Question-answer No. 20
Added: 12/05/2013
Since time immemorial, almost immediately after the advent of writing, people began to think about the possibilities of maintaining the secrecy of correspondence. Of course the best way to solve such problems steel invisible ink. Secret writing, applied to paper using special substances, made it possible to hide a lot of different secrets. A meaningless note, visible to others and written over the disappeared words, carefully kept its secret until a “craftsman” appeared who was able to read the text hidden between the lines.
Today, invisible ink, also called sympathetic ink, can be made independently at home. This unique invention can be used for various purposes, but in most cases, it is the basis for all kinds of comic pranks. To mask the notes as much as possible with invisible ink, in order to hide the slightest hint of their presence, you can write something else on top of such colorless text, for example, a poem by Pushkin.
There are several recipes for making sympathetic ink:
First way
In former times, liquids were used as disappearing ink, which after drying did not leave the slightest trace on paper: white wine, beer, milk. To develop a recording made from the above “ink”, you will need ordinary ashes. To enhance the effect, before treating with ash, the paper can be slightly moistened with breath.
Second way
Very good results can be achieved using rutabaga juice, Apple juice, onion juice, citric acid. To manifest messages written in such invisible ink, it is enough to hold a sheet of paper at a distance of ten centimeters from the fire. If you don’t want to come into contact with fire, you can simply hold the paper under a hot iron.
Third way
Starch can also be used to make invisible ink. To read the inscription, the paper should be treated with a weak iodine solution. As you know, under the influence of iodine starch turns blue.
Fourth method
Regular washing powder can also be a good base for creating colorless ink. To read the inscription, just place it under the source ultraviolet radiation. As a rule, such lamps are used in nightclubs, solariums, and devices designed to detect counterfeit banknotes.
Fifth method
Often in extreme conditions The role of ink was performed by ordinary saliva. A weak ink solution was used for development.
Sixth method
If you use a syringe to inject a goose feather a small amount of colorless phenolphthalein indicator, you will get a good improvised pen. To develop the recording she made, you need to use a swab soaked in any alkali (sodium hydroxide or potassium hydroxide). The letters will instantly take on a crimson color.
Seventh method
You can write colorless messages with rice water. To develop a recording, it is enough to treat it with a weak alcohol solution of iodine. As a result, the letters turn blue due to the starch contained in the rice.
Eighth method
You can make notes on paper using a highly concentrated solution of cobalt chloride. This text appears beautiful blue when heated. Moreover, such a record can subsequently be “made” to disappear again. To do this, just breathe on it or hold it over the steam.
Ninth method
Dextrin and iodine will also help create disappearing ink. Dextrin is a substance obtained by heating starch. Add 3 grams of dextrin to 30 ml of iodine and pass through filter paper. Use the resulting blue ink to write some text. After a couple of days, the recording will disappear without a trace, and it will be impossible to restore it, thanks to the volatility of iodine.
Invisible ink is a collective name for compounds that, once applied to paper, are invisible to the naked eye and appear after treatment with reagents or changes in temperature. Similar writing instruments were used in diplomatic correspondence and intelligence.
Below are simple recipes, available to all novice spies and conspirators. Ingredients needed can be found in every kitchen, found in any chemical kit, bought at the nearest pharmacy.
Read also:
So, what can we do with our own hands at home? And a lot of things!
Pour some milk into a glass. We write the secret message with a thin brush or a cotton swab; in extreme cases, a toothpick, a feather, or an ordinary sliver will do.
Having entrusted information to a piece of paper, it should dry thoroughly, preferably without resorting to direct sunlight: Ultraviolet light is harmful to spy secrets. After making sure that the milk is dry and invisible on the paper sheet, you can send it to your accomplice.
You can make text visible by heating the paper. In our hasty times, this is usually done using an iron.
Sometimes a secret document is put in the oven, heated near a light bulb, and if the message is not so urgent, it can be placed on a warm radiator. True fans of spy traditions use a candle flame and nothing more.
