[Search Doc Brown's science website]

SITEMAP   School Physics Notes: Thermal energy 1.5 Minimising thermal energy transfer

UK GCSE level age ~14-16 ~US grades 9-10 Scroll down, take time to study content or follow links

Thermal energy transfer: 1.5 Applications of thermal energy transfer science - thermal conductivity and insulation - design of a vacuum flask (thermos flask)

Doc Brown's Physics exam study revision notes

INDEX for physics notes on thermal energy transfer by conduction, convection and radiation

1.5 More on the applications of thermal energy transfer science

See also More on methods of reducing heat transfer eg in a house and investigating insulating properties of materials

Thermal conductivity of good insulators OR good conductors

The thermal conductivity of a material is a measure of efficiently heat is transferred through a material by conduction.

Materials like metals are very good heat conductors and transfer thermal energy very quickly.

Materials like stone, brick, wood and concrete etc. are poor heat conductors and have low thermal conductivities.

Thermal conductivity data is important when considering the material required to fulfil a particular application e.g. in heating systems when in one situation you might want good insulation (e.g. in loft) and in another rapid heat transfer (copper piping inside a hot water tank).


The design of a vacuum flask and other examples of a 'thermos flask'

design features of thermos vacuum flask explained minimising heat transfer by conduction convection radiation gcse physics igcse

The 'thermos' vacuum flask is a container designed to keep hot liquids hot and cold liquids cold. Diagram on the right.

It is designed to minimise thermal energy (heat) transfer by conduction, convection or radiation, both in an out of the container.

The flask is double walled with a vacuum (of nothing!) between the walls.

The vacuum ensures there is no thermal energy transfer by conduction - no material to vibrate.

If the double-walled flask is made of glass, the inner surfaces exposed to the vacuum are silvered to reflect back any thermal radiation (infrared).

If the flask is steel, the surfaces are shiny and reflect infrared in the same way.

The top cap should be a poor conductor of heat energy (thermal insulator), and is often made of plastic or incorporates a plastic seal.

Both double walls and the cap help minimise losses by convection. The design ensures no air can pass over any surface that is in contact with the fluid.

Insulated cups, flasks and jugs come in all sizes - illustrated by the pictures below.

Left picture:

A double walled plastic jug and several steel vacuum flasks

Right picture:

As above plus on the left a plastic insulated coffee cup, sometimes with an added cardboard hand holder for extra insulation.

Your knowledge of examples of heat transfer situations should include the ...

The design of a vacuum flask

How to reduce the energy transfer from a building

How humans and other animals cope with low temperatures by ways of increasing thermal insulation - adaptations.

See Homeostasis - thermoregulation, control of temperature


Notes on thermal energy transfer by conduction, convection, radiation

Keywords, phrases and learning objectives for minimising thermal energy transfer - insulation

Be able to describe and explain ways of minimising the transfer of thermal energy e.g. the design of vacuum flask (thermos flask)

Be able to explain applications of thermal energy transfer science including thermal conductivity and insulation materials.


TOP of page

INDEX for physics notes on thermal energy transfer

INDEX of all my THERMAL ENERGY notes


email doc brown - comments - query?

BIG website, using the [SEARCH BOX] below, maybe quicker than navigating the many sub-indexes

HOME PAGE of Doc Brown's Science

Basic Science Quizzes for UK KS3 science students aged ~12-14, ~US grades 6-8

BiologyChemistryPhysics for UK GCSE level students aged ~14-16, ~US grades 9-10

Advanced Level Chemistry for pre-university age ~16-18 ~US grades 11-12, K12 Honors

Find your GCSE/IGCSE science course for more help links to all science revision notes

Use your mobile phone in 'landscape' mode?

SITEMAP Website content Dr Phil Brown 2000+. All copyrights reserved on Doc Brown's physics revision notes, images, quizzes, worksheets etc. Copying of website material is NOT permitted. Exam revision summaries and references to GCSE science course specifications are unofficial.

Using SEARCH some initial results may be ad links you can ignore - look for docbrown

Notes on thermal energy transfer by conduction, convection, radiation