With the cold, when you are in natural conditions far from home, you can and should fight. Moreover, now there are many modern and technologically advanced portable devices on the market, individual heating pads. various types and types, compact gas heaters and so on, the operation of which is based on various physical and chemical processes.

According to statistics, from 10 to 15% of people who died in natural conditions became victims. Even the warmest clothes negative temperatures air, capable of maintaining a positive heat balance the human body for only a very limited time. Sooner or later, the heat loss will be greater than the heat production and the cooling of the body will begin. Prolonged exposure to cold is dangerous. It paralyzes the will and dulls the instinct of self-preservation. This can eventually lead to at least serious problems with health, or at most - to death.

Disposable chemical heating pads and thermal packs for heating in the field.

The cheapest and available means individual heating are various disposable chemical heating pads (thermal packs) for hands and feet. Heat in such heating pads is usually generated as a result of a chemical reaction between the contents of the package itself and oxygen. Such heating pads are very easy to use, sometimes it will be enough to start the process of heat release by removing it from the package. Working temperature, depending on the purpose of a disposable heating pad - from plus 40 to 60 degrees Celsius. Operating time - from 4 hours or more.

The design of some disposable chemical heaters allows you to temporarily stop the process of heat release from it. To do this, it is enough to stop the access of oxygen to its active content and the reaction stops. Disposable chemical heating pads will be convenient autonomous sources of heat for fishermen, tourists, hunters and the military. They can be put in shoes, in gloves, in inner pockets of clothes, to heat equipment (photo and video cameras) when working in the cold, etc.

Reusable salt heaters for heating in the field.

Reusable salt heaters is a sealed container made of dense material, which is filled with a supersaturated saline solution. The principle of operation is based on the effect of heat release when the phase state of materials changes. Salt heating pad can have almost any shape and size. So, for example, a saline foot warmer can be in the form of an insole.

Inside the heater there is an applicator (stick or circle), with the help of which it is launched. The operating temperature of salt heaters is from 50 degrees and above. The operating time depends on the size of the heater itself and the ambient temperature - from 2 hours or more. After the end of the work cycle, salt heaters are put into working condition by placing them in boiling water for a while, after which it is again ready for reuse.

reusable catalytic heaters for heating in the field.

In addition to disposable chemical heaters, there are reusable pocket catalytic heaters. The principle of their operation is based on the catalytic flameless oxidation of alcohol or gasoline vapors, which is accompanied by the release of heat. Platinum serves as a catalyst in such heating pads. A striking example— classic pocket catalytic gasoline heating pad Zippo Hand Warmer. More details about it are written on our website.

Prevention of hypothermia in cold weather.

In cold weather, you should try to adhere to the following simple rules.

1. Generate heat.

Eat often, but little by little, and high-calorie foods. When food is taken frequently and in small portions, this increases the overall metabolic rate of the body, since more calories are consumed in the process of digestion. This in turn leads to the production more internal heat.

If necessary.

- Do warm-up exercises.
- Make fire and use reflective surfaces.
- If possible, always be located with south side to receive solar heat to the maximum.
- Drink warm or hot liquids with sweets or sugar dissolved in them.

2. Reduce heat loss.

- Wear appropriate clothing and footwear for the weather.
- Especially insulate the head and neck.
- As soon as possible, immediately change from wet clothes to dry.
- Find or make a protective cover or shelter.
– Isolate the body from cold surfaces as much as possible.
- Avoid alcohol completely.

Chemistry often works wonders. This time we present to your attention another homemade product, based on the chemistry and properties of certain substances. We are talking about the manufacture of a chemical heating pad, which in its properties is in no way inferior to the classical one.

You can watch the process of making a chemical heating pad by watching the author's video

What do we need:
- copper sulfate;
- the spoon;
- food foil;
- kitchen salt;
- plastic bottle;
- wooden barbecue skewer;
- glue gun.

At the beginning of the video, the author uses vitriol crushed in a coffee grinder. According to him, he does this solely for demonstration, since vitriol crystals crack when heated. As for the properties of this substance, one important property is the transformation of vitriol into a gray powder when heated. Also, when heated, vitriol completely loses water.

It should be added to the resulting powder of water as it begins to heat up. Heating in this case accelerates the onset of the reaction. This property of vitriol is used by the author to obtain a chemical heating pad. Let's get started.

Take a piece of food foil. The author uses a piece 28 cm wide and 20 cm long.

Fold the foil in half.

After that, wrap it in foil in a tube.