After cutting the lemon, squeeze the juice into a cup, add a few drops of water, and stir. We can use a fresh apple in a similar way: after grinding the fruit on a fine grater, we squeeze out the juice we need. If you don't have an apple, you can take an onion.
You will have to experiment a little with the ratio of juice and water: if the concentration of acid in the composition is too high, the fresh inscription will stand out against the background of the paper and will no longer be secret, otherwise the developed text will turn out unclear.
The time spent is repaid by the ease of use of the resulting solution: if you are too lazy to fiddle with brushes and sticks, you can pour it into a fountain pen. After writing, dry. Develop by heating the paper.
The ancient Chinese once again confirmed their status as the wisest people on the planet by combining the exciting and therefore energy-consuming process of writing a secret message with cooking.
Thick rice porridge was cooked in such a way that some of the liquid remained on the surface without being absorbed into the rice. Dipping a brush into this liquid, they wrote a message. After completing the work, the narrow-eyed spy wiped the sweat from his forehead, left the paper to dry, and, raising his head, a short prayer Buddha, began to eat.
The “delicious” recipe for invisible ink did not remain a Chinese monopoly for long; it was soon borrowed by scouts from the islands lying in the east.
So the young spy, devouring another portion of porridge left after a secret writing session to the delight of his mother, can rightfully consider himself a successor to the ninja traditions.
In ancient times, the “rice” inscription was developed by heating the paper. But the white-faced devils came up with an innovation here too: they began to cover the leaf with iodine. The text now appears more clearly.
Time-honored invisible ink recipes are listed. Let's move on to more modern methods in the style of James Bond.
There are other options for making ink. We have a dime a dozen craftsmen!
Mix water and soda in equal proportions. We apply the text to paper and dry it in the shade. It is curious that the usual heating for developing text will not help, you should resort to help grape juice. By applying the juice with a brush over the entire surface of the leaf, we can read the message.
Add one part water to two parts, stirring, heat the resulting mixture over low heat, let it cool. Apply the text with a toothpick, match, or any wooden stick.
For manifestation cover the paper with iodine. The leaf will become tender purple tint. The inscription will be dark purple.
Add a couple of pinches copper sulfate into a glass of water, stir thoroughly until the crystals are completely dissolved. Apply the inscription with a brush, a cotton swab or a fountain pen filled with a solution. Dry in the shade. For manifestation hold the leaf for some time over the container with ammonia , under the influence of the vapors of which the text will turn blue-green.
We dilute regular bleaching washing powder with water, make an inscription, and dry it in the shade. The text can only be seen with an ultraviolet flashlight.
Dissolve in water a regular aspirin tablet, and invisible ink is ready. We apply the text and dry it. You can read the message after treating the paper with a solution of iron salts, which are found in powder form in almost every chemical kit.
Recipes for making invisible ink. Ways of their manifestation.
Secret writing appeared in the first century BC. These were the secret records of the pharaohs. Since then, a lot has changed in secret writing. They began to use not only plant juice and milk for this, but also specially developed chemical inks. Basically, this type of secret letter is aimed at diplomatic negotiations or secret correspondence.
Sympathetic ink is a special composition that, when applied to paper under normal conditions, becomes invisible. Under certain conditions, entries appear. This can be either treatment with reagents or a change in temperature. Often such ink will appear when heated. Initially, this method was used for secret correspondence. Now this is a kind of shorthand method.
Such ink is quite easy to make at home. Such experiments will be interesting for children. First of all, you need to find out what you are going to make the ink from. There are many components and options.
Ink options:
This ink is developed by salts that contain iron. This can be bertholet salt or iron sulfate. The recipe for making ink is simple.
Instructions:
Oddly enough, invisible ink can be made from lemon juice.
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Lettering produced in this way can be viewed using UV light. A fluorescent lamp or flashlight will do.
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This ink was used by the ancient Chinese to write inscriptions.
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This is the most good recipe, since the inscriptions after development become bright and saturated.
