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Why does water inside a thermos flask gets cooled after few days?
Wiki User
∙ 11y ago
This is due to insulation. Inside of the Thermos the liquid remains its placed temperature longer due to the insulating either stopping heat from reaching the fluid, or by stopping heat from leaving the fluid.
Wiki User
∙ 10y ago
Wiki User
∙ 11y agoBecause the thermos flask is not perfect. It allows heat (energy) to escape. Even though it reduces the heat loss rate, it still does not reduce it to zero.
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How do you heat a thermos?
I put hot water in the thermos and let sit for a few minutes until inside gets hot.
Must a flask be a good conductor of heat?
so as to keep the flask hot hereby keeping the hot water inside the flask hot.
Did you see the demonstration of water in a closed flask boiling when cooled?
Yes. I saw it, and I was able to reproduce it in my kitchen. I didn't have a flask, so I used a glass bottle with a screw-on cap. After the water in the bottle was boiled, then removed from the heat and the bottle plunged into ice, the bottle, of course, soon disintegrated, but not before the water inside it had clearly and distinctly resumed its boiling.
What happens with water vapor when its cooled?
when water vapour is cooled it condenses and falls as rain
What is a vacuum flask made of?
A vacuum flask is a type of flask that aims to stop all three forms of heat transfer. Conduction, convection and radiation. A vacuum flask prevents conduction by making a vacuum between the inside and the outside layer of the flask, so that the only solids that touch are the lid and the main body of the flask. This means the amount of conduction that occurs is minimised. One major drawback though, is when the hot water transfers heat with the cold air inside the flask, then the hot air transfers heat with the cold lid, and then on the likely chance that the lid is hotter than the surroundings, the lid transfers heat with the air molecules around it. This means that a considerable amount of heat is lost to the surroundings. The only way convection can occur is by the hot liquid or solid transferring heat with the trapped air inside the flask, although this only affects the temperature of the water by a bit, because most of the liquid condenses again. The flask is made so that radiation is reflected back of the sides, which is made of a shiny material. Also, the flask is not transparent; it is made of an opaque material, usually plastic or metal. The only way radiation can escape, is by the lid being taken off.
Why was it necessary to match the water levels inside and outside the cooled flask before removing it from the water bath?
So to equalize the pressure inside the flask with that of the atmosphere.
Is a thermos flask also good for keeping water cold for several hours?
Yes. The thermos flask can reduce the amount of heat travelling from the surroundings to the cold water
What do you call the object that keeps water hot for hours?
Thermos flask or vacuum flask.
What keeps water colder aluminum water bottles or stainless steel water bottles?
Vacuum insulated stainless steel bottles like one from Hydro Flask [see related link "hydro flask" below] or Thermos [see related link "thermos" below] will keep them coldest.
What happens if a cold substance kept in thermos flask?
It heats up and the water keeps warm for a certain amount of time
How do you heat a thermos?
I put hot water in the thermos and let sit for a few minutes until inside gets hot.
Why did the water rush into the erlenmeyer flask when it was submerged in the cold water?
1. When the flask was placed into the cold water, the colder air molecules in the flask move slower, putting out less pressure. With the decrease in air pressure inside the flask, the now greater pressure outside pushes water into the flask until the pressure inside equals the pressure outside.
Will a thermos keep cold or hot water at it's temperature range longer?
The rate of heat flow across a boundary such as the vacuum between the inside of the thermos flask and the ambient atmosphere is proportional to the temperature difference. So if you have hot water inside at say 90 C and an ambient of 30 C that is a difference of 60 C, whilst if you have cold water inside at 10 C the difference is 20 C. The heat flow will therefore be three times as much for the hot water as for the cold water, so the rate of change of temperature will be three times greater.
When the water level is higher inside than outside the flask is the gas pressure in the flask higher or lower or the same as the atmospheric pressure?
The gas pressure in the flask is lower than the atmospheric pressure when the water level is higher inside than outside the flask.
Must a flask be a good conductor of heat?
so as to keep the flask hot hereby keeping the hot water inside the flask hot.
What could you heat water in that would retain the heat the longest?
A vacuum would retain the heat best, hence a thermos flask has a vacuum around it =-)
Did you see the demonstration of water in a closed flask boiling when cooled?
Yes. I saw it, and I was able to reproduce it in my kitchen. I didn't have a flask, so I used a glass bottle with a screw-on cap. After the water in the bottle was boiled, then removed from the heat and the bottle plunged into ice, the bottle, of course, soon disintegrated, but not before the water inside it had clearly and distinctly resumed its boiling.
