P1 Energy Flashcards
Where is energy stored when transferred
When energy is transferred to an object, the energy is stored in one of the objects energy stores
Name the energy stores
Thermal Kinetic Gravitational potential Elastic potential Chemical Magnetic Electrostatic Nuclear
What happens when a system changes
Energy is transferred into or away from the system between different objects or different energy stores
What’s a system
Single object/group of objects
Describe the energy transfer in a boiling kettle
Energy is transferred to the water by heating into the waters thermal energy store
What is the kettle and water known as
Two object system
What is work done the same as
Energy transferred
How can work be done
Work Can be done when current flows (work done against resistance in a circuit) or by a force moving an object
Work done when a car breaks
The friction between the cars breaks and wheels does as it slows it down
How is work done when a ball is dropped
Dropped ball is accelerated by gravity and gravitational force does work as it causes energy transferred from the balls gravitational potential energy store onto its kinetic energy store
What does movement mean
Movement means energy is in an objects kinetic energy store
What happens with energy when an object speeds/slows
Speed up - more energy given
Slows down - energy transferred away
What do raised objects store
Store energy in gravitational potential energy stores
What does lifting an object require
Lifting object in gravitational field requires work (energy transfer) higher object = more energy
What happens when an object falls
GPE store transfers energy to the kinetic store.
Energy lost in GPE = energy Gained in kinetic energy
What does air resistance cause
Causes energy to be transferred to another store e.g thermal
What does stretching an object transfer
Transfers energy to elastic potential energy stores
Equation for elastic potential energy
1/2 x spring constant x extension squared
What is the specific heat capacity
It’s the amount of energy needed to raise the temperature of 1kg of a substance by 1 degree
What do different materials have
Different specific heat capacities.
More energy transferred to thermal energy stores of some materials to increase temperature and transfer loads to cool down
What’s the conservation of energy principle
Is that energy is always conserved.
Energy can be transferred usefully, stored or dissipated but can’t be made or destroyed
How is energy transferred to a phone
Energy usefully transferred from chemical energy to battery. Some is dissipated Into thermal store
What is power
The rate of doing work
What’s a closed system
A closed object where no energy can escape or be added - no energy leaves system.
E.g cold spoon dropped into insulated flask of hot soup. Energy transferred from thermal store of soup to cold spoon
One watt =
1 joule of energy transferred per second
What does a powerfully machine do
Transfers lot of energy in a short space of time
What happens if two cars race the same distance but one car has a powerfuler engine
Car that’s more powerful will finish first. They both transfer the same energy, but the more powerful one does so in less time
What do lubricants do and how
They reduce friction by making the surface slippy as they flow easily
What does insulation do
Reduces rate of transfer by heating
Thick walls with preventing heat energy loss
Walls made from low thermal conductivity material - slow rate of heat transfer
What are cavity walls
Inner and outer wall with gap in middle so it reduces energy. Transferred by conduction
What is loft insulation
Reduces convection current. (Cycle where Particles are constantly heated, rising, cooling then sinking
What do draught excluders do
Around doors and windows and reduce convection
What is conduction
When an object is heating and energy is transferred to its particles kinetic energy store. Particles vibrate and collide more and transfer energy to the rest of the object
What is convection
When liquids or gases are heated they become less dense (as they can flow) they rise into the cooler denser regions and the denser liquid/gas falls into the less dense liquid/gas and warms up
What is thermal conductivity
How quick energy is transferred through a metal
What happens if a material has a higher thermal conductivity
Transfers energy between particles quicker
If particles can move, they move faster and the space between particles increases and causes density. (Region being heated decreases)
How to improve efficiency of energy transfers
Insulating objects, lubricating or making more streamlined
Why are useful devices useful
They transfer energy from one store to another. Some input energy is wasted
What is efficiency
Measure of how much energy transferred is conserved in the process
What’s a non renewable resource
Runs out (fossil fuels or nuclear fuel)
What are fossil fuels and examples
Natural resources that formed underground millions of years ago
Coal oil gas
What’s a renewable resource and examples
Won’t run out
Solar, wind, water, hydroelectricity
Biofuels, tides
Most do damage environment but not too bad. Don’t provide lots of energy
Example of how non renewable resources used
Petrol and diesel powered vehicles. Fuel from oil
Coal used in steam trains or fire places
Gas used to heat water pumped into radiators
How renewable resources are used
Vehicles run on bio fuels
Geothermal heat pump uses geothermal energy resources to heat building
Solar water heaters - sun heats water pumped into radiators
About wind power
Work most of time. Dependent on weather
Have a generator inside with rotating blades that turn a generator
Spoil the view
Don’t create a lot of energy
About solar cells
Expensive but no pollution
Depends on weather
Best for calculators or watches
Generates on small scale
About geothermal power
Energy in underground thermal energy stores. In volcanic areas or hot rocks near surface
Source of energy is the slow decay of radioactive elements
Reliable
Not many places
About hydro electric power
No pollution. Requires flooding a valley by building dam. - big impact on environment(rotting vegetation causes CO2 and methane. Loss of habitat)
Provides high demand. High initial cost
About wave power
Lots of small wave powered turbines around coast. Connected to generator.
No pollution but disturbs sea bed and habitat of marine animals.
Hazard to boats
Unreliable when wave stops when wind dies down
Low running costs
Good for small areas
About tidal barrages
No pollution
Dams built across river with turbines in the. Tide comes in and fills estuary and water through turbines.
Boats can’t get past, spoils view and alters wildlife
Tides reliable as they happen twice a day
Low tide = less energy
High initial costs
Provide significant energy
About biofuel
Made from plants and waste.
Renewable as it’s made from plant products or animal waste
Reliable as crops grow quickly and can be grown all year round. Can’t supply demands
Forest cleared to grow biofuels = loss of habitat and burning means CO2 AND methane
About non renewable
Reliable and meet current demands.
Running out
Power plants initially costly
Cost effective way to produce energy due to low fuel extraction costs
How do non renewable create environmental issues
When burned, CO2 and methane released. Adds to greenhouse effect and global warming
Burning coal and oil releases Sulphur dioxide and creates acid rain which is harmful to trees and soil
Coal mining harms landscape
Oil spillage
Nuclear power is clean, nuclear waste dangerous and hard to dispose
Why is renewable resources limited by reliability money and politics
Will the resources be reliable
New power plants are costly ans energy providers are reluctant
Causes bill increase and some can’t afford
Arguments where to build
Personal changes are expensive
