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14 Cards in this Set
- Front
- Back
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WHAT IS CONVECTION? |
Convection occurs when the more energetic particles move from a hotter reigon to a cooler reigon and take the energy with them. |
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WHY CAN CONVECTION NOT OCCUR WITHIN A SOLID? |
Convetion cannot occur within a solid as the particles cannot move - they just vibrate on the spot. |
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HOW DOES CONVECTION WORK? |
When you heat a liquid or gas, the particles move faster, and the fluid expands becoming less dense. The warmer, less dense fluid rises above its colder surroundings. As the warm fluid rises, cooler fluid takes its place. |
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WHAT IS CONDUCTION? |
Condution of heat is the process where vibrating particles pass on extra kinetic energy to neighbouring particles. |
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WHY ARE PLASTIC HANDLES BETTER THAN METAL HANDLES? |
Plastic handles are poor conductors of heat but good insulators, they don't have free electrons like metals so heat up more slowly therfore making them safe for personal use. |
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HOW DOES CONDUCTION WORK? |
In a solid, the particles are held tightly together. So when one particle vibrates, it bumps into a neighbouring particle making them vibrate. Particles which vibrate faster than others pass on their kinetic energy to neighbouring particles. This causes a rise in temperature on the other sider. |
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WHAT IS HEAT RADIATION? |
All objects continually emit and absorb heat radiation. The hotter an object the more radiation it radiates in a given time. |
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COMPARE BLACK AND WHITE SURFACES |
Black and matt surfaces are good emitters of infra-red radiation it also absorbs radiation. On the other hand, white and shiny surfaces reflect nearly all heat falling on them they are poor emitters of heat energy. |
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WHAT IS CONDENSATION? |
Condensation is when a gas turns to a liquid. When a gas cools, the particles in the gas slow down and lose kinetic energy. The attractive forces between the particles pull them closer together. |
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WHAT IS EVAPORATION? |
Evaporation is when a liquid turns to a gas. Particles can evaporate from a liquid at temperatures that are much lower than its boiling points. |
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HOW IS EVAPORATION MADE FASTER? NG LINE |
There are four main factors - 1. Temperature is higher 2. Density is lower 3. Surface area is higher 4. Airflow over the liquid is greater |
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HOW IS CONDENSATION MADE FASTER? |
There are four main factors - 1. Temperature of the gas is lower 2. Airflow is less 3. Temperature of the surface the gas touches is lower. 4. Density is higher |
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WHAT IS HEAT A MEASURE OF? |
Heat is a measure of energy. |
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