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temperature |
measure of the average transitional kinetic energy per molecule of a substance, measured in degrees Celsius or Fahrenheit, or in kelvins |
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Who invented the first thermometer? |
Galileo |
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absolute zero |
The lowest possible temperature at which a substance has absolutely no kinetic energy to give off. |
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heat |
the energy transferred from one object to another |
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internal energy |
the grand total of all energies inside a substance |
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specific heat capacity |
quantity of heat required to raise the temperature of a unit mass of a substance by 1 degree Celsius (or equivalently, by 1 kelvin); often simply called specific heat |
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Why does a penny become warmer when it is struck by a hammer? |
kinetic energy |
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What is the temperature for freezing water on the Celsius scale? |
0 degrees |
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What is the temperature for freezing water on the Fahrenheit scale? |
32 degrees |
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What is them temperature for boiling water on the Celsius scale? |
100 degrees |
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What is the temperature for boiling water on the Fahrenheit scale? |
212 degrees |
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What is the temperature for freezing water on the Kelvin scale? |
0 degrees |
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What is the temperature of the boiling point of water on the Kelvin scale? |
100 degrees |
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What is meant by "translational" kinetic energy? |
motion that carries the molecule from one place tonanother |
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Which defines temperature-translational kinetic energy, rotational kinetic energy, vibrational kinetic energy, or all of these? |
translational kinetic energy |
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What is meant by the statement that a thermometer measures its own temperature? |
when a thermometer is in thermal contact with something whose temperature we wish to know, energy will flow between the two until their temperatures are equal and thermal equilibrium is established |
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When you touch a cold surface, does cold travel from the surface to your hand or does energy travel from your hand to the cold surface? Explain |
When you touch a cold surface, the cold travels from your hand to the cold surface. Transferred energy always travels from the warmer object to the colder object. |
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Distinguish between temperature and heat. |
temperature is the measure of the average translational kinetic energy per molecule in a substance measured in degrees Celsius, or Fahrenheit or kelvin. Heat is the energy that flows from a substance of lower temperature, commonly measured in calories or joules. |
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Distinguish between heat and internal energy. |
heat is the energy transferred from one object to another and internal energy is the grand total of all energies inside a substance |
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What determines the direction of heat flow? |
heat always flows from high-temperature to low-temperature |
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How is the energy value of food determined? |
Calories |
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Distinguish between a calorie and a Calorie. |
a calorie is the amount of heat required to the temperature of 1 gram of water by 1 Celsius degree. a Calorie is the value of energy in food |
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Which warms up faster when heat is applied-iron or silver? |
silver |
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Does a substance that heats up quickly have a high or low heat capacity? |
low specific heat capacity |
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Does a substance that cools off quickly have a high or low specific heat capacity? |
low specific heat capacity |
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How does the specific heat capacity of water compare with the specific heat capacity of other common materials? |
Water has one of the highest specific heat capacities known. But there are a few materials with higher specific heat capacities. |
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Northeastern Canada and much of Europe receive about the same amount of sunlight per unit area. Why then, is Europe generally warmer in the winter? |
The Gulf Stream moves warm water from the Caribbean to Europe’s North Atlantic coast. The water keeps most of its internal energy long enough for it to get there and when it arrives it cools. The energy released from the water, transfers to the air and the westerly winds carry it over the rest of Europe. |
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According to the law of conservation of energy, if ocean water cools, something else should warm. What is it that warms? |
the land |
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Why is the temperature fairly constant for land masses surrounded by large bodies of water? |
because water moderates temperature extremes |
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Why do substances expand when temperature is increased? |
because when a substance’s temperature increases, its molecules or atoms jiggle faster and move farther apart. Thermal expansion is the result. |
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Why does a bimetallic strip bend with changes in temperature? |
because when it is heated one side of the strip becomes longer than the other causing the strip to bend and when it’s cooled the side of the strip that becomes longer when heated shrinks causing the strip to bend in the opposite direction |
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Which generally expands more for an equal increase in temperature-solids or liquids? |
liquids |
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When the temperature of ice-cold water is increased slightly, does it undergo a net expansion or a net contraction? |
net contraction |
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What is the reason for ice being less dense than water? |
water molecules in a liquid are closer together than water molecules frozen in ice, where they have an open crystalline structure |
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Does "microscopic slush" in water tend to make it more dense or less dense? |
less |
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What happens in the amount of "microscopic slush" in cold water when its temperature is increased? |
it melts |
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At what temperature do the combined effects of contraction and expansion produce the smallest volume for water? |
4 degrees Celsius |
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Why does water in a lake have to be cooled to 4 degrees Celsius before surface water can be cooled below 4 degrees Celsius? |
