the owner of the candy after answering the question attached to it.

The group members form a circle. They have chemical symbols and numbers in their hands. Two of the players are in the middle of the circle. On command they compose chemical formula substances from signs and numbers held by the other players. The participant who completes the formula the fastest wins.

The group members are divided into two teams. They are given cards with chemical formulas and numbers. They must write a chemical equation. The team that completes the equation first wins.

The evening ends with the presentation of prizes to the most active participants.

Who didn't believe in miracles as a child? To have fun and informative time with your baby, you can try to carry out experiments from entertaining chemistry. They are safe, interesting and educational. These experiments will answer many children's "why" and arouse interest in science and knowledge of the world. And today I want to tell you what experiments for children at home can be organized by parents.

pharaoh snake

This experiment is based on increasing the volume of the mixed reagents. In the process of burning, they transform and, wriggling, resemble a snake. The experiment got its name thanks to the biblical miracle, when Moses, who came to the pharaoh with a request, turned his rod into a snake.

For the experience you will need the following ingredients:

• ordinary sand;
• ethanol;
• crushed sugar;
• baking soda.

We impregnate the sand with alcohol, after that we form a small hill out of it and make a recess at the top. Then mix with a small spoon powdered sugar and a pinch of soda, then we fall asleep everything in an impromptu "crater". We set fire to our volcano, the alcohol in the sand begins to burn out, and black balls form. They are a decomposition product of soda and caramelized sugar.

After all the alcohol has burned out, the sand slide will turn black and a writhing "black pharaoh's snake" will form. This experiment looks more impressive with the use of real reagents and strong acids, which can only be used in a chemical laboratory.

You can do it a little easier and buy a calcium gluconate tablet at the pharmacy. Set it on fire at home, the effect will be almost the same, only the “snake” will quickly collapse.

Magic lamp

In stores, you can often see lamps, inside which a beautiful illuminated liquid moves and shimmers. Such lamps were invented in the early 60s. They work on the basis of paraffin and oil. At the bottom of the device is a built-in conventional incandescent lamp that heats the descending molten wax. Part of it reaches the top and falls, the other part heats up and rises, so we see a kind of “dance” of paraffin inside the container.

In order to carry out a similar experience at home with a child, we need:

• any juice;
• vegetable oil;
• tablets - pops;
• beautiful container.

We take a container and fill it with juice more than half. Add vegetable oil on top and throw a pop-up tablet there. It begins to “work”, the bubbles rising from the bottom of the glass capture the juice in themselves and form a beautiful seething in the oil layer. Then the bubbles that reach the edge of the glass burst, and the juice falls down. It turns out a kind of "cycle" of juice in a glass. Such magic lamps absolutely harmless, unlike paraffin, which a child can accidentally break and burn.

Balloon and Orange: An Experience for Toddlers

What will happen to a balloon if you drop orange or lemon juice on it? It will burst as soon as drops of citrus touch it. And then you can eat an orange with your baby. It's very entertaining and fun. For the experience, we need a couple of balloons and citrus. We inflate them and let the baby drip fruit juice on each and see what happens.

Why does the ball burst? It's all about a special chemical - limonene. It is found in citrus fruits and is often used in the cosmetics industry. When the juice comes into contact with the rubber of the balloon, a reaction occurs, limonene dissolves the rubber and the balloon bursts.

sweet glass

Amazing things can be made from caramelized sugar. In the early days of cinema, most fight scenes used this edible sweet glass. This is because it is less traumatic for actors during filming and is inexpensive. Its fragments can then be collected, melted down and made into props for the film.

Many in childhood made sugar cockerels or fudge, glass should be made according to the same principle. Pour water into a saucepan, heat a little, the water should not be cold. After that, pour sugar into it and bring to a boil. When the liquid boils, cook until the mass begins to gradually thicken and bubble strongly. The melted sugar in the container should turn into a viscous caramel, which, if lowered into cold water, will turn into glass.

Pour the prepared liquid onto the previously prepared and greased vegetable oil baking sheet, cool and sweet glass is ready.

During the cooking process, you can add dye to it and pour it into some interesting shape, and then treat and surprise everyone around.

