+ Energy Transfer Noadswood Science, 2011

+ Energy Transfer To understand energy transfers, and to be able to draw sankey diagrams Friday, August 07, 2015

+ Energy What is energy? What types of energy are there?

+ Energy Energy is the ability to ‘do some work’ - everything that happens needs energy (e.g. heating; cooking; lighting; movement of vehicles; and keeping us alive)! Energy cannot be created or destroyed, only transferred from place to place in a variety of ways

+ Types Of Energy Electrical energy - a current in a circuit etc… Light energy - from the sun; a light bulb etc… Sound energy - from a loudspeaker; a drum etc… Kinetic (movement) energy - anything which moves! Nuclear energy - transferred during a nuclear reaction Thermal (heat) energy - transferred from hot objects to colder ones Radiant heat (infra red) energy - transferred as electromagnetic radiation by hot objects Gravitational potential energy - possessed by anything with the ability to fall Elastic potential energy - stretched springs; elastic and rubber bands etc… Chemical energy - possessed by food; fuels; batteries etc…

+ Energy Newton’s Cradle – example of energy being transferred…

+ Experiment Your task is to move around each of the stations, answering the questions at each point (you have 3 minutes per station)… Stations: - Signal generator Microphone Kettle with windmill Air bazooka Fire Slinky Cordless screwdriver Hair straighteners

+ Signal Generator What are the energy transfers for the signal generator? Electrical  Light / Sound Which forms of energy are wasted? Heat through circuits How could you make it more efficient? Better insulated wires etc… Are there still energy transfers taking place, even when you cannot hear the sound? Yes – visual as well as heat transfer through circuitry + sounds which our ears are unable to detect

+ Microphone What are the energy transfers for the microphone? Sound  Electrical Which forms of energy are wasted – where do these go? Heat through circuitry to surroundings How could you make it more efficient? Better insulated; more sensitive cone which will not waste as much energy Can you think of any other devices which use these energy transfers? Opposite found in loudspeakers; our own ears transfer sound energy into electrical impulses

+ Kettle & Windmill What are the energy transfers for the kettle and windmill? Chemical  Electrical  Heat  Kinetic  Electrical Which forms of energy are wasted – where do these go? Heat to surroundings; sound to surroundings through windmill movement How could you make it more efficient? More aerodynamic windmill; insulated kettle to stop heat loss This is very similar to how electricity is generated – can you think how you could use this method to make electricity? Generator connected to windmill transferring kinetic to electrical

+ Air Bazooka What are the energy transfers for the air bazooka? Potential  Kinetic Which forms of energy are wasted – where do these go? Heat and sound to surroundings How could you make it more efficient? Energy store could be more efficient; delivery system pushing missle out Can you think of any other devices which use these energy transfers? Steam catapults on aircraft carriers; bullets (chemical stores)

+ Fire What are the energy transfers for using sticks to make fire? Chemical  Heat Which forms of energy are wasted – where do these go? Light and sound to surroundings How could you make it more efficient? Different fuel to burn more efficiently (i.e. petrol over wood) Why is it important to make things more energy efficient? Ensures we get best value for money from fuel – most fuels are non-renewable so we need to get the most from them that we can / less fuel = more environmentally beneficial

+ Slinkey What are the energy transfers for a slinky falling down some stairs? Gravitational potential (elastic potential)  Kinetic Which forms of energy are wasted – where do these go? Sound to surroundings and some heat through movement / friction How could you make it more efficient? Stop springs colliding causing sound Can you think of another device which uses these energy transfers? Hydroelectric power relies on gravitational potential to kinetic

+ Cordless Screwdriver What are the energy transfers for the cordless screwdriver? Electrical  Kinetic Which forms of energy are wasted – where do these go? Sound and heat to surroundings How could you make it more efficient? Improved motor with less frictional loss (heat loss) Can you think of any other devices which use these energy transfers? Remote control cars; watches etc…

+ Hair straighteners What are the energy transfers for the hair straighteners Electrical  Heat Which forms of energy are wasted – where do these go? Sound; heat loss through the non-contact points How could you make it more efficient? Better conductivity of materials Why do you think some straighteners are better than others? Dependent upon conductivity of material at point of contact with hair – better conductors heat up quicker and transfer their energy to the hair quicker and more effectively

+ Energy Transfer Different types of energy can be transferred from one type to another Energy transfer diagrams show each type of energy, whether it is stored or not, and the processes taking place as it is transferred

+ Energy Transfer Different types of energy can be transferred from one type to another Energy transfer diagrams show each type of energy, whether it is stored or not, and the processes taking place as it is transferred

+ Sankey Diagrams Sankey diagrams show the relative amounts of each type of energy They summarise all the energy transfers taking place in a process – the thicker the line or arrow, the greater the amount of energy involved Sankey diagram of a light bulb

+ Wasted Energy can be 'wasted' during energy transfers Energy cannot be created or destroyed, only transferred from one form to another Energy that is ‘wasted’ (e.g. heat energy from an electrical lamp) does not disappear – instead it is transferred to the surroundings, spreading out so much that it becomes difficult to do anything useful with

+ Lamps - Ordinary Ordinary electric lamps contain a thin metal filament that glows when electricity passes through it – however, most of the electrical energy is transferred as heat energy instead of light energy: -

+ Lamps – Energy Saving Modern energy-saving lamps work in a different way – they transfer a greater proportion of electrical energy as light energy: -