We take a wooden skewer and glue it into the bottle cap with a glue gun.

Now we mix the main components of the burner, that is, salt and gray vitriol powder. The ratio of salt and vitriol is 1:2.

Pour salt and vitriol into a bottle.

We add water.

We close the bottle cap, after which we observe that the mixture quickly warms up to room temperature due to the dissolution of anhydrous blue vitriol.

We put a foil tube on a skewer to evenly heat the liquid in a plastic bottle.

In the process of a chemical reaction, hydrogen and heat will be released, which will accelerate it. In this case, it is necessary to constantly bleed hydrogen and control the pressure in the bottle by slightly opening and closing the cap, as well as periodically shaking it.

Some time later aluminium foil will begin to dissolve, and copper will be released from the solution.

The end of the reaction can be recognized by the end of gas evolution for a minute.

The author's test showed that in this way the water is heated up to 50 degrees Celsius. Again, according to the author, you can boil water, but a plastic bottle will not withstand this. This can be done in a glass cup. Such a heating pad can be used to warm stiff fingers on a fishing trip or at home. Army flameless food heaters work on this principle.

Gerasimenko Elena

The work "Thermochemical reactions in the creation of a chemical heating pad" considers practical use theoretical material about chemical reactions.

The choice of the problem of interest is substantiated. The ability to create a "chemical heating pad" in everyday life from inexpensive improvised materials can be very useful in extreme environmental conditions.

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Municipal general education state-financed organization average
secondary school №19 MO Korenovskiy district

Scientific and practical conference of schoolchildren "Evrika"

"Thermochemical reactions in the creation
chemical heating pad "

Completed by a student of 11 A class MOBU secondary school No. 19MO Korenovskiy district

Gerasimenko Elena Mikhailovna Head teacher of chemistry Bobrovskaya L.F.

Korenovsk

year 2014

annotation

The work "Thermochemical reactions in the creation of a chemical heating pad" considers the practical application of theoretical material on chemical reactions.

The choice of the problem of interest is substantiated. The ability to create a "chemical heating pad" in everyday life from inexpensive improvised materials can be very useful in extreme environmental conditions.

Accessibility analyzed Supplies. The thermal effects of reactions are calculated from the standard enthalpies of formation of substances.

In the work, the student conducted experiments using the new laboratory equipment Mishab, on the basis of which she calculated the ash effects of reactions and established the most effective reactions.

The result of the work was formulated recipes and recommendations for the creation of "chemical heating pads" in an understandable and accessible form.

The work has practical application and deserves attention.

Introduction.

In the cold season, people whose activities are related to the implementation of certain
tasks on the street, there is always a desire to warm up. But it's not always there
conditions. The problem can be solved by using heating pads.

In my work, I decided to investigate the problem of creating a chemical heating pad. The heating pad can be reusable. For reusable "warmers" crystalline salts are best suited, which can be stored supercooled for a long time. On sale there are similar heating pads filled with sodium acetate crystalline hydrate CH3C0 (Za-ZH20. This salt melts in its own water of crystallization at 58 ° C. Salt placed in plastic bag, melted in boiling water and then the melt can be cooled to room temperature and below without crystallization (supercooling). Then it is enough to crush the bag - and crystallization begins with the release of heat. This process can be repeated many times."

I was more interested in the possibility of creating a real chemical heater, which works due to the exothermic reactions taking place in it. Such heating pads are disposable, it is convenient, because after use it can be thrown away or disposed of.

I managed to find several recipes for such heating pads. The goal of my work was to choose the most convenient, reliable, affordable, cheap and effective prescription, testing and testing it in practice.

. .) ^ > * 1 3

In the course of my work, I studied the theory of thermochemical reactions, calculated the thermal effect of the selected reactions, and conducted experiments with the selection of different recipes.

Study plan

In the study of chemistry, we get acquainted with thermochemical reactions that proceed with the absorption or release of heat. The energy stored in substances in the form of chemical bonds is released when new substances are formed. AT chemical production"This energy is used to heat reagents or to produce vapors, to heat water.

Thermal effects of chemical reactions are necessary for many technical calculations.

The effect of some exothermic reactions can be used to create a personalized portable heater.

The aim of the work was to investigate some chemical reactions to create a thermochemical heating pad. For this, some experiments were carried out using the most available reagents.