Philosopher's nail

This entertaining experience is based on the principle of iron coppering. Named by analogy with a substance that, according to legend, could turn everything into gold, and was called the philosopher's stone. To conduct the experiment, we will need:

• iron nail;
• a fourth of a glass of acetic acid;
• food salt;
• soda;
• a piece of copper wire;
• glass container.

We take a glass jar and pour acid, salt into it and stir well. Be careful, vinegar is harsh bad smell. It can burn the baby's delicate airways. Then we put the copper wire into the resulting solution for 10-15 minutes, after some time we lower the iron nail previously cleaned with soda into the solution. After some time, we can see that a copper coating has appeared on it, and the wire has become shiny as new. How could this happen?

Copper reacts with acetic acid, a copper salt is formed, then copper ions on the surface of the nail change places with iron ions and form a plaque on its surface. And the concentration of iron salts increases in the solution.

Copper coins are not suitable for the experiment, since this metal itself is very soft, and to make the money stronger, its alloys with brass and aluminum are used.

Copper products do not rust over time, they are covered with a special green coating - patina, which prevents it from further corrosion.

DIY soap bubbles

Who didn't love blowing bubbles as a child? How beautifully they shimmer and burst merrily. You can just buy them at the store, but it will be much more interesting to create your own solution with your child and then blow bubbles.

It should be said right away that the usual mixture of laundry soap and water will not work. It produces bubbles that quickly disappear and are poorly blown. Most affordable way to prepare such a substance - mix two glasses of water with a glass detergent for dishes. If sugar is added to the solution, then the bubbles become stronger. They will fly for a long time and will not burst. And the huge bubbles that can be seen on stage with professional artists are obtained by mixing glycerin, water and detergent.

For beauty and mood, you can mix food paint into the solution. Then the bubbles will glow beautifully in the sun. You can create several different solutions and take turns using them with your child. It is interesting to experiment with color and create your own, new shade soap bubbles.

You can also try mixing the soap solution with other substances and see how they affect the blisters. Maybe you will invent and patent some new kind of your own.

Spy ink

This legendary invisible ink. What are they made from? Now there are so many films about spies and interesting intellectual investigations. You can invite your child to play a little secret agents.

The meaning of such ink is that they cannot be seen on paper with the naked eye. Only by applying a special effect, for example, heating or chemical reagents, can a secret message be seen. Unfortunately, most recipes for making them are ineffective and such ink leaves marks.

We will make special ones that are difficult to see without special detection. For this you will need:

• water;
• the spoon;
• baking soda;
• any source of heat;
• stick with cotton at the end.

Pour warm liquid into any container, then, while stirring, pour baking soda into it until it stops dissolving, i.e. the mixture will reach a high concentration. We put a stick with cotton on the end there and write something on paper with it. Let's wait until it dries, then bring the leaf to a lit candle or gas stove. After a while, you can see how the yellow letters of the written word appear on the paper. Make sure that during the development of the letters the leaf does not catch fire.

Fireproof money

This is a well-known and old experiment. For it you will need:

• water;
• alcohol;
• salt.

Take a deep glass container and pour water into it, then add alcohol and salt, stir well so that all the ingredients are dissolved. For ignition, you can take ordinary pieces of paper, if you don’t mind, then you can take a bill. Just take a small denomination, otherwise something may go wrong in the experience and the money will be spoiled.

Put strips of paper or money in a water-salt solution, after a while they can be removed from the liquid and set on fire. You can see that the flame covers the entire banknote, but it does not light up. This effect is explained by the fact that the alcohol in the solution evaporates, and the wet paper does not light up.

wish fulfilling stone

The process of growing crystals is very exciting, but time consuming. However, what you get as a result will be worth the time spent. The most popular is the creation of crystals from table salt or sugar.

Consider growing a "wish stone" from refined sugar. For this you will need:

• drinking water;
• granulated sugar;
• paper sheet;
• thin wooden stick;
• small container and glass.

Let's make a preparation first. To do this, we need to prepare a sugar mixture. Pour some water and sugar into a small container. We wait until the mixture boils, and boil until a syrupy state is formed. Then we lower the wooden stick there and sprinkle it with sugar, you need to do this evenly, in this case the resulting crystal will become more beautiful and even. Leave the base for the crystal overnight to dry and harden.

