What needs to be done to cool the coffee faster. Coffee with cream - cedar
Coffee with cream April 23rd, 2012
What do you think will cool down faster: (1) a cup of hot coffee, to which a portion of cream was immediately added, or (2) a cup of coffee, which cools down without cream, and exactly the same amount of cream was added later? Numerical example: coffee 250 g, cream is added 60 g, cream temperature 6 degrees. The initial temperature of the coffee is 83 degrees, the temperature in the room is 22 degrees. We are waiting for 15 minutes, in which cup is the temperature lower?
Simple model (Newton-Richmann law): the cooling rate is proportional to the temperature difference, that is, T "(t) = c(T-Tv), where Tv is the air temperature, and all physical properties (interface area, heat capacity of a liquid, etc.) are packed into a constant c... Moreover, this magic constant also does not depend on the proportion of coffee / cream. Solution: coffee cools down exponentially, then it is necessary to take into account the proportional contribution of the cream. In this model, the addition of cold cream slows down the cooling rate and (2) cools down faster
... In other words, the contribution of cream (to the sudden drop in temperature) is different when the coffee is hot and when it has already cooled down (see the graphs in the comments).
Formula for a numerical example: the temperature of the coffee without cream drops as T (t) = 22 + 61exp (-ct). (see in the comments bitoff ).
In the literature, a coffee cooling table has been found, from which it is possible to determine the constant c(see comments). However, the data does not fit the exponential very well, which leads to the question of the accuracy of measurements, as well as the accuracy of the model. The temperature measurement error in the table is 0.1 degrees, and the estimate of the temperature difference between the liquid in the cups according to the conditions of the numerical example gives 1-2 degrees.
UPDATE (27 / 4-29 / 4). About the scope of the model: Experimental measurements can show even more difference than the model predicts!
Experiment data on cooling coffee (table from the book Gould, Tobochnik "Computer simulation in physics", M. Mir, 1990, p. 35):
1. Comparison of the measurement results from the table with the exponential model: Conclusion: the experimental data from the book do not fall so badly on the exponent, with the exception of the first two or three points. From the fourth point, the deviation is less than one degree.
Practical advice:
1. If you want to cool the coffee as quickly as possible: Pour into a thin-walled metal cup, place in cold water and stir. Then add the cream.
2. If, on the contrary, you want to keep the coffee hot as long as possible: preheat the thermos (especially with a metal flask), pour coffee into it just under the cork, close it immediately.
Trufanova Olga Nikolaevna,
Physics teacher
municipal budgetary educational institution
municipal formation "City of Arkhangelsk"
"Secondary school number 14"
PHYSICS IN THE KITCHEN.
Lesson summarizing by topic:
"Thermal phenomena", "Changes in the aggregate states of matter"
8th grade.
The purpose of the lesson is to create conditions for the generalization and systematization of students' knowledge on the topics of the course of physics of the 8th grade "Thermal phenomena", "Changes in the aggregate states of matter."
Educational objectives of the lesson
the formation of the ability to find the manifestation of thermal phenomena: thermal conductivity, convection, radiation, phase transitions in practical life;
the formation of skills and abilities to apply the knowledge gained to explain the thermal phenomena encountered in everyday life, to explain the principle of operation of technical devices, household items;
solving practical problems of everyday life.
Developing lesson tasksare represented by a set of student and teacher actions aimed at:
development of the ability to summarize the learned facts
development of cognitive interest through the organization of game, competitive situations.
Educational tasks of the lessonare represented by a set of actions of the student and teacher, aimed at
demonstration of the practical significance of thermal phenomena and processes in everyday life;
the formation of conviction in the possibility of cognition of natural phenomena;
the formation of skills to work in a group, to present their arguments and explanations, to lead a discussion.
During the classes:
Organizational stage. (2 minutes).
The kitchen is the most comfortable and functional room in the house: food is stored there, food is prepared, we have breakfast and lunch there, there are conversations and secrets ...
At the same time kitchen appliances and utensils are constantly being modernized, although the kitchen is the most ancient part of the dwelling. How can this be explained? I propose to consider this question from the perspective of a physicist and give an answer to it at the end of the lesson.
There are kitchen utensils on the teacher's table. On the slide:
What physical processes and phenomena can be
find in the kitchen?
Let's start to reason.
2. The main part. (37 minutes).
Stage 1 of the conversation (up to 8 minutes). On the slide, the question:" Who cares?"
Do we always think about how to use household items more correctly or more effectively?
Which teapot cools down faster, aluminum matt or chrome polished?