I want to investigate the problem of using the energy of chemical reactions in miniature individual heating systems "heaters". For this it is necessary:

1. Study the issue and establish whether there are such heating pads;
2. Choose the most suitable reactions for creating chemical heating pads;
3. Choose the most efficient reactions in terms of calorific value in the course of a chemical comparative experiment;
4. Choose the most convenient form for filling and application.

1. thermochemical reactions.

Thermochemistry -- a section of chemical thermodynamics, whose task is to determine and study the thermal effects of reactions, as well as to establish their relationship with various physicochemical parameters. Another of the problems of thermochemistry is the measurement of the heat capacities of substances and the determination of their heats of phase transitions.

Thermochemical equations

Thermochemical reaction equations are equations in which near the symbols chemical compounds the states of aggregation of these compounds or the crystallographic modification are indicated, and the numerical values ​​of thermal effects are indicated on the right side of the equation.

The most important quantity in thermochemistry is the standard heat of formation (standard enthalpy of formation). Standard heat (enthalpy) of formation complex substance called the thermal effect (change in standard enthalpy) of the reaction of formation of one mole of this substance from simple substances in standard condition. The standard enthalpy of formation of simple substances in this case is taken equal to zero.

AT thermochemical equations it is necessary to indicate the aggregate states of substances using letter indices, and the heat effect of the reaction (NR) should be recorded separately, separated by commas. For example, the thermochemical equation

4Sh 3 (g) + 30 2 (g) -+ 2H 2 (g) + 6H 2 0 (g), DN = -1531 kJ

shows that this chemical reaction is accompanied by the release of 1531 kJ of heat, at a pressure of 101 kPa, and refers to the number of moles of each of the substances that corresponds to the stoichiometric coefficient in the reaction equation.

In thermochemistry, equations are also used in which the thermal effect is attributed to one mole of the formed substance, using fractional coefficients if necessary.

Hess' law

At the core thermochemical calculations Hess's law lies: The thermal effect (DH) of a chemical reaction (at constant P and T) depends on the nature and physical state of the starting materials and reaction products and does not depend on the path of its occurrence.

Consequences from the law of Hess:

1. The thermal effects of the direct and reverse reactions are equal in magnitude and opposite in sign.
2. The thermal effect of a chemical reaction (DN) is equal to the difference between the sum of the enthalpies of formation of the reaction products and the sum of the enthalpies of formation of the starting substances, taken taking into account the coefficients in the reaction equation (that is, multiplied by them)."

Hess' law can be written as the following mathematical expression:

∆ N in \u003d ∑ (∆ N 0 reaction products) - ∑(∆ Н 0 reagents )

Using data on standard enthalpies, I will calculate the thermal effect of reactions for chemical heaters.

1. Recipes for chemical heating pads.

1. compound : One of the simplest chemical heating pads contains calcium oxide CaO ( quicklime), which reacts with water to form calcium hydroxide:

CaO + H 2 0 \u003d Ca (OH) 2.

The reaction is accompanied by heat release. The temperature of the heating pad can reach 70-80°C.

1. compound : In a chemical heating pad of another type, the interaction of metals (in the form of chips) and salts is used. A completely dry mixture of iron (Re) shavings with copper salts (for example, CuCl 2 ) can be stored for quite a long time, and when water is added, the temperature immediately rises to almost 100 ° C due to the reaction:

F e + CuC1 2 = F eC1 2 + C.

At the same time, a heating pad in which copper chloride CuCl 2 turns into ferric chloride F eC1 2 , retains heat for about ten hours.

1. compound : Equipment: aluminum wire, copper sulfate, table salt, sawdust, water.

2A1 + ZSi S 0 4 - A1 2 (S 0 4 ) 3 + ZSi.

Sodium chloride is added to intensify the process, chloride ions accelerate and facilitate the reaction with aluminum. Against the background of this reaction, there is probably also a reaction of aluminum with water, such as

2А1 + 4Н 2 0 => 2А10(0Н) + ЗН 2 .

1. compound : For the manufacture of a chemical heating pad, it is better to use copper chloride powder and aluminum filings. Mix 5-6 g of copper chloride with the same amount of aluminum filings by weight and add 5-6 tablespoons of well-dried sawdust. Pour the resulting mixture into a plastic bag. The heating pad begins to act when 30-40 ml of water is poured into the bag. Copper chloride, dissolving in water, reacts with aluminum:

3CiC12+2A1=2A1C13+3Ci.

The reaction is accompanied by the release of heat. The sawdust acts as a "thinner" to keep the reaction from going too fast.