Let's prepare the syrup solution. Pour water into a large container and fall asleep, slowly stirring, sugar there. Then, when the mixture boils, boil it to the state of a viscous syrup. Remove from fire and let cool.

Cut out circles from paper and attach them to the end of a wooden stick. It will become a lid on which a wand with crystals is attached. We fill the glass with a solution and lower the workpiece there. We wait for a week, and the "stone of desires" is ready. If you put a dye in the syrup when cooking, it will turn out even more beautiful.

The process of creating crystals from salt is somewhat simpler. Here it will only be necessary to monitor the mixture and periodically change it in order to increase the concentration.

First of all, we create a blank. Pour into a glass container warm water, and gradually stirring, pour the salt until it stops dissolving. We leave the container for a day. After this time, you can find many small crystals in the glass, choose the largest one and tie it to a thread. Make a new salt solution and put a crystal there, it must not touch the bottom or the edges of the glass. This can lead to unwanted deformations.

After a couple of days, you can see that he has grown. The more often you change the mixture, increasing the concentration of salt content, the faster you can grow your wish stone.

glowing tomato

This experiment must be carried out strictly under the supervision of adults, since harmful substances are used for its implementation. The glowing tomato that will be created during this experiment is strictly forbidden to eat, it can lead to death or severe poisoning. We will need:

• ordinary tomato;
• syringe;
• sulfuric matter from matches;
• bleach;
• hydrogen peroxide.

We take a small container, put the previously prepared match sulfur there and pour in the bleach. We leave all this for a while, after which we draw the mixture into a syringe and inject it inside the tomato with different parties so that it glows evenly. To start the chemical process, hydrogen peroxide is needed, which we introduce through the trace from the petiole from above. We turn off the light in the room, and we can enjoy the process.

Egg in Vinegar: A Very Simple Experience

This is a simple and interesting ordinary acetic acid. For its implementation, you will need boiled egg and vinegar. Take a transparent glass container and lower the egg in the shell into it, then fill it to the top with acetic acid. You can see how bubbles rise from its surface, this is a chemical reaction. After three days, we can observe that the shell has become soft, and the egg is elastic, like a ball. If you point a flashlight at it, you can see that it glows. It is not recommended to conduct an experiment with a raw egg, since the soft shell may break when squeezed.

Do-it-yourself slime from PVA

This is a fairly common strange toy of our childhood. Currently, it is quite difficult to find it. Let's try to make slime at home. Its classic color is green, but you can use whatever you like. Try mixing several shades and create your own unique color.

For the experiment we need:

• glass jar;
• several small glasses;
• dye;
• PVA glue;
• regular starch.

Let's prepare three identical glasses with solutions that we will mix. Pour PVA glue into the first, water into the second, and starch into the third. First, pour water into the jar, then add glue and dye, mix everything thoroughly and then add starch. The mixture must be quickly mixed so that it does not thicken, and you can play with the finished slime.

How to quickly inflate a balloon

Soon the holiday and you need to inflate a lot of balloons? What to do? This unusual experience will help to facilitate the task. For him, we need a rubber ball, acetic acid and ordinary soda. It must be carried out carefully in the presence of adults.

Pour a pinch of baking soda into balloon and put it on the neck of a bottle of acetic acid so that the soda does not spill out, straighten the ball and let its contents fall into the vinegar. You will see how the chemical reaction will take place, it will begin to foam, releasing carbon dioxide and inflating the balloon.

That's all for today. Do not forget that it is better to conduct experiments for children at home under supervision, it will be both safer and more interesting. See you soon!

Not a single person, even the least bit familiar with the problems of modern education, will argue about the advantages of the Soviet system. However, it also had certain drawbacks, in particular, in the study of natural science subjects, the emphasis was often placed on providing a theoretical component, and practice was relegated to the background. At the same time, any teacher will confirm that The best way to arouse in a child an interest in these objects is to show some spectacular physical or chemical experience. This is especially important for initial stage study of such subjects and even long before that. In the second case, a special kit for chemical experiments, which can be used at home, can be a good help for parents. True, when purchasing such a gift, fathers and mothers should understand that they will also have to take part in classes, since such a “toy” in the hands of a child left unattended represents a certain danger.

