112425
Description
Mind Map by KMansfield699, updated more than 1 year ago
|
Created by KMansfield699
almost 11 years ago
|
|
Keeping Homes Warm
- Heat energy can be lost from houses in many
different places but there are ways of reducing
heat losses. Heat can be transferred from place to
place by conduction, convection and radiation.
- Dark matt surfaces are
better at absorbing heat
energy than light shiny
surfaces.
- Thermal energy can be transferred from
one place to another by conduction,
which involves particles. Metals are good
conductors of heat, but non-metals and
gases are usually poor conductors of
heat. Poor conductors are called
insulators. Heat energy is conducted
from the hot end of an object to the cold
end.
- The electrons in a metal can leave their
atoms and move about in the metal as
free electrons. The parts of the metal
atoms left behind are now charged
metal ions. The ions are packed closely
together and they vibrate continually.
The hotter the metal the more kinetic
energy the vibrations have. The kinetic
energy is transferred from hot parts of
the metal to colder parts by the free
electrons. These move through the
structure of the metal colliding with
ions.
- Convection occurs when particles with a lot of
heat energy in a liquid or a gas move and take
the place of particles with less heat energy. Heat
energy is travelled from hot places to cooler
places by convection.
- Liquids and gases expand when they are heated. This is
because the particles move faster when heated than they do
when they are cold. As a result, the particles take up more
volume. This is because the gap between them widens while the
particles stay the same size. The liquid/gas in hot areas is less
dense than the liquid/gas in cold areas, so it rises into the cold
areas. The denser cold liquid/gas falls into the warm areas.
Convection currents that transfer heat from place to place are
set up.
- Unlike conduction and convection, infrared radiation
is a type of electromagnetic radiation that involves
waves. Dull or rough surfaces are poor at reflecting
infrared radiation, but absorb it well. Shiny surfaces
are good at reflecting infrared radiation, but do not
absorb it well.
Want to create your own Mind Maps for free with GoConqr? Learn more.