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heat - Coggle Diagram
heat
difference in heat and temperature
the effect of the amount of heat
in a body on its temperature
an object containing a greater amount of heat
is hotter
has higher temperature
an object containing a lesser amount of heat
is colder
has lower temperature
object made up of the
at the same temperature
but with different amount of matter
do not contain the same amount of heat
same material
at the same temperature
the higher the amount of mater an object has
the higher amount of heat it contains
temperature is a measurement of the degree
on how hot or cold a body or place is
more heat is needed to warm up
a greater amount
same type of object
to the same temperature
heat is a form of energy
it can cause things to become
cold
hot
thermometers
the common units for measuring temperatures
degree celsius
degree fahrenheit
to read the temperature correctly,
our eyes must be at the same level as the liquid
which is positioned vertically
there are 2 common types of thermometers.
Laboratory thermometers
it contains a liquid
mercury or alcohol
in the glass tube
it measures a longer range of temperature
e.g. -10 to 110 degree celsius
it is used to measure the temperature
of things during experiment generally
clinical thermometers
it is used to measure the temperature
of the human body in
hospitals or clinics
it measures temperatures using
liquid
digitally
it measures a shorter range of temperature
e.g.35 to 42 degree celsius
when measuring the temperature of a liquid
the bulb of the thermometer must be placed
vertically in the liquid
a thermometer is used to
measure how hot or cold a body or place is
sources of heat
the main source of heat on earth is
the sun
heat from the sun helps to keep earth warm
fuels are things that produce heat when burn
e.g.
oil
petroleum
natural gas
wood
coal
sources of heat are
things that produce heat
some sources of light can be sources of heat
when light bulbs or lamps are switched on
they give off
heat
light
when fuels burn, they give of light
in the form of fire and heat
some electrical appliances can generate heat
e.g.
toaster
water heater
rice cooker
electric iron
oven
effect of heat gain heat lost
change in states of matter
when an object gains or losses heat
it can change in state
when an object gains heat
it can change its state from a solid to liquid
or from liquid to gas
this process is called boiling
this process is called melting
when can object loses heat
it can change its state from a gas to liquid
or liquid to soild
this process is called freezing
this process is called condensation
during the process of changing its state
the matter continues to gain heat or lose heat
without changes in the temperature
hence its temperature will remain the same
e.g
when ice is melting
its temperature remains 0 degree celsius
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when water is boiling
its temperature remains 100 degree celsius
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expansion and contraction of matter
heat flow can cause matter to expand or contract
when matter gains heat ,its expands
or becomes bigger
e.g.
before heating the metal ball cannot pass through the metal ring
after the metal ring is heated, the metal ball can pass through
this because the metal ring expands or becomes bigger
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when matter loses heat, it contracts
or becomes smaller
e.g.
before cooling, the metal ball cannot pass through the metal ring
after the metal ball is cooled, the metal ball can pass through
this is because the metal ball contracts or become smaller
so there is space for the metal ball to pass through
change in temperature
heat gain or heat loss can cause
a change in temperature of things
when an object gain heat
its temperature increases
when an object loses heat
its temperature decreases
a graph can be used to show changes in the temperature
of an object caused by heat gain or heat loss
good or poor conductors of heat
the thickness of the material
can affect how fast heat flow
take place in the materials
info
when the thickness of the material increase
heat flowing through it becomes slower
so more time is needed to transfer
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both good and poor conductors of heat
have useful applications in our daily lives
good conductors of heat
metals are used to make cooking utensils
or heating element in some electrical appliances
such as oven toasters as they allow heat to flow
through them quickly to cook or heat up food
poor conductors of heat
materals such as wool fur and feathers
are used to make winter clothing or shoes
as they are poor conductors of heat
hence people can keep their body warm in cold enviroment
however not all object allow heat to pass through them the same weight
good conductors of heat are objects
that allow heat flow through them easily
e.g
metals
zinc
aluminium
silver
gold
copper
steel
iron
poor conductors of heat are objects
that do not allow heat to flow through them easily
e.g
plastics
rubber
glass
air
fabrics
wood
the conduction of heat by different materials
can be used to explain some situation in our daily lives
a metal spoon feels colder than a plastic spoon
at the same temperature
metals are good conductors of heat than plastic
when we touch the metal spoon and the plastic spoon
metal conducts heat away from our hand more quickly than the plastic spoon
hence our hand loses heat faster when we touch the metal spoon
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our feet feel colder when walking
on the marble floor than on a wooden floor
at the same temperature
marbles conduct heat away from our feet
faster than wood
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when two object touch each other
heat flow take place when both object
have different temperatures
heat always flows from a hotter object to a a colder object
heat flow
through heat flows, an object can become
hot
gaining heat
cold
losing heat
in our surroundings heat flow will continue
to take place between
hot
until they all reach the
room temperature
it is the same temperature between the objects
and the surrundings
e.g
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cold
an object or a place can become
cold
because of heat flow
hot
heat always flows
from a hotter object to a colder object or place
until all of them reaches the same temperature
introduction to heat
heat is a form of energy
it can make things hot
heat is not matter
but we can feel its effect by
our sense of touch