What is a chemical experiment

First of all, you should understand what is at stake. It is generally accepted that chemical experiment- this is the manipulation of various organic and inorganic substances in order to establish their properties and reactions under various conditions. If we are talking about experiments that are carried out in order to arouse in the child the desire to explore the world around them, then they should be spectacular and at the same time simple. In addition, it is not recommended to choose options that require security special measures security.

Where to begin

First of all, you can tell the child that everything that surrounds us, including his own body, consists of various substances that interact. As a result, various phenomena can be observed: both those to which people have long been accustomed and do not pay attention to them, and very unusual ones. In this case, rust, which is a consequence of the oxidation of metals, or smoke from a fire, which is a gas released during the combustion of various objects, can be cited as an example. Then you can start showing simple chemical experiments.

"Float Egg"

A very interesting experiment can be shown using an egg and an aqueous solution of hydrochloric acid. To carry it out, you need to take a glass decanter or a wide glass and pour a 5% solution of hydrochloric acid onto the bottom. Then you need to lower the egg into it and wait a while.

Soon, on the surface of the egg shell, due to the reaction of hydrochloric acid and calcium carbonate contained in the shell, carbon dioxide bubbles will appear and lift the egg up. Having reached the surface, the gas bubbles will burst, and the "load" will again go to the bottom of the dish. The process of lifting and diving the egg will continue until all the eggshell has been dissolved in the hydrochloric acid.

"Secret Signs"

Interesting chemical experiments can be done with sulfuric acid. For example, with a cotton swab dipped in a 20% sulfuric acid solution, figures or letters are drawn on paper and wait for the liquid to dry. Then the sheet is ironed with a hot iron and black letters begin to appear. This experience will be even more spectacular if you hold the leaf over the flame of a candle, but this must be done very carefully, trying not to set fire to the paper.

"Fire Lettering"

The previous experience can be done differently. To do this, draw a contour of a figure or letter on a piece of paper with a pencil and prepare a composition consisting of 20 g of KNO 3 dissolved in 15 ml of hot water. Then, with a brush, saturate the paper along the pencil lines so that there are no gaps. As soon as the audience is ready, and the sheet is dry, you need to bring a burning splinter to the inscription at only one point. Immediately a spark will appear, which will “run” along the outline of the drawing until it reaches the end of the line.

Surely young viewers will be interested in why such an effect is achieved. Explain that when heated, potassium nitrate turns into another substance, potassium nitrite, and releases oxygen, which supports combustion.

"Fireproof Handkerchief"

Children will certainly be interested in the experience with "fireproof" fabric. To demonstrate it, 10 g of silicate glue is dissolved in 100 ml of water and a piece of cloth or handkerchief is moistened with the resulting liquid. Then it is squeezed out and, using tweezers, immersed in a container with acetone or gasoline. Immediately set fire to the fabric with a splinter and watch how the flame "devours" the handkerchief, but it remains intact.

"Blue Bouquet"

Simple chemical experiments can be very spectacular. We invite you to surprise the viewer by using paper flowers, the petals of which should be smeared with natural starch glue. Then the bouquet should be placed in a jar, a few drops of iodine alcohol tincture should be put on the bottom and the lid should be tightly closed. In a few minutes, a "miracle" will happen: the flowers will turn blue, because the iodine vapor will cause the starch to change its color.

"Christmas decorations"

An original chemistry experience that will give you beautiful jewelry for a mini-Christmas tree, it will turn out if you use a saturated solution (1:12) of potassium alum KAl (SO 4) 2 with the addition blue vitriol CuSO4 (1:5).

First you need to make a frame of a figurine from a wire, wrap it with white woolen threads and lower them into a pre-prepared mixture. After a week or two, crystals will grow on the workpiece, which should be varnished so that they do not crumble.

