Presentation on theme: "Conduction Noadswood Science, 2011. Conduction To understand conduction and be able to explain why some materials are better conductors than others Sunday,"— Presentation transcript:
Conduction To understand conduction and be able to explain why some materials are better conductors than others Sunday, April 26, 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 1.Electrical energy - a current in a circuit etc… 2.Light energy - from the sun; a light bulb etc… 3.Sound energy - from a loudspeaker; a drum etc… 4.Kinetic (movement) energy - anything which moves! 5.Nuclear energy - transferred during a nuclear reaction 6.Thermal (heat) energy - transferred from hot objects to colder ones 7.Radiant heat (infra red) energy - transferred as electromagnetic radiation by hot objects (how the energy from the Sun gets to the Earth) 8.Gravitational potential energy - possessed by anything with the ability to fall 9.Elastic potential energy - stretched springs; elastic and rubber bands etc… 10.Chemical energy - possessed by food; fuels; batteries etc… (how we get our energy)
Hot Food Look at the following saucepans and spoons – which are better to use when cooking and eating hot soup (think about using conduction / conduct in your answer)…
Cold Food Which spoon is better to use when eating cold ice cream?
Heat Transfer Why do ice cubes melt when you hold them? Ice cubes melt as heat flows from your hand to the ice cube, warming it up, changing its state from a solid to a liquid
Conduction Conduction of heat occurs mainly in solids Conduction is the process where vibrating particles pass on their extra kinetic energy to neighbouring particles
Conduction Conduction is the process where vibrating particles pass on their extra kinetic energy to neighbouring particles – this occurs better in solids rather than gases or liquids because the particles are very close together In metals the outer electrons are not attached to any particular atom, and are free to move between the atoms – these gain energy when the metal is heated moving through the metal quickly (this is why heat transfer is very efficient in metals)
Equal Conduction Are all metals equally good at conducting? Some metals conduct better than others – for example silver is a much better conduct than copper (however silver is much more expensive than copper, so it is not economically viable to use this)! The ability of a metal to conduct is largely due to either its ability for its atoms to bump into its neighbours or the ability for the free electrons to move around
Experiment 1 In your groups you are going to be given a set of rods made from different materials and of different lengths Your challenge is to decide which of these will be the best conductor… Write down your prediction for which metal will be the best conductor and why As you go through the experiment find out if everyone has got the same results as your groups – if not what may have caused these errors?
Experiment 2 In your groups you are going to be given a set of rods made from different materials This time your challenge is to decide which of these is made from copper Write down your hypothesis for how you will recognise which rod is made from copper As you go through the experiment find out if everyone has got the same results as your groups – if not what may have caused these errors?
Conduction In Nature Why do penguins huddle in groups in terms of heat conservation? Penguins huddle together as this allows some conduction of heat from one penguin to its neighbour…