Thermoses are made with a foam covered flask and a vacuum interlayer. Which type of thermos is more efficient?
Why are wooden spoons used when making jam, and not metal ones?
Hot coffee was poured into a cup. What should be done to make the coffee cool faster: pour cold milk into it immediately or after a while?
In which cup, dark or white, will the water cool faster?
You need to cool the water. What will you do - put the pot on ice, or put the ice on the lid that is adjacent to the water? Why?
Glasses often crack when hot water is poured into them. Which glass is more likely to crack, faceted or smooth?
Why put a spoon in a glass when hot tea is poured?
Why fight limescale in your kettle? What's the difference: is there scale or not?
Let's summarize.
Stage 2 of the conversation (10 minutes). On the slide, the question:"How it works?"
Do every family use these devices? How do they work? What are they for?
Pupils of the class prepared in advance mini-messages on each of the devices, devices. The speaker is asked to prove the necessity of using them.
Pictures on the slides: 1. KITCHEN HOOD.
2. COUPLER.
3.KITCHEN "TRUNKIES": Hot stand, oven mitt (mitten), "hot water bottle" for the kettle (saucepan). What unites them?
Let's summarize.
Stage 3 conversation (up to 9 minutes). On the slide:"About products and their preparation"
Can physical knowledge be applied to food preparation?
For quick soup preparation, which pot do you choose?
(Analyze each selected option by teams)
What makes the pot lid jump when boiling water?
Why is it not necessary to stir the soup during cooking, but the semolina must be constantly stirred?
Why does it take longer to cook potatoes in water than in a double boiler with steam at the same temperature?
Once boiled water boils less violently than raw water. Why?
Why doesn't an egg taken out of boiling water burn your hands?
Why does milk turn sour?
Why does the duration of cooking meat until cooked do not depend on whether the broth is boiling over high or low heat?
Why does butter sometimes foam when someone wants to melt it in a hot skillet?
To make croutons, cut the bread into thin slices or small cubes, place it on a slightly heated frying pan or baking sheet and place in the oven. Why is it done this way?
Let's summarize.
Stage 4 conversation (10 minutes). On the slide:"Let's make a menu"
Creative task.
Working, you waste your inner energy. How do you replenish it?
The guys are united in groups of 4 people. The group is given 5 minutes to work on the assignment. They draw up the menu and the daily routine on sheets of A1 format. Then the menu is "protected" by each group. (The sheets are attached to the magnetic board).
Using two tables: energy expenditures and calories in food, create a student's menu for 1 day. Choose the conditions of the day mode yourself. At the end of the work, answer the question: "Will food replenish energy costs for the day?"
(Students are offered a table of energy consumption. Approximate content: (for 1 hour per 1 kg of a person's weight) when preparing lessons - 9000 J; when charging - 16000 J; when lying down - 4000 J; when swimming - 30000 J; during sleep - 4000 J; when walking - 15000 J.
A table of food calories is offered. For convenience, the unit of measurement of energy kcal should be converted in advance to J / g. For example: bread - 9000J / g; sugar - 17150 J / g; milk - 3000 J / g; meat - 7500 J / g; potatoes - 4000 J / g; oil - 33000 J / g; vegetables and fruits - 600 - 2000 J / g; eggs - 7000 J / g).
Let's summarize.
3. Generalization, summing up the results of the work, homework (6 minutes).
Key question:“What did you take note of from the lesson? What is the person doing in the kitchen? Why are kitchen appliances and utensils constantly being modernized, although the kitchen is the most ancient part of the home? "
Homework:Conduct an independent theoretical or practical research on the topic: "Does water boil in tubular pasta during cooking?"
Enough level
1. Which of the following substances have good thermal conductivity:
copper, air, aluminum, water, glass, water vapor?
Answer: have good thermal conductivity: copper and aluminum
2. Which of the following substances have poor thermal conductivity:
cardboard, iron, rubber, steel, paper?
Answer: have poor thermal conductivity: cardboard, rubber, paper
3. Hot water is poured into aluminum and glass pans of the same capacity.
Which of the pots will heat up faster to the temperature of the water poured into it?
Answer: The aluminum pan will heat up faster because
that she has more thermal conductivity
4. Will regular or porous bricks provide better thermal insulation for the building?
porous brick will provide better thermal insulation of the building because
that voids filled with air have poor thermal conductivity (?)
5. In which footwear the feet freeze more in winter: spacious or tight?
Answer: in a cramped one, since there is no air gap in it,
with low thermal conductivity
6. Which type of heat transfer plays a major role in heating the water in the kettle,
standing on the stove?
