How is heat transferred through the glass wall of a boiling tube?

Answer 1

In liquids and solids, the heat conduction occurs through the valance electrons of the material. When you have a gas, most of the heat is conducted through radiation. When you conduct heat through a vacuum, it's all by radiation.

Answer 2

Thermal energy is is very general - heat simply passes through like any other solid with the molecules vibrating next to each other creating friction and effectivly passing the heat though them.

However if your on about a greenhouse then this is different, short wave radiation from the sun has enough energy to penetrate the glass and reach the earth but long wave radiation emitted from the earth does not have enough energy to penetrate the glass to remains inside heating the inside of the greenhouse.

Answer 3

There are two mechanisms by which a vacuum flask retains the temperature of the contents. [Both hot or cold.]

Construction The vacuum flask is made as a double-walled flask, with the two walls joined only towards the neck, the space between the walls evacuated, and the vacuum-facing surfaces silver-coated.

1 By having a vacuum between the walls of the flask, this reduces heat transfer by conduction or convection.

2 By having the walls of the flask (where they face the vacuum) silver coated, this reduces the heat transfer by radiation.

Vacuum flasks are made of glass or stainless steel. The steel versions are much more robust, but at the expense of being a poorer heat retainer. This is because the heat may still be transferred between the two flasks at the neck where they are joined. The mirrors facing the vacuum may be inferior to the sliver coated glass.

Answer 4

It isn't reduced because of conduction, conduction is a way to transfer heat

btw a vaccum flask works like this:

1. it has a shiny surface facing the liquid which reflects the heat back into the liquid.
2. if you look at a picture (below is a link) then u'll see that there is vaccum between the inner and the outer container. heat cannot travel in vaccum.
3. also to prevent heat from escaping upwards, we generally use rubber corks (rubber is a insulator)

Answer 5

In order for heat to transfer by convection, there has to be air or water in order for the molecules to move from place to place. So both these heat transfer techniques require a medium of some sort. In a vacuum, there's no particles at all, so there is no medium present in order for these heat transfers to apply.

Answer 6

Will glass transfer thermal energy? Would wood or metal be a better conductor? Why?

Answer 7

Quantum Tunneling transfers vibrational energies from one molecule to the next. Second law of thermodynamics dictates this will occur until both have the same amount of vibrational energy.

Answer 8

Conduction can only occur in solids so there is a vacuum between the inner layer of the flask and the outer surface of the flask which almost eliminates heat losses through conduction.

Answer 9

by conduction and radiation ;)

Answer 10

this fails