"Volcanoes"

A very effective chemical experiment will turn out if you take a plate, plasticine, baking soda, table vinegar, red dye and dishwashing liquid. Next, you need to do the following:

• divide a piece of plasticine into two parts;
• roll one into a flat pancake, and fashion a hollow cone from the second, at the top of which you need to leave a hole;
• put the cone on a plasticine base and connect it so that the "volcano" does not let water through;
• put the structure on a tray;
• pour "lava", consisting of 1 tbsp. l. drinking soda and a few drops of liquid food coloring;
• when the audience is ready, pour vinegar into the "vent" and watch the violent reaction, during which carbon dioxide is released, and red foam flows out of the volcano.

As you can see, home chemical experiments can be very diverse, and all of them will interest not only children, but also adults.

My personal experience of teaching chemistry has shown that such a science as chemistry is very difficult to study without any initial knowledge and practice. Schoolchildren very often run this subject. I personally observed how a student of the 8th grade at the word "chemistry" began to frown, as if he had eaten a lemon.

Later it turned out that because of dislike and misunderstanding of the subject, he skipped school in secret from his parents. Of course, the school curriculum is designed in such a way that the teacher must give a lot of theory at the first chemistry lessons. Practice, as it were, fades into the background precisely at the moment when the student cannot yet independently realize whether he needs this subject in the future. This is primarily due to the laboratory equipment of schools. In big cities, things are better now with reagents and instruments. As for the province, as well as 10 years ago, and at present, many schools do not have the opportunity to conduct laboratory classes. But the process of studying and fascination with chemistry, as well as with other natural sciences, usually begins with experiments. And it is no coincidence. Many famous chemists, such as Lomonosov, Mendeleev, Paracelsus, Robert Boyle, Pierre Curie and Maria Sklodowska-Curie (schoolchildren also study all these researchers in physics classes) have already started experimenting since childhood. The great discoveries of these great people were made in home chemical laboratories, since chemistry classes at institutes were available only to wealthy people.

And, of course, the most important thing is to interest the child and convey to him that chemistry surrounds us everywhere, so the process of studying it can be very exciting. This is where home chemistry experiments come in handy. Observing such experiments, one can further look for an explanation of why things happen this way and not otherwise. And when a young researcher encounters similar concepts at school lessons, the teacher’s explanations will be more understandable to him, since he will already have his own experience in conducting home chemical experiments and the knowledge gained.

It is very important to start science studies with the usual observations and real life examples that you think will be the best for your child. Here are some of them. Water is Chemical substance, consisting of two elements, as well as gases dissolved in it. Man also contains water. We know that where there is no water, there is no life. A person can live without food for about a month, and without water - only a few days.

River sand is nothing but silicon oxide, and also the main raw material for glass production.

A person himself does not suspect it and carries out chemical reactions every second. The air we breathe is a mixture of gases - chemicals. In the process of exhalation, another complex substance is released - carbon dioxide. We can say that we ourselves are a chemical laboratory. You can explain to the child that washing hands with soap is also a chemical process of water and soap.

An older child who, for example, has already begun to study chemistry at school, can be explained that almost all elements can be found in the human body. periodic system D. I. Mendeleev. In a living organism, not only all chemical elements are present, but each of them performs some biological function.

Chemistry is also medicines, without which at present many people cannot live even a day.

Plants also contain the chemical chlorophyll, which gives the leaf its green color.

Cooking is hard chemical processes. Here you can give an example of how the dough rises when yeast is added.

One of the options for getting a child interested in chemistry is to take an individual outstanding researcher and read the story of his life or watch an educational film about him (films about D.I. Mendeleev, Paracelsus, M.V. Lomonosov, Butlerov are now available).

Many believe that real chemistry is harmful substances, it is dangerous to experiment with them, especially at home. There are many very exciting experiences that you can do with your child without harming your health. And these home chemical experiments will be no less exciting and instructive than those that come with explosions, pungent odors and puffs of smoke.

Some parents are also afraid to conduct chemical experiments at home due to their complexity or lack of necessary equipment and reagents. It turns out that you can get by with improvised means and those substances that every housewife has in the kitchen. You can buy them in the nearest household store or pharmacy. Test tubes for home chemical experiments can be replaced with pill bottles. Reagents can be stored in glass jars, e.g. baby food or mayonnaise.