Answer: the main role in heating the water in the kettle convection plays
7. It is necessary to quickly cool the water poured into the tank.
Is it better to put the tank on ice or put ice on the tank lid?
Answer:in order to quickly cool the water poured into the tank,
it is necessary to put ice on the tank lid
during convection, warm layers of water rise up
when in contact with a cold lid cool down (?)
8. Which dress is less hot in summer: light or dark?
Answer: in a light dress in summer it is less hot because
that it absorbs less solar energy,
transmitted by radiation
9. Which soil under the same conditions warms up more strongly in the sun -
podzolic or black earth?
Answer: the sun warms up the chernozem soils more because
that they absorb more energy from the sun's rays
10. Tea is kept hot in a thermos. Is it possible to keep cold fruit drink in it?
Average level
1. Why are the faucet handles of hot water tanks made of wood?
Answer: the handles of the taps at the hot water tanks are made of wood because
2. In summer, ice is kept under a layer of sawdust and earth. Why?
Answer: in summer, ice is kept under a layer of sawdust and earth because
that they have poor thermal conductivity
3. In which case a piece of ice introduced into the room will melt faster:
when they just put it on the table or when they cover it with a woolen scarf?
Answer: A piece of ice brought into the room will melt faster when it is simply placed on the table (?)
4. Why are fuel storage tanks painted with “silver” paint?
Answer: at oil depots, fuel storage tanks are painted with "silver" paint because
that light surfaces do not heat up well under the influence of radiation (?)
5. Why are heating batteries in the room located near the floor, and not near the ceiling?
Answer: cold air entering through a window is heavier than warm air,
and so it sinks down where it heats up from the central heating battery
6. Which of the bodies - solids, liquids or gases - have the lowest thermal conductivity? Why?
Answer: gases have the lowest thermal conductivity because
that gas molecules are at a great distance from each other
and do not interact well (?)
7. Where is it necessary to keep a thermometer to determine the air temperature -
in the shade or in the sun?
Answer:to determine the air temperature, the thermometer must be kept in the shade because
what… (?)
8. What will cool down faster: a glass of compote or a glass of jelly? Why?
Answer: a glass of compote will cool down faster because
that in it the mutual attraction between the molecules is less
and convection is faster (?)
9. Why are plants in lowlands more likely to die from frosts than in highlands?
Answer: cold air is heavier than warm air and therefore it sinks down
it is colder in the lowlands on a cloudless night than in the highlands (?)
10. Why does the snow melt faster in the city in spring than in the field?
Answer:in spring the snow melts faster in the city because buildings under the influence of solar radiation warm up well and transfer part of their energy to the snow (?)
High level
1. Which bodies - solid, liquid or gaseous - have the best thermal conductivity?
Answer: solids have better thermal conductivity because,
that their molecules are at a small distance from each other
and interact well (?)
2. In what bodies - liquids, solids, gases - convection is observed? Why?
Answer: convection is observed in liquids and gases because
that in them the mutual attraction between the molecules is less and the molecules can move freely (?)
3. At what temperature will both metal and wood feel the same heat to the touch?
Answer: both metal and wood will feel equally hot at a temperature of 36.6 0 C because at this temperature there will be no (?)
4. Cool down the lemonade bottle as quickly as possible. Where should the bottle be placed for this: in snow or in crushed ice, if their temperature is the same?
Answer: in order to quickly cool a bottle of lemonade, it must be placed in crushed ice, which has a higher thermal conductivity, so heat transfer will go faster (?)
5. When is it more convenient for sailing ships to enter the harbor - during the day or at night?
Answer: it is more convenient for sailing ships to enter the harbor during the day, when the land is warmed up by the sun faster, the heated air rises, and it is replaced by a cold air stream from the side of the sea - a daytime breeze (?)
6. Hot coffee is poured into a cup. What should be done to make the coffee cool faster: pour milk into it immediately or after a while?
Answer:to cool hot coffee faster milk must be poured into it after a while
a film forms on the surface of the coffee, which has poor thermal conductivity (?)
7. Which factory pipes are better: iron or brick?
Answer: brick factory pipes are better because
that they have poor thermal conductivity
at the top of the pipes are surrounded by a layer of cold air,
so the draft in the brick pipe is better (?)
8. When is the draft in the pipes better - in winter or summer? Why?
Answer: draft in pipes is better in winter because
what …(?)