1. compound : a mixture of potassium permanganate and iron powder in a steel cylinder. Invented by the Japanese during World War II. Weighed about two hundred grams. It was worth adding a little water, and this mixture began to warm up. The heating pad worked up to 20-30 hours, and it outdoor temperature did not exceed sixty degrees, that is, it could not burn the skin. One such heating pad was enough to warm an adult.
2. compound : A flat polypropylene bag that oxidizes iron dust with air oxygen to form rust and generate heat. The composition of the mixture also includes water, salt (works as a catalyst), Activated carbon(evenly distributes heat), vermiculite (serves as a heat accumulator) and cellulose (filler). The heating pad is disposable, starts working after opening the sealed package (to provide access to oxygen) and is able to provide heat for several hours.
3. compound : You can still add oxalic acid or citric acid(crystal hydrates), which increases the heat output. Such heaters allow you to get a temperature of 100 to 300 ° C. To start them, a small amount of water is introduced into the reaction mixture of calcium oxide and oxalic acid crystalline hydrate; in the process of reaction with calcium oxide, the water released during neutralization will react.

. - « ■ (IV / 1 V *

CaO + H20 \u003d Ca (OH) 2 + 10.6 kcal

Ca (OH) 2 + H2C204 * 2H20 \u003d CaC204 + 4H20 + 31 kcal

1. compound: A MORE EFFICIENT composition of chemical heaters is a mixture of iron filings, potassium permanganate, coal and sand. Coal and sand serve as reaction retarders. Heat is released as a result of adding water to said mixture.

The resulting reaction when water is added to the mixture will be:

4Ee + 2H20 + 302 = 2(Ee203"H20) + 390.4 kcal

Such a mixture, placed in the body, allows you to maintain a temperature of 100 ° C for 10-12 hours. An individual heating pad of this type is a rubberized bag filled with the specified composition with a neck for pouring water.

1. compound: And the best disposable heating pad (precisely a chemical heating pad, because reusable has nothing to do with chemistry) is a mixture of iron and copper filings with salt. Filled with water and starts to heat up.

Substance and state	DN 298 kJ/mol	Substance and state	DN° 2 98 kJ/mol
Ca09(cr)	635,1	А12(50)3(cr)	3441,8
H 2 0 (w)	285,83	А1С13(cr)	704,2
Ca (OH) 2 (cr)	985,1	(Ee203*H20)
CUS(cr)	205,85	Si504*5N 2 0(cr)	2279,4
PeC1 2 (cr)	341,7	Su$04(cr)	770,9

CaO + H 2 0 \u003d Ca (OH) 2

DN ° 298 \u003d DN ° 2 98 (Ca (OH) 2) - (DN 0 2 98 (CaO) + DN 0 2 9 8 (H 2 O)) = -985.1 - (-635.1-285.83) = -64.17 kJ / mol

Her + CuC1 2 = GeC1 2 + Cu

DN ° 298 \u003d DN 0 2 98 (ReС1 2) - DN ° 29 8 (СuС1 2 ) \u003d -341.7 + 205.85 \u003d 135.85 kJ / mol2A1 + 3Cu804 = A12(80)3 + 3Cu

DN ° 298 = DN 0 298 (A12 (8O) 3) - DN ° 298 (Cu804)*3= -3441.8 -(3*(- 770.9))=-1129.12A1 + 4H20 => 2AYU(OH) + ZN2 DN ° 298 = DN ° 2 98 (A10 (0H)) * 2 - DN ° 298 (N20) * 4 =

3CiC12+2A1=2A1C13+3Ci.

DN° 298 = DN° 298 (А1С13)*2 - DN°298(СuС1 2 )*3-585,2 *2 - (-205,85 *3) = - 552,45

4. Experiment.

For determination of practical outputheat of different reactions, I will conduct an experiment. AT

under the same conditions I observe heatcreative ability of mixtures and cooling time.

	Composition of the mixture	Temperature change
		initial	through	through	through	through	through	through
			minutes	minutes	minutes	minutes	minutes	minutes
	CaO + H 2 0	“20th		"20 e	“20th	“20th	“20th	20°
	Re + CuC1 2	20th	55°		100°	“68 e	37° ■	25°
	A1(pore) + CuC1 2	20°	100°	95°	“95 e	oo
	A1(pr)+Si804+NaS1	20°	“30th”	35°	"32 e	28°	^22°	20°

Conclusion, the highest heat output is observed when aluminum interacts with

copper chloride. Based on this mixture, the heating pad will work most efficiently, but you need to choose the proportions of the reagents

5.0 determination of the heat effect of the reaction 5 grams of CuC were added to 50 g of water l 2 *2 H 0 and some aluminum powder. By

change in water temperature e la thermal effect of the reaction.

b. Chemical heating pad recipe

To create chemical Greeks, you need to prepare a mixture.