It is worth remembering that the dishes with reagents must have a label with the inscription and be tightly closed. Sometimes the tubes need to be heated. In order not to hold it in your hands when heated and not get burned, you can build such a device using a clothespin or a piece of wire.

It is also necessary to allocate several steel and wooden spoons for mixing.

You can make a stand for holding test tubes yourself by drilling through holes in the bar.

To filter the resulting substances, you will need a paper filter. It is very easy to make it according to the diagram given here.

For children who do not yet go to school or are studying in elementary grades, setting up home chemical experiments with their parents will be a kind of game. Most likely, such a young researcher will not yet be able to explain some individual laws and reactions. However, perhaps just such an empirical way of discovering the surrounding world, nature, man, plants through experiments will lay the foundation for the study of natural sciences in the future. You can even arrange original competitions in the family - who will have the most successful experience and then demonstrate them at family holidays.

Regardless of the age of the child and his ability to read and write, I advise you to have a laboratory journal in which you can record experiments or sketch. A real chemist must write down a work plan, a list of reagents, sketches of instruments and describes the progress of work.

When you and your child just begin to study this science of substances and conduct home chemical experiments, the first thing to remember is safety.

For this you need to follow the following rules security:

2. It is better to allocate a separate table for conducting chemical experiments at home. If you do not have a separate table at home, then it is better to conduct experiments on a steel or iron tray or pallet.

3. It is necessary to get thin and thick gloves (they are sold in a pharmacy or hardware store).

4. For chemical experiments, it is best to buy a lab coat, but you can also use a thick apron instead of a dressing gown.

5. Laboratory glassware should not be used for food.

6. In home chemical experiments, there should be no cruelty to animals and violation of the ecological system. Acidic chemical waste should be neutralized with soda, and alkaline with acetic acid.

7. If you want to check the smell of a gas, liquid or reagent, never bring the vessel directly to your face, but, holding it at a certain distance, direct, waving your hand, the air above the vessel towards you and at the same time smell the air.

8. Always use small amounts of reagents in home experiments. Avoid leaving reagents in a container without an appropriate inscription (label) on the bottle, from which it should be clear what is in the bottle.

The study of chemistry should begin with simple chemical experiments at home, allowing the child to master the basic concepts. A series of experiments 1-3 allow you to get acquainted with the basic aggregate states of substances and the properties of water. To begin with, you can show a preschooler how sugar and salt dissolve in water, accompanying this with an explanation that water is a universal solvent and is a liquid. Sugar or salt are solids that dissolve in liquids.

Experience number 1 "Because - without water and neither here nor there"

Water is a liquid chemical substance composed of two elements as well as gases dissolved in it. Man also contains water. We know that where there is no water, there is no life. A person can live without food for about a month, and without water - only a few days.

Reagents and equipment: 2 test tubes, soda, citric acid, water

Experiment: Take two test tubes. Pour in equal amounts of baking soda and citric acid. Then pour water into one of the test tubes, and not into the other. In a test tube in which water was poured, carbon dioxide began to be released. In a test tube without water - nothing has changed

Discussion: This experiment explains the fact that many reactions and processes in living organisms are impossible without water, and water also accelerates many chemical reactions. Schoolchildren can be explained that an exchange reaction has taken place, as a result of which carbon dioxide has been released.

Experience number 2 "What is dissolved in tap water"

Reagents and equipment: clear glass, tap water

Experiment: Pour into a clear glass tap water and put it in a warm place for an hour. After an hour, you will see settled bubbles on the walls of the glass.

Discussion: Bubbles are nothing but gases dissolved in water. Gases dissolve better in cold water. As soon as the water becomes warm, the gases cease to dissolve and settle on the walls. A similar home chemical experiment also makes it possible to acquaint the child with the gaseous state of matter.

Experience No. 3 “What is dissolved in mineral water or water is a universal solvent”

Reagents and equipment: test tube, mineral water, candle, magnifying glass

Experiment: Pour mineral water into a test tube and slowly evaporate it over a candle flame (the experiment can be done on the stove in a saucepan, but the crystals will be less visible). As the water evaporates, small crystals will remain on the walls of the test tube, all of them of different shapes.