9. Why do window panes begin to freeze from below and to a greater extent than from above?
Answer: cold air is heavier than warm air and therefore it sinks down (?)
10. Will a candle burn on board the space orbital complex?
Answer: no, because convection is carried out due to the force of Archimedes,
which does not occur in a state of weightlessness
11. Why do we feel warmer in a room at 20 ° C,
than in water at a temperature of 25 ° C?
Answer: the thermal conductivity of water is greater, therefore, heat exchange in it is faster,
body temperature drops rapidly (?)
12. Why do many animals sleep curled up in a ball in cold weather?
Answer: the smaller the surface of the animal's body, the less heat it is
gives off to the air around it (?)
13. Why is the highest air temperature not at noon but in the afternoon?
Answer: during the day, the surface of the land is very hot under the influence of solar radiation.
and in the afternoon heats the air by convection (?)
14. On a hot day, the dry bulb reads 35 ° C.
Will the thermometer readings change if a fan is turned on next to it?
Consider two cases: a) the thermometer is in the shade; b) the thermometer is illuminated by the sun.
Answer: if on a hot day the dry thermometer is in the shade and the air flow from the fan is directed at it, then its temperature will not change
if on a hot day the dry thermometer is illuminated by the sun and the air flow from the fan is directed at it, then its temperature will decrease, because in this case convection occurs faster (?)
15. How do you arrange a greenhouse? Why is the air temperature higher inside greenhouses than outside?
Answer: greenhouses are used to protect plants from frost.
Glass frames are good for solar radiation. During the day, the soil heats up.
At night, the greenhouse prevents warm air from moving upward. Therefore, the temperature in the greenhouse is higher than in the surrounding area.
Additionally:
1. For what purpose in winter, in severe frost, the face is sometimes smeared with a fat cream?
2. The longer the enamel teapot is in use, the slower the water boils in it. Why?
3. Why in the countries of Central Asia do locals wear hats and wadded robes during extreme heat?
4. Why is the frost stronger on clear winter nights than in cloudy weather?
4. If a clear night is expected in spring or autumn, gardeners make fires that give a lot of smoke,
the enveloping plant. What for?
5. There is a known case when a parachutist with an open parachute, instead of going down, climbed up. How could this happen?
6. With the help of a thermal imager ("night vision" device), various bodies can be detected,
even slightly heated, and regardless of whether these bodies are illuminated or are in complete darkness. What physical phenomenon is used in these devices?
7. In which case the heated part will cool faster: if you put it on a wooden support
or on a steel plate?
8. Which parts of the earth's surface are heated more strongly in sunny weather:
plowed field or green meadow, dry or moist soil? Why?
9. Why does it blow cold even from well-sealed windows in winter?
10. In which teapot - white or dark - will water boil faster?
11. Why is there more thrust in tall tube furnaces than in low tube furnaces?
12. Why does a stone floor seem colder than a wooden floor in the same room?
13. Why do experienced housewives prefer to fry in cast-iron pans,
and not on aluminum?
14. Which type of heat transfer is accompanied by the transfer of matter?
15. Why is the highest temperature not at noon but in the afternoon?
16. The Earth continuously radiates energy into outer space. Why doesn't the Earth freeze?
17. When is energy transmitted by radiation? Explain with an example.
18. Why do aspen leaves sway in calm weather?
19. Why does a thin plastic film protect the plant from the night cold?
20. Why, while the stove starts to heat up in the room,
is there a drop in temperature?
TYPES OF HEAT TRANSFER.
Enough level
1. Which of the following substances have good thermal conductivity:
copper, air, aluminum, water, glass, water vapor?
Answer: have good thermal conductivity: copper and aluminum
2. Which of the following substances have poor thermal conductivity:
cardboard, iron, rubber, steel, paper?
Answer: have poor thermal conductivity: cardboard, rubber, paper
3. Hot water is poured into aluminum and glass pans of the same capacity.
Which of the pots will heat up faster to the temperature of the water poured into it?
Answer: The aluminum pan will heat up faster because
that she has more thermal conductivity
4. Will regular or porous bricks provide better thermal insulation for the building?
porous brick will provide better thermal insulation of the building because
that voids filled with air have poor thermal conductivity (?)
5. In which footwear the feet freeze more in winter: spacious or tight?
Answer: in a cramped one, since there is no air gap in it,
with low thermal conductivity
6. Which type of heat transfer plays a major role in heating the water in the kettle,
standing on the stove?
Answer: the main role in heating the water in the kettle convection plays
7. It is necessary to quickly cool the water poured into the tank.
Is it better to put the tank on ice or put ice on the tank lid?
