Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapter 10 Transfer and Effects of Heat Energy, when matter is cooled …
Chapter 10
Transfer and Effects of Heat Energy
what does a change in temperature indicate?
temperature
⤷ is a measure of how hot an object is.
S.I. unit
for temperature:
kelvin (K)
common unit for temperature:
Celsius (°C)
heat energy
is
transferred
from the water in the
basin
to the water in the
beaker.
⤷ temperature of the water in the beaker
increased
heat energy
is
transferred
from the water in the
beaker
to the
ice cubes.
⤷ temperature of the water in the beaker
decreased
what effects does the transfer of heat energy have on an object?
when matter is
heated :arrow_right: expands
volume
increases
mass
remains the same
density
decreases
when heated,
:dash:
gases
expand the
most
🦾
solids
expand the
least
real life applications
mrt and railway tracks
expansion gaps
in the tracks provide
space
for the tracks to
expand
to prevent
rail buckling
(a phenomenon that occurs in tracks when the rails becomes deformed)
on hot days.
water pipes
metal pipes can
expand
or
contract
depending on the
temperature
and the
substance
they carry.
⤷
expansion bends
are made in these pipes to allow the pipes to
expand or contract without any damage.
tiled and concrete pavements
hot
weather → concrete
expands
cold
weather → concrete
contracts
continuous
expansion and contraction may
damage
the concrete.
⤷ expansion gaps are laid in between
concrete slabs
to provide
space for expansion
without any damage.
opening a jar
difficult to unscrew tight lid of a jar
⤷ placing the lid in
hot
water will cause the metal lid to
expand
, making it
less
tight and
easier to unscrew
.
bimetallic strip
⤷ helps regulate temperature in appliances
consists of
two different metals
that
expand
at
different rates
when heated.
example: brass (yellow in the diagram) can be fastened to iron (sliver in the diagram)
when
heated
, the metal that
expands more
will be on the
outside
of the curve.
when
cooled
, the metal that
contracts more
will be on the
inside
of the curve.
how does the transfer of heat energy occur?
conduction
⤷ is the transfer of heat energy without physical movement of the medium.
good conductors of heat
metals: aluminum, iron, steel and mercury
poor conductors of heat
non-metals: wood, paper, glass and plastic
liquids and gases
solids
are
generally better
conductors of heat compared to
liquids
and
gases
. this is because..
particles
in a
solid
arranged
more closely
together
unlike
liquids and gases
(spread further apart)
close arrangement enables transfer of heat to
occur faster
convection
⤷ is the transfer of heat energy by physical movement of the medium.
convections in fluids
when
heated
, gases/liquids
expand
, become
less dense
and
rise
.
cooler
and
denser
gas/liquid at the top
sinks
forming a
convection current
radiation
⤷ is the transfer of heat energy from a hotter body to a cooler body without the need for a medium
heat energy that is transferred by radiation may be
absorbed
or
reflected
greenhouse effect
⤷ is the warming of the surface of earth
greenhouse gases
on earth
traps
heat and
prevents
it from leaving earth's
atmosphere
by radiation
burning fossil fuels
increases
greenhouse gases
excess
greenhouse gases in the
atmosphere
increased
greenhouse effect
increases earth's temperature
(global warming)
when matter is
cooled :arrow_right: contracts
volume
decrease
mass
remains the same
density
increases
VS