For 1 tablespoon of blue vitriol, take 1 tablespoon of salt and add 1 teaspoon of aluminum powder. The temperature of the heating pad will rise to 100° and

gradually decrease.

Conclusion.

Thanks to the experiments, it was concluded that the most optimal for creating a thermochemical heating pad is the reaction of displacement of metal from salt by a stronger metal.

The main task practical work was to create a portable heater from available reagents, which will be used in the cold season and serve as a heating pad in field conditions.

To create a heating pad, some reactions were carried out:

1. .Interaction of copper chloride (||) with aluminum

A mixture of copper chloride, coal and sawdust is prepared. Sprinkled with aluminum powder. Added water. Using the device, the maximum heating temperature (100 ° s) and the time for lowering the temperature to 22 ° s (approximately 1.5 -2 hours) were measured

1. .Interaction of copper chloride (||) with iron

I prepared a mixture of copper chloride (dry), coal and sawdust. Sprinkled with iron powder. Added water. Using the device, I found out that substances interact poorly. The temperature rose from 25°C to 35°C, and lasted no more than 40 minutes.

1. lime slaking

Calcium oxide was taken for the reaction. Added water. The reaction did not occur (most likely due to long-term storage, calcium oxide is converted to calcium carbonate).

Based on the experiments, it was concluded that to create a heating pad, the most optimal reaction is the displacement of metal salts by a more active metal.

It turned out from experience that many exothermic reactions occur aggressively, with rapid gas evolution, with a small thermal effect and are not suitable for creating a thermochemical heating pad.

Bibliography:

FindPatent.RU2012-2013

Terms of Use!

• Do not put the heating pad in the microwave
• When restoring the heating pad, always use a cloth or towel.
• When removing the heating pad from boiling water, avoid sharp objects.
• If after use the heating pad is in a solid state, do not attempt to fold it to place it in a saucepan, this may cause the package to burst. First boil one side of the heating pad, then turn over and boil the other side so that it becomes soft, and then you can completely lower the heating pad into the pan.
• When punctured, the heating pad self-crystallizes and becomes unusable.
• When the heating pad is cooled down to - 8 Cº, the solution self-crystallizes. To restore the heating pad, it must first be warmed to room temperature, and then boiled.
• If the heating pad you purchased is in a solid state, it means that it has self-crystallized due to accidental strong. shock or low temperature during transportation. This is a natural phenomenon - if it occurs, then boil the heating pad before the first use.
• To warm the body for people with sensitive skin and children under 3 years old, it is recommended to wrap the heating pad with a cloth.
• During the operation of the heating pad, crystals in the form of snowflakes may appear in the solution. The presence of crystals does not affect the normal operation of the heater and is not a defect of the salt heater.
• The insole warmers are not designed to be used as walking insoles. The maximum static load on the heaters must not exceed 90 kg.
• In case of contact with the solution on the mucous membranes of the eyes, nose, mouth, rinse them with warm water.
• Store at room temperature. Avoid direct sunlight.
• Before using the salt heating pad in medicinal purposes consult with a specialist.

Heating pads are versatile heating tools that are used in various fields life. They are used both for therapeutic procedures for the purpose of warming up and for warming up. separate parts bodies in winter frosts. The most high-quality and harmless warming is carried out in the process of using salt heaters. Often these are reusable, less often disposable plastic bags filled with saline, which is the heat-generating component.

How does a salt heater work

The work of the salt heater is based on the chemical process of the interaction of salt concentrate with an aluminum spring and other components that are not toxic and do not have a negative effect on the body. A chemical reaction is accompanied by an immediate release of heat. It should be noted that the heat obtained during the interaction of the reagents remains for a long time. The duration of maintaining the temperature depends on the concentration of the composition in the compress and the volume of the package. Detailed information is indicated on the heating pad itself.

Indications for the use of a salt heating pad

As you know, heating pads are designed not only to warm individual parts of the body in cold weather. Often they are used in therapeutic purposes to relieve inflammation, warm during colds, to expand blood vessels, etc. It is worth noting that these thermal packs can even be used for cosmetic purposes.