Answer:in order to quickly cool the water poured into the tank,
it is necessary to put ice on the tank lid
during convection, warm layers of water rise up
in contact with the cold lid cool down (?)
8. Which dress is less hot in summer: light or dark?
Answer: in a light dress in summer it is less hot because
that it absorbs less solar energy,
transmitted by radiation
9. Which soil under the same conditions warms up more strongly in the sun -
podzolic or black earth?
Answer: the sun warms up the chernozem soils more because
that they absorb more energy from the sun's rays
10. Tea is kept hot in a thermos. Is it possible to keep cold fruit drink in it?
Average level
1. Why are the faucet handles of hot water tanks made of wood?
Answer: the handles of the taps at the hot water tanks are made of wood because,
that they have poor thermal conductivity
2. In summer, ice is kept under a layer of sawdust and earth. Why?
Answer: in summer, ice is kept under a layer of sawdust and earth because
that they have poor thermal conductivity
3. In which case a piece of ice brought into the room will melt faster:
when they just put it on the table or when they cover it with a woolen scarf?
Answer:a piece of ice brought into the room will melt faster when it is simply placed on the table (?)
4. Why are fuel storage tanks painted with “silver” paint?
Answer:at oil depots, fuel storage tanks are painted with "silver" paint because
that light surfaces do not heat up well under the influence of radiation (?)
5. Why are heating batteries in the room located near the floor, and not near the ceiling?
Answer: cold air entering through a window is heavier than warm air,
and so it sinks down where it heats up from the central heating battery
6. Which of the bodies - solids, liquids or gases - have the lowest thermal conductivity? Why?
Answer:gases have the lowest thermal conductivity because
that gas molecules are at a great distance from each other
and do not interact well (?)
7. Where is it necessary to keep a thermometer to determine the air temperature -
in the shade or in the sun?
Answer:to determine the air temperature, the thermometer must be kept in the shade because
what… (?)
8. What will cool down faster: a glass of compote or a glass of jelly? Why?
Answer:a glass of compote will cool down faster because
that in it the mutual attraction between the molecules is less
and convection is faster (?)
9. Why are plants in lowlands more likely to die from frosts than in highlands?
Answer:cold air is heavier than warm air and therefore it sinks down
it is colder in the lowlands on a cloudless night than in the highlands (?)
10. Why does the snow melt faster in the city in spring than in the field?
Answer:in spring the snow melts faster in the city because buildings under the influence of solar radiation warm up well and transfer part of their energy to the snow (?)
High level
1. Which bodies - solid, liquid or gaseous - have the best thermal conductivity?
Answer:solids have better thermal conductivity because
that their molecules are at a small distance from each other
and interact well (?)
2. In what bodies - liquids, solids, gases - convection is observed? Why?
Answer:convection is observed in liquids and gases because
that in them the mutual attraction between the molecules is less and the molecules can move freely (?)
3. At what temperature will both metal and wood feel equally hot to the touch?
Answer: both metal and wood will feel equally hot at a temperature of 36.6 0 C because at this temperature there will be no heat transfer (?)
4. It is necessary to cool down the lemonade bottle as soon as possible. Where should the bottle be placed for this: in snow or in crushed ice, if their temperature is the same?
Answer: in order to quickly cool a bottle of lemonade, it must be placed in crushed ice, which has a higher thermal conductivity, so heat transfer will go faster (?)
5. When is it more convenient for sailing ships to enter the harbor - during the day or at night?
Answer: It is more convenient for sailing ships to enter the harbor during the day, when the land is warmed up by the sun faster, the heated air rises, and it is replaced by a flow of cold air from the side of the sea - a daytime breeze (?)
6. Hot coffee is poured into a cup. What should be done to make the coffee cool faster: pour milk into it immediately or after a while?
Answer:to cool hot coffee faster
milk must be poured into it after a while
a film forms on the surface of the coffee, which has poor thermal conductivity (?)
7. Which factory pipes are better: iron or brick?
Answer:brick factory pipes are better because
that they have poor thermal conductivity
at the top of the pipes are surrounded by a layer of cold air,
so the draft in the brick pipe is better (?)
8. When is the draft in the pipes better - in winter or summer? Why?
Answer:
draft in pipes is better in winter because
what …(?)
9. Why do window panes begin to freeze from below and to a greater extent than from above?
Answer:cold air is heavier than warm air and therefore it sinks down (?)