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A simple method from a product that is found in almost every refrigerator.
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To apply beeches, a concentrated solution is used.
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This is a special ink because it is visible at first, but after 1-2 days it completely disappears.
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This method was used in the Middle Ages. The method was also popular among inquisitors.
Instructions:
Milk, cobalt chloride and lemon juice react to heating.
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For this you can use ballpoint pen or feather. With a feather pen everything is simple. You need to pour one of the secret solutions into the ink compartment and feel free to start writing.
Instructions for making a pen with invisible ink:
How to make a pen with invisible ink? How to refill a pen with invisible ink As you can see, with the help of simple manipulations you can make invisible ink. This will amuse your children.
Invisible ink is a solution for writing on paper. Initially, the inscription cannot be seen until some chemical action is applied to the ink. There are many different recipes for invisible ink, but most of them still leave marks on the paper that can be seen with the naked eye. Today we will prepare real spy invisible ink that cannot be noticed before development.
To make invisible ink we need:
Stirring constantly, add baking soda to warm water until it stops dissolving. Dip a cotton swab into the solution, squeeze it a little to remove excess liquid and write your secret message. It's that simple!
We prepare a weak, slightly blue solution of copper sulfate and write it on paper with a stick, dipping it into it. After drying, the inscription is almost invisible. To develop the inscription, you need to hold a sheet of paper over an open bottle of ammonia. When it appears, the inscription is blue-green. This is an ammonia complex of copper obtained as a result of a chemical reaction.
We will need quite a bit (on the tip of a knife) of ammonium chloride (ammonia). Add a teaspoon of water to it. Ready! The resulting solution can be used for secret writing. Invisible ink can also be revealed using heat.
Perhaps the most effective recipe for invisible ink includes cobalt chloride and water. What’s remarkable about it is that after drying on paper, the solution is almost invisible to the naked eye. Highly dilute cobalt chloride forms a pale-pale crystalline hydrate Pink colour, which visually completely merges with the white sheet. But after heating, bright blue letters appear on the paper! However, if the paper sheet is moistened, for example, by holding it over steam, the letters will disappear again, because crystal hydrate is formed.
Probably not in the kitchen anymore, but on paper. Let's do it DIY invisible ink.
It's great to use developing liquids for secret drawings, treasure maps, secret letters.
The first method is perhaps the most famous.
Vlad was unable to write a letter with a brush; for now he can only manage it with a pen or pencil. I received this message one morning 
Therefore, they painted a landscape with milk, dipping a brush into it. After drying, we ironed it and the writing became visible.
This happened because the protein contained in milk burns at a much lower temperature than paper. Therefore, when heated, the paper remains white, but the milk already darkens.
Another way of chemically classifying messages iswrite with lemon juice.After drying, wipe with cotton wool and iodine. In place of the letters there will be bright spots. This is what they recommend in the book, but in practice it was hard to see. The result is a drawing - Africans in night Africa)))
This is a dad with his son and a truck on a string. We were not at all upset when we saw this result. Our grandmother had a lot of fun with her creation. And then Vladik and his grandmother drew a joint masterpiece.
Grandpa turned out to be very similar! By the way, I read that felt-tip pens are also indicators and react differently to acids and alkalis. But during our experiment, the stains from the felt-tip pens blurred equally, whether from a solution of soda or from vinegar.
But the Chinese emperor Qing Shi Huangdi (249-206 BC), during whose reign the Great Chinese Wall, used thick rice water for his secret letters, which, after drying the written hieroglyphs, does not leave any visible traces. If such a letter is slightly moistened with a weak alcohol solution iodine, then blue letters appear. And the emperor used a brown decoction to develop letters seaweed, apparently containing iodine.
And what creative continuation of the experiments would you offer your child? Share your ideas in the comments and send photos of experiments and experiments from your home laboratory. Thank you for reading our notes and sharing them on in social networks. We're committed to making science fun for you.
Happy experimenting! Science is fun!
