Chapter 15: Temperature, Heat and Expansion Flashcards
Lecture Slide only
Temperature
A quantity/number that corresponds to the warmth of an object
Temperature related to the random motions of
Atoms and molecules in a substance
Temperature measured by a
Thermometer
Temperature have no
Upper limit
Temperature definite limit on
Lower end
Temperature is proportional to
The average translational kinetic energy per particle in a substance
High temperature of an object is equal to higher
Average kinetic energy of its particle
Solid particles were
Vibrate and jiggle in place
Liquid particles were
Slide and jiggle past one another
Gas particle bounce
Back and forth
Liquid thermometer
Measures temperature by expansion or contraction of a liquid
Liquid thermometer usually have
Mercury or colored alcohol and having high boiling points and high coefficients of expansion
Temperature reading occurs when the thermometer and the object reach
Thermal equilibrium
Temperature equal temperature number no more
Heat flow and same average kinetic energy per particle
Infrared thermometers operate by
Sensing IR radiation and use lens to focus IR light from object to a detector
Temperature Scales
1) Celsius Scale
2) Fahrenheit Scale
3) Kelvin Scale
1) Celsius Scale
0 degree for freezing point of water to 100 degrees for boiling point of water
2) Fahrenheit Scale
32 degrees for freezing point and 212 degrees for boiling point
3) Kelvin Scale
1) Measured in K, not degrees
2) 273 K for freezing point and 373 for boiling point
3) 0 at absolute zero temperature at which there is no energy left to give up or transfer to another substance
There is twice as much molecular kinetic energy in 2 liters of boiling water as in 1 litter of boiling water. Which will be the same for both?
A. Temperature
Heat
Energy transferred from one object to another due to a temperature difference
Heat direction and flow of energy transfer is
Always from a warmer object to a neighboring cooler object
Touch a hot stove, energy transfer from the stove to
The hand
Touch a piece of ice, energy transfer from the hand to
Ice
Work done by friction goes into
Heating an object called this: “Thermal energy” to make clear its link to heat and temperature
Refer to thermal energy as
Internal energy (U) and the grand total of all the energies inside a substance
Translational, rotational, and vibrational energy of molecules that make up a
Substance
A substance does not contain heat, it contains
Internal energy
If a red hot thumbtack is immersed in warm water and the direction of heat flow will be from the
Red-hot thumbtack to the warm water
Heat (quantity of heat) measured in
Joules (J) and Calories (J/C degrees), and 4.18 joules of heat are required to change the temperature of 1g of water by 1 Celsius degree
Heat energy ratings of food are determined by
Energy released when burned
Heat sample of food is placed in
Insulated, oxygen-filled chamber, and surrounded by water
Heat sample burned
Completely and heat from burning increases temperature of the water
Heat temperature is measured and indicated the number of
Calories in the food
The same quantity of heat is added to different amounts of water in two equal size containers. Assume the initial temperature is the same. The temperature of the smaller amount of water.
Increases more
Specific heat capacity
The quantity of heat required to change the temperature of a unit mass of the substance by 1 degree Celsius
Specific heat capacity is the same for thermal inertia
The tendency of something to resist changes in the temperature
The greater the specific heat capacity of a substance, the more energy it takes to change its
Temperature
Specific heat capacity if given different substances will have
Different thermal capacities for storing energy
Equal masses of different materials require different quantities of heat to
Change their temperatures by a given amount
1 g of water 1 calorie to raise temperature
1 degrees Celsius
1 g of iron requires 1/8 as much energy for the same
Temperature increase
Water absorbs more heat than iron for the same change in
Temperature
Water has a
Higher specific heat
Water molecules have
Strong intermolecular bonds so it takes a significant amount of energy to separate them
Strong intermolecular bonds equal to
Strong attraction
Which has the higher specific heat capacity, water or land?
Water
The high specific heat capacity of water application of
High capacity for water and sea breeze
Formation of sea breeze (air layer above land is)
Warmer, less dense, and creates a low pressure system above land
Formation of sea breeze (air layer above water is)
Cooler, denser, and creates a high pressure system above water
Pressure difference causes
Cool air above water (at high pressure) to flow above land (at lower pressure) - Sea Breeze
Formation of land breeze (air layer above land is)
Cooler, denser, and creates a high pressure system above land
Formation of land breeze (air later above water is)
Warmer, less dense, and creates a low pressure system above water
Pressure difference causes
Cool air above land (at high pressure) to flow above water (at lower pressure) - Land Breeze
Liquid cooling is
A highly effective method of removing excess heat from CPUs
Liquids allow the transfer of more heat from the parts being cooled than air, making liquid cooling suitable for
High performance computer applications
Thermal expansion
Increasing the temperature of a substance increases the motion of molecules and jiggle faster and move farther apart
Most substances expand when heated and contract when
Cooled
Warming metal lids on glass jar under hot water loosens the lid by
Expansion
Thermal expansion/contraction plays a role in
Construction and devices
Use of reinforcing steel with the same rate of expansion as
Concreate expansion joints on bridges
Gaps on concrete roadways and sidewalks allow for
Concrete expansion in the summer and contraction in the winter
Bimetallic strips
Two strips of different metals welded together
Bimetallic strips are used in
Heater, oven thermometers, refrigerators, and electric toasters
Brass expands more when heated than iron does and contracts more when
Cooled and because of it, the strip bends
Water expands when heated (like most substances) and it does not
Expand in the range between 0 degree and 4 degrees
When water become ice, it is
Expand
Ice has open-structured crystals resulting from strong bonds at certain angles that increase its
Volume and this make ice less dense than liquid water
As temperature of water at 0 degrees increases, two opposite processes occur
Contraction and expansion
Ice crystals collapse plus heating of liquid water molecules were affecting the contracting and collapsing on
Dominates until the temperature reaches 4 degrees Celsius
Expansion overrides contraction because most of the ice crystals have
Melted into water
Between 0 degree and 4 degrees Celsius, the volume of liquid water decreases as the temperature
Increases
Above 4 degrees Celsius, water behaves the way other substances do; Its volume increases as its temperature
Increases
When ice freezes to become solid ice, its volume increases tremendously about what percent?
9%
Density of ice at any temperature is much lower than the density of water, this is why the ice was
Float in water
When sample of 0 degree water is heated, its first
Contracts
When a sample of 4 degrees water is cooled, it is
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