The device has the following indications regarding the treatment and prevention of diseases:

• abundant local inflammatory processes;
• in the first hours after mechanical damage (sprains, bruises, etc., if you use a salt heater as a cooling element);
• bleeding from the nasal cavity;
• as part of postoperative rehabilitation;
• with meningitis, sinusitis, bronchitis and other diseases.

Application for newborns

Salt heating pad is a “magic” remedy that allows you to save your baby from colic. In order to use it for an infant, you should consult a pediatrician regarding the method of applying a thermo-compress. Often, so that the temperature of the heating pad is not too hot for the baby, it is wrapped in a cloth or towel from natural material and applied to the baby's tummy. Such a tool is easy to use and can be bought at a pharmacy - it is sold almost everywhere.

Salt heating instructions

A product such as a salt heater is a versatile and necessary appliance in every home. To use the thermal compress, you must activate it, after which a chemical reaction begins inside the heating pad with the release of heat. The heating process is carried out very quickly, in about 30 seconds, reaching optimal temperature, equal to 52-55 degrees. During heating, the liquid inside the plastic bag changes color and becomes solid. For this reason, it is necessary to immediately apply a thermal compress to the area to be warmed so that the package takes on the curves of the body with local interaction.

How to turn on the heating pad and how long the heat lasts

To activate the heating pad, you should squeeze it. In most cases, if the device is designed to withstand the load, for example, a warmer insole, a collar warmer, or a back warmer, then the compression process is carried out by itself. After the pressure in the plastic bag has increased, the reaction begins with the release of heat.

How to restore the device

The a heating element quite popular due to the fact that for its restoration, recharging does not require any additional tools or complex processes. All that is needed in order for the heating pad to start producing heat again is to boil it in ordinary water. This procedure is carried out for 20 minutes, after which the element is again able to perform its direct functions.

Overview of salt heaters with a photo

To date, there is a huge range of salt heaters that are used in different areas life and for various purposes. Below is a list of the most popular products that are in the greatest demand.

Warmer "Super ENT" for the nose

This is reusable heating pad, which is designed specifically for the treatment of ENT diseases, including: sinusitis, frontal sinusitis, rhinitis, etc. Thanks to convenient form and a small weight, which is equal to 130 grams, it can be easily applied to the nose area, while the process of warming the sinuses will not cause any discomfort. For the manufacture of the product are used only environmental materials that are non-toxic. Inside, the heating pad contains saline solution, which is widely used in various areas of life. The heating temperature is 53 degrees, and this indicator can remain unchanged for 85 minutes.

"Insole" for feet

This is a special insole, which is designed to fit inside shoes for contact warming of the feet. This option is perfect for lovers winter views sports, including fishing, hunting, snowboarding, etc. The heater contains components such as water, activated carbon, salt, cellulose and iron, which makes the device completely non-toxic. average temperature insoles is approximately 35 degrees, the maximum temperature is 39 degrees. The heat generated by the device is retained for five hours or more.

"Matrasik" for the back and joints

This heating pad is a small plastic bag filled with concentrated saline solution. Its dimensions are approximately 29 cm long and 18 cm wide, which makes the heating tool convenient fixture which is easy to use in household purposes. Maximum temperature heating pad is 55 degrees. To activate the process of salt crystallization with heat release, it is only necessary to slightly compress the spring immersed in the liquid. To use the tool again, it should be immersed in water and boiled for 20 minutes, after which the heating pad is able to return to its functions.

"Children's"

Children's heating pads are practically no different from classic salt heating pads. The principle of their work is the process of salt crystallization, which makes the product completely environmentally friendly. Most often, children's heating pads have an interesting shape and pattern for kids, they are often sold in the form of cartoon characters or fairy tales. When heated, the solution reaches a temperature comfortable for the child's body and cannot harm the child's body. However, you should consult your pediatrician before using these heating pads.

"Mega" for hands

This type of heating pads is represented by a set of rectangular plates, which are individually packed. Mega hand warmer easy way to warm the frozen fingers in a cold season. In order to activate the heating pad, remove from the plate protective film and paper, then fold the plate in half. Its principle of operation is constructed in such a way that the process of heat release occurs only when a fold is formed. It can easily be put in a jacket pocket or put inside a glove. The tool heats up for a long time, more than eight hours and its temperature is approximately 14 degrees.

Video: how to make a chemical heating pad with your own hands

As part of this video, the principle of making a chemical heating pad with your own hands is shown. Thanks to detailed explanations of manufacturing heating tool at each stage, the process of creating a device is greatly facilitated and becomes available to everyone without additional knowledge and skills.