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P1-3-Energy - Coggle Diagram
P1-3-Energy
Energy transfers in a system
what is the law of conservation of energy?
define dissipation
describe how in all system
changes energy is dissipated, so that it is stored in less useful ways (wasted)
picture on a television screen
printer
mobile phone
how can unwanted energy
transfers be reduced?
eg hot water tank
eg moving parts in a car
how does the rate of energy transfer by conduction across the material change with the
thermal conductivity
of a material?
describe how the rate of cooling of a building
is affected by the thickness and thermal conductivity of its walls.
National and global energy resources
Name the main energy resources available for use on Earth
what is the difference between energy resources that are
renewable
vs
non-renewable
?
why are some energy resources are more reliable than others?
describe the environmental impact arising from the use of different energy resources
compare ways that different energy resources are used for-
transport
heating
electricity generation
Energy stores and systems
what is a system?
what are the
four transfer methods
(HERM)
describe the changes in
energy stores
for the following
an object projected upwards eg throwing a ball upwards
a moving object hitting an obstacle eg a squash ball hitting a wall
an object accelerated by a constant force eg a car accelerating
a vehicle slowing down
bringing water to a boil in an electric kettle
Changes in energy
what is the equation for KE and name the units?
what is the equation for EPE and name the units?
what is the equation for GPE and name the units?
Energy changes in systems
Required practical activity 14:
an investigation to determine the specific heat capacity of one or more materials. The investigation will involve linking the decrease of one energy store (or work done) to the increase in temperature and subsequent increase in thermal energy stored.
what is specific heat capacity?
what is the equation linking change in thermal energy and specific heat capacity and name the units?
Power
what are the
two
equations for power and name the units?
1.
2.
Note:
an energy transfer of 1 joule per second is equal to a power of 1 watt
give examples that illustrate the definition of
power
eg comparing two electric motors that both lift the same weight
through the same height but one does it faster than the other
eg an LED bulb has a power rating of 8W, a halogen bulb has a power rating of 28W but they both have a similar brightness. What is the difference?
Efficiency
what are the
two
equations for efficiency?
1.
2.
describe ways to increase the
efficiency of an intended energy transfer
eg which lorry is more efficient and why?
