Physics 1.1-9
- Created by: Sam Musgrove
- Created on: 23-03-13 10:08
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- Energy Transfer By Heating
- Conduction
- Conduction in a metal is mainly due to free electrons transferring energy inside the metal
- Materials such as wool and fibreglass are good insulators
- Non-metals are poor conductors because they do not contain free electrons
- Metals are the best conductors
- Specific Heat Capacity
- The rate of temperature change in a substance when heated depends on the energy transferred to it, its mass and its specific heat capacity
- The greater the mass of an object, the more slowly its temperature increases when it is heated
- States of Matter
- The particles in a liquid move about at random and are in contact with each other
- The particles in a solid are held next to each other, vibrating in their fixed positions
- The particles in a gas move about randomly and are much farther apart than particles in a solid or liquid
- Flow, shape, volume and density are the properties used to describe each state of matter
- Heating and Insulated Buildings
- U-values tell us how much energy per second passes through different materials. The lower the U-value the better the material is as an insulator
- The rate of energy transfer to or from our homes can be reduced
- Solar heating panels don't use fuel to heat water but they are expensive to buy and install
- Convection
- Convection is the circulation of a fluid (liquid or gas) caused by heating it
- Heating a liquid or a gas makes it less dense so it rises and causes circulation
- Convection takes place only in liquids and gases (fluids)
- Energy Transfer by Design
- The rate of energy transfer to or from an object depends on:
- The materials the object is in contact with
- The shape, size and type of material of the object
- The temperature difference between the object and its surroundings
- The rate of energy transfer to or from an object depends on:
- Surfaces and Radiation
- Dark, matt surfaces emit infrared radiation more quickly than light, shiny surfaces
- Dark, matt surfaces absorb infrared radiation more quickly than light, shiny surfaces
- Light, shiny surfaces reflect more infrared radiation than dark, matt surfaces
- Infrared Radiation
- All objects emit infrared radiation
- Infrared red radiation is energy transfer by electromagnetic waves
- The hotter an object is the more infrared radiation it emits in a given time
- Evaporation and Condensation
- Condensation is when a gas turns into a liquid
- Evaporation is when a liquid turns into a gas
- Conduction
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