Zusammenfassung der Ressource
Physics Topic 6 -
Energy and The Future
- Energy
Transfers
- Thermal (heat energy), Light, Electrical, Kinetic
(movement energy), Sound, Chemical Potential
(such as the energy stored in batteries and fuels).
- There are nine forms of energy.
- Nuclear Potential (the energy
stored in the nuclei of atoms),
Gravitation Potential (the energy
stored in things that can fall).
- Elastic Potential (the energy stored by
things that have been stretched or
squashed and can spring back).
- Energy can be moved from
one place to another, this is
called Energy Transfer. When
this happens, energy often
changes from one form to
another.
- Output Energy = Input Energy
- Energy Conversion
Diagrams (sometimes
known as a Sankey Diagram).
- This diagram shows the amount of
energy converted or transferred. The
width of the arrows represents the
amount of energy in joules.
- Efficiency
- Efficiency means how
good a device is at
converting energy into
useful forms is known
as its efficiency.
- useful energy transferred by the device
---------------------------------------------------- x 100%
total energy supplied to the device
- Efficiency =
- Household goods are given
an energy rating. Rather thatn
give these as percentages,
they are given as a colour
coded grade from 'A' to 'G'.
- With 'A' being the
most efficient.
- Heat Radiation
- Some surfaces are better
emitters of radiation that others.
- A good absorber of heat is also a
good emitter of heat.
- Black is the best colour at absorbing thermal
energy and black is also a good emitter.
- The Earth's Temperature
- The Earth's surface absorbs about
half of the radiation that reaches
the Earth and re-radiates the
energy as infra-red radiation.
- Which can heat up the atmosphere.
- For the temperature of the Earth
to stay the same, it must radiate
energy into space at the same
average rate as it absorbs it.
- Too much
greenhouse
gas is bad
for the
atmosphere
as it
increases
our carbon
footprint.
- But if all the greenhouse gases are removed from the
atmosphere, the atmosphere will be able to hold less
energy and it's temperature will decrease.