Discussion: Crystals are salts dissolved in mineral water. They have different shape and size, since each crystal has its own chemical formula. With a child who has already begun to study chemistry at school, you can read the label on mineral water, where its composition is indicated and write the formulas of the compounds contained in mineral water.

Experiment No. 4 "Filtration of water mixed with sand"

Reagents and equipment: 2 test tubes, funnel, paper filter, water, river sand

Experiment: Pour water into a test tube and dip a little river sand into it, mix. Then, according to the scheme described above, make a filter out of paper. Insert a dry, clean test tube into a rack. Slowly pour the sand/water mixture through a filter paper funnel. River sand will remain on the filter, and you will get clean water in a tripod tube.

Discussion: Chemical experience allows us to show that there are substances that do not dissolve in water, for example, river sand. The experience also introduces one of the methods of cleaning mixtures of substances from impurities. Here you can introduce the concepts of pure substances and mixtures, which are given in the 8th grade chemistry textbook. In this case, the mixture is sand with water, the pure substance is the filtrate, and river sand is the sediment.

The filtration process (described in Grade 8) is used here to separate a mixture of water and sand. To diversify learning this process, you can go a little deeper into the history of drinking water treatment.

Filtration processes were used as early as the 8th and 7th centuries BC. in the state of Urartu (now it is the territory of Armenia) for the purification of drinking water. Its inhabitants carried out the construction of a water supply system with the use of filters. Used as filters dense fabric and charcoal. Similar intertwined systems downpipes, clay channels equipped with filters were also on the territory of the ancient Nile among the ancient Egyptians, Greeks and Romans. Water was passed through such a filter several times through such a filter, eventually many times, eventually achieving best quality water.

One of the most interesting experiences is the growth of crystals. The experience is very clear and gives an idea of ​​many chemical and physical concepts.

Experience number 5 "Grow sugar crystals"

Reagents and equipment: two glasses of water; sugar - five glasses; wooden skewers; thin paper; pot; transparent cups; food coloring (the proportions of sugar and water can be reduced).

Experiment: The experiment should begin with the preparation of sugar syrup. We take a pan, pour 2 cups of water and 2.5 cups of sugar into it. We put on medium heat and, stirring, dissolve all the sugar. Pour the remaining 2.5 cups of sugar into the resulting syrup and cook until completely dissolved.

Now let's prepare the embryos of crystals - sticks. Scatter a small amount of sugar on a piece of paper, then dip the stick in the resulting syrup, and roll it in sugar.

We take the pieces of paper and pierce a hole in the middle with a skewer so that the piece of paper fits snugly against the skewer.

Then we pour the hot syrup into transparent glasses (it is important that the glasses are transparent - this way the process of crystal ripening will be more exciting and visual). The syrup must be hot or the crystals will not grow.

You can make colored sugar crystals. To do this, add a little food coloring to the resulting hot syrup and stir it.

The crystals will grow in different ways, some quickly and some may take longer. At the end of the experiment, the child can eat the resulting lollipops if he is not allergic to sweets.

If you do not have wooden skewers, then you can experiment with ordinary threads.

Discussion: A crystal is a solid state of matter. It has a certain shape and a certain number of faces due to the arrangement of its atoms. Crystalline substances are substances whose atoms are arranged regularly, so that they form a regular three-dimensional lattice, called a crystal. Row crystals chemical elements and their compounds have remarkable mechanical, electrical, magnetic and optical properties. For example, diamond is a natural crystal and the hardest and rarest mineral. Due to its exceptional hardness, diamond plays a huge role in technology. Diamond saws cut stones. There are three ways to form crystals: crystallization from a melt, from a solution, and from a gas phase. An example of crystallization from a melt is the formation of ice from water (after all, water is molten ice). An example of crystallization from solution in nature is the precipitation of hundreds of millions of tons of salt from sea ​​water. In this case, when growing crystals at home, we are dealing with the most common methods of artificial growing - crystallization from a solution. Sugar crystals grow from a saturated solution by slowly evaporating the solvent - water, or by slowly lowering the temperature.