10. Will a candle burn on board the space orbital complex?
Answer: no, because convection is carried out due to the force of Archimedes,
which does not occur in a state of weightlessness
11. Why do we feel warmer in a room at 20 ° C,
than in water at a temperature of 25 ° C?
Answer:the thermal conductivity of water is greater, therefore heat exchange in it is faster,
body temperature drops rapidly (?)
12. Why do many animals sleep curled up in a ball in cold weather?
Answer:the smaller the surface of the animal's body, the less heat it is
gives off to the air around it (?)
13. Why is the highest air temperature not at noon but in the afternoon?
Answer:during the day, the surface of the land is very hot under the influence of solar radiation
and in the afternoon heats the air by convection (?)
14. On a hot day, the dry bulb reads 35 ° C.
Will the thermometer readings change if a fan is turned on next to it?
Consider two cases: a) the thermometer is in the shade; b) the thermometer is illuminated by the sun.
Answer: if on a hot day the dry thermometer is in the shade and the air flow from the fan is directed at it, then its temperature will not change
if on a hot day the dry thermometer is illuminated by the sun and the air flow from the fan is directed at it, then its temperature will decrease, because in this case convection occurs faster (?)
15. How do you arrange a greenhouse? Why is the air temperature higher inside greenhouses than outside?
Answer: greenhouses are used to protect plants from frost.
Glass frames are good for solar radiation. During the day, the soil heats up.
At night, the greenhouse prevents warm air from moving upward. Therefore, the temperature in the greenhouse is higher than in the surrounding area.
Additionally:
1. For what purpose in winter, in severe frost, the face is sometimes smeared with a fat cream?
2. The longer the enamel teapot is in use, the slower the water boils in it. Why?
3. Why in the countries of Central Asia do locals wear hats and wadded robes during extreme heat?
4. Why is the frost stronger on clear winter nights than in cloudy weather?
4. If a clear night is expected in spring or autumn, gardeners make fires that give a lot of smoke,
the enveloping plant. What for?
5. There is a known case when a parachutist with an open parachute, instead of going down, climbed up. How could this happen?
6. With the help of a thermal imager ("night vision" device), various bodies can be detected,
even slightly heated, and regardless of whether these bodies are illuminated or are in complete darkness. What physical phenomenon is used in these devices?
7. In which case the heated part will cool faster: if you put it on a wooden support
or on a steel plate?
8. Which parts of the earth's surface are heated more strongly in sunny weather:
plowed field or green meadow, dry or moist soil? Why?
9. Why does it blow cold even from well-sealed windows in winter?
10. In which teapot - white or dark - will water boil faster?
11. Why is there more thrust in tall tube furnaces than in low tube furnaces?
12. Why does a stone floor seem colder than a wooden floor in the same room?
13. Why do experienced housewives prefer to fry in cast-iron pans,
and not on aluminum?
14. Which type of heat transfer is accompanied by the transfer of matter?
15. Why is the highest temperature not at noon but in the afternoon?
16. The Earth continuously radiates energy into outer space. Why doesn't the Earth freeze?
17. When is energy transmitted by radiation? Explain with an example.
18. Why do aspen leaves sway in calm weather?
19. Why does a thin plastic film protect the plant from the night cold?
20. Why, while the stove starts to heat up in the room,
is there a drop in temperature? what ... and the purpose, because what temperature air at floor level ...
A. M. Shepelev how to build a rural house
Document... - thermal insulation; ... porous brick ... bricks, better iron ore. Badly burnt brick ... emptiness(air bags) reducing its weight and thermal conductivity... For monolithic one-story walls buildings ... to provide the best ... because what sucked into these cracks air ...
Question The composition of the installation process. Method classification
Document... , what glass is heat conductive material ... of the layer, filled dehydrated by air... Double-glazed windows possess high ... buildings and structures. Railroad tracks must be connected to them and provided supply of electricity, compressed air ...
The life of a modern person is unthinkable without sophisticated technology. Even in his home, he is surrounded by many devices and gadgets, most of which require a
Document... possesses good electrical conductivity, thermal conductivity, 3.5 times lighter than copper. On the air... power supplies. That's why what really effective protection ... buildings over 80% of their time. Modern homes often have good sound and thermal insulation ...
Read also ...
- Chicken liver pate
- Delicious zucchini with cheese in sour cream in the oven - a step by step recipe with video Zucchini recipes in the oven with sour cream
- Banana rice and corn flour pancakes (gluten free) with homemade banana sauce Banana pancakes with semolina
- Cabbage casserole with chicken Chicken fillet casserole with cabbage
