Heat and Temperature: Topics 4-6 Flashcards
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Substances increase in volume
contract
Substances shrink or decrease in volume
Solids
Has both a definite volume and shape
Liquid
Has definite volume but no definite shape
Gas
Has neither a definite volume or shape
Expansion and contraction of solids
The same substance will contract and expand at the same rate. Some solids expand and contract more than others.
Expansion and contraction of gases
Particles in gases are the farthest apart, allowing them to expand and contract the most out of any other state of matter.
Expansion and contraction of liquids
Liquids expand as they warm and contract as they cool, same as the other states of matter. Not all liquids expand and contract at the same rate, but in general liquids expand and contract more than solids and less than gases.
Heat Capacity
Amount of thermal energy that warms or cools the object by one degree Celsius. Depends on the mass of the object and material the object is made of.
Specific heat capacity
Amount of thermal energy that warms of cools one gram of a material by one degree Celsius. Depends on the material that the object is made of
Changes of state
Any pure substance can exist in all three states of matter. Substances can change state by being warmed or cooled
Melting/Fusion
Change of state from a solid to a liquid
Freeze/Solidification
Change of state from a liquid to a solid
Evaporate
Change of state from liquid to gas
Condense
Change of state from gas to liquid
Sublimation
Change of state from gas to solid or solid to gas
Evaporative Cooling
As a liquid heats up the high energy particles evaporate and the remaining liquid cools. The cool liquid then cools the surface on which it is resting.
Examples of evaporative cooling
Joggers feel cold as their clothes dry out after getting soaked in a rainstorm
Spraying the roof of a house to cool it off on a hot summer day
Placing a wet cloth on someones forehead to bring down their fever
Particle movement in solids
Particles have a regular arrangement and are close together. They vibrate in a fixed spot
Particle movement in liquids
Particles move freely but are held together loosely. They vibrate and rotate but often collide with each other because they are close together
Particle movement in gases
Particles move independently and are very far apart from each other.
Energy source
An object or material that can transfer its energy to other objects
Radiation
The transfer of energy without any movement of matter
Radiant energy
Energy that is transferred through radiation. Travels and behaves like a wave.
Electromagnetic radiation (EMR) Examples
Examples include: radio waves, microwaves, visible light, and X-rays
Thermal conduction
The process of transferring thermal energy through direct collisions between particles. Most commonly occurs in solids.
Heat conductors
Materials that speed up the transfer of thermal energy to or from the surroundings. Examples: metals, gold, copper
Heat insulators
Materials that slow down the transfer of thermal energy to or from the surroundings. Examples: glass, wood
Fluids
Materials that can be poured or that flow from place to place.
Convection
A warm fluid moves from place to place, carrying thermal energy with it
Convection current
A flow resulting from the rising of warm materials and the sinking of cool materials. (Heat up, cool down)