The following experience allows you to get at home one of the most useful crystalline products for humans - crystalline iodine. Before conducting the experiment, I advise you to watch with your child a short film “The life of wonderful ideas. Smart iodine. The film gives an insight into the benefits of iodine and unusual story his discovery, which will be remembered for a long time by the young researcher. And it is interesting because the discoverer of iodine was an ordinary cat.

French scientist Bernard Courtois Napoleonic Wars noticed that in the products obtained from the ashes of seaweed, which were thrown onto the coast of France, there is some substance that corrodes iron and copper vessels. But neither Courtois himself nor his assistants knew how to isolate this substance from the ashes of algae. Chance helped speed up the discovery.

At his small saltpeter plant in Dijon, Courtois was going to conduct several experiments. There were vessels on the table, one of which contained an alcoholic tincture of seaweed, and the other a mixture of sulfuric acid and iron. On the shoulders of the scientist sat his beloved cat.

There was a knock on the door, and the frightened cat jumped down and ran away, brushing the flasks on the table with its tail. The vessels broke, the contents mixed, and suddenly a violent chemical reaction began. When a small cloud of vapors and gases settled, the surprised scientist saw some kind of crystalline coating on the objects and debris. Courtois began to explore it. Crystals to anyone before this unknown substance were called "iodine".

So a new element was discovered, and Bernard Courtois's domestic cat went down in history.

Experience No. 6 "Obtaining iodine crystals"

Reagents and equipment: tincture of pharmaceutical iodine, water, a glass or a cylinder, a napkin.

Experiment: We mix water with tincture of iodine in the proportion: 10 ml of iodine and 10 ml of water. And put everything in the refrigerator for 3 hours. During cooling, the iodine will precipitate at the bottom of the glass. We drain the liquid, take out the iodine precipitate and put it on a napkin. Squeeze with napkins until the iodine begins to crumble.

Discussion: This chemical experiment is called extraction or extraction of one component from another. In this case, the water extracts the iodine from the spirit lamp solution. Thus, the young researcher will repeat the experience of the cat Courtois without smoke and beating dishes.

Your child will already learn about the benefits of iodine for disinfecting wounds from the movie. Thus, you show that there is an inextricable link between chemistry and medicine. However, it turns out that iodine can be used as an indicator or analyzer of the content of another beneficial substance- starch. The following experience will introduce the young experimenter to a separate very useful chemistry - analytical.

Experience No. 7 "Iodine-indicator of starch content"

Reagents and equipment: fresh potatoes, pieces of banana, apple, bread, a glass of diluted starch, a glass of diluted iodine, a pipette.

Experiment: We cut the potatoes into two parts and drip diluted iodine on it - the potatoes turn blue. Then we drip a few drops of iodine into a glass of diluted starch. The liquid also turns blue.

We drip with a pipette iodine dissolved in water on an apple, banana, bread, in turn.

Watching:

The apple didn't turn blue at all. Banana - slightly blue. Bread - turned blue very much. This part of the experience shows the presence of starch in various foods.

Discussion: Starch, reacting with iodine, gives a blue color. This property gives us the ability to detect the presence of starch in various foods. Thus, iodine is, as it were, an indicator or analyzer of starch content.

As you know, starch can be converted into sugar, if you take an unripe apple and drop iodine, it will turn blue, since the apple is not yet ripe. As soon as the apple ripens, all the starch contained will turn into sugar and the apple does not turn blue at all when treated with iodine.

The following experience will be useful for children who have already started studying chemistry at school. It introduces concepts such as chemical reaction, compound reaction, and qualitative reaction.

Experiment No. 8 "Flame coloring or compound reaction"

Reagents and equipment: tweezers, table salt, spirit lamp

Experiment: Take with tweezers a few crystals of coarse salt table salt. Let's hold them over the flame of the burner. The flame will turn yellow.

Discussion: This experiment makes it possible to carry out a chemical combustion reaction, which is an example of a compound reaction. Due to the presence of sodium in the composition of table salt, during combustion, it reacts with oxygen. As a result, a new substance is formed - sodium oxide. The appearance of a yellow flame indicates that the reaction has passed. Similar reactions are qualitative reactions for compounds containing sodium, that is, it can be used to determine whether a substance contains sodium or not.