Zusammenfassung der Ressource
P1.1 - Energy Transfer
By Heating
- INFRARED RADIATION
- All objects EMIT and ABSORB infrared
radiation. The hotter the object, the more
infrared radiation it emits.
- Dark/Matte surfaces are good absorbers of infrared
radiation however they are bad REFLECTORS of
radiation. Light and shiny surfaces are good reflectors
of infrared radiation but BAD absorbers.
- KINETIC THEORY
- Kinetic theory is used to explain the different states of
matter. The particles of solids, liquids and gases have
different amounts of energy.
- .In a GAS,the particles are usually
far apart and move at random
much faster. NO FIXED SHAPE
AND CAN FLOW.
- In a SOLID, the particles vibrate
around fixed positions so the solid
has a FIXED shape.
- In a LIQUID, the particles are in
contact with each other but can move
about at random. They don’t have a
fixed shape and can fit the shape of
their container.
- CONDUCTION
- Conduction occurs mainly in solids. Most liquids
and gases are poor conductors
- Metals are EXCELLENT conductors. Metals
have FREE ELECTRONS. Poor conductors are
called insulators.
- CONVECTION
- Convection occurs in fluids (liquids and gases). When a fluid
is heated, it expands. The fluid then becomes less dense
and rises. The warm fluid is replaced by cooler/denser fluid.
- Convection occurs when the more energetic
particles move from the hotter region to the
cooler region and take their heat energy with
them
- EVAPORATION AND CONDENSATION
- The rate of condensation increases if the temperature of the gas is
decreased. On the other hand, the rate of evaporation increases if
the temperature of the liquid is increased.
- It is also increased if the surface area of the liquid is increased ans
air is moving over the surface of the liquid
- ENERGY TRANSFER BY DESIGN
- The greater the temperature difference
between an object and its surroundings, the
greater the rate at which that energy is
transferred.
- Sometimes we want to maximise the
rate of energy transfer to keep things
cool.
- SPECIFIC HEAT CAPACITY
- When we heat a substance, we transfer energy
to it so the overall temperature is increased.