Because of water’s high specific heat capacity and poor ability to conduct heat |
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Why does ice form at the surface of a body of water instead of the bottom? |
because water at 0 degrees Celsius is less dense and "floats" at the surface |
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Conduction |
the transfer of heat energy by molecular and electron collisions with a substance (especially a solid). |
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Convection |
the transfer of heat energy in a gas or a liquid by means of currents in the heated fluid. The fluid moves, carrying energy with it. |
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Radiation |
the transfer of energy by means of electromagnetic waves |
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Terrestrial radiation |
the radiation emitted by Earth to outer space |
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Newton’s law of cooling |
the rate of loss of heat from a warm object is proportional to the temperature difference between the object and its surroundings. (Similarly for the gain of heat by a cooled object.) |
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Greenhouse effect |
Warming of the lower atmosphere by short-wavelength radiation from the Sun that penetrates the atmosphere is absorbed by Earth and is radiated at longer wavelengths that cannot easily escape Earth’s atmosphere. |
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Solar constant |
1400 J/m^2 received from the Sun each second at the top of Earth’s atmosphere |
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Solar power |
Energy per unit derived from the Sun |
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What is the role of "loose" electrons in heat conductors? |
they conduct heat and electricity well and if the conductor has "loose electrons" in it it will be a good conductor of heat |
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If you touch the metal sides inside of an oven with a bare hand, you’re in trouble. But hold your hand briefly in the oven air and you’re okay. What does this tell you about the relative conductivities of metal and air? |
metal is a excellent conductor of heat and air is a poor conductor of heat |
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Explain why a firewalker can step quickly without harm on red-hot coals with bare feet. |
wood is a poor conductor of heat even when very hot and even though the temperature of them may be high relatively little heat is conducted to the feet |
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Why are such materials as wood, fur feathers, and even snow good insulators? |
because they have many small air spaces |
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Does a good insulator prevent heat from escaping, or does it simply slow its passage? |
slow its passage |
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What happens to the volume of air as it rises? What happens to its temperature? |
The volume becomes more and more dense until its density matches that of the surrounding air. The temperature cools. |
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When an air molecule is hit by an approaching faster-moving molecule, does its rebound speed increase or decrease? How about when it hits a receding molecule? |
when its hit by an approaching faster-moving molecule its rebound speed increases. when it hits a receding molecule its speed decreases |
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How are the speeds of molecules of air affected when the air is compressed by the action of a tire pump? |
it increases |
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Why is Millie’s hand not burned when she holds it above the escape valve of the pressure cooker? |
the hot steam expands and is cool to Millie’s touch |
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Why does the direction of coastal winds change from day to night? |
during the day, warm air above the land rises, and cooler air over the water moves to replace it at night the direction of air flow is reversed because then the water is warmer than the land |
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In what form does radiant energy travel? |
electromagnetic waves |
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Relatively speaking, do high-frequency waves have long wavelengths or short wavelengths?relate to the |
short wavelengths |
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How does frequency of radiant energy to the absolute temperature of the radiating source? |
the peak of frequency of radiant energy is directly proportional to temperature absolute of the radiating source |
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Cite a primary difference between waves of solar radiation and waves of terrestrial radiation. |
the Sun’s glow is visible to the eye; Earth’s glow consists of longer waves and isn’t visible to the eye |
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Since all objects emit energy to their surroundings, why don’t the temperatures of all objects continuously decrease? |
because everything is also absorbing energy |
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What determines whether an object is a net absorber or a net emitter of radiant energy at any given time? |
whether its temperature is above or below its surroundings |
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Which will normally warm faster-a black pot of cold water or a silvered pot of warm water? Explain. |
a black pot of cold water. blackened things are better absorber and emitter than silvered things |
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Can an object be both a good absorber and a good reflector at the same time? Why or why not? |
no, because absorption and reflection are opposite processes |
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Why does the pupil of the eye appear black? |
because it allows light to enter with no reflection |
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What happens to the temperature of something that radiates energy without absorbing the same amount in return? |
it becomes cooler |
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An object radiating energy at night is in constant contact with the relatively warm Earth. How does its conductivity affect whether or not it becomes appreciably colder than the air? |
if its a poor conductor little heat is conducted to it from the ground and it becomes colder but if its a good conductor than heat conducts to the ground and stabilizes its temperature |
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Which will undergo the greater change in cooling – a red-hot poker in a warm oven or a red-hot poker in a cold room (or do they both cool at the same rate)? |
a red-hot poker in a cold room |
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Does Newton’s law of cooling apply to warming as well as to cooling? |
yes |
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What would be the consequence of completely eliminating the greenhouse effect? |
the Earth would be -18 degrees Celsius and frigid |
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In what ways does glass act like a one-way valve for a conventional greenhouse? Does the atmosphere play the same role? |
short-wavelength radiation from the Sun transmitted through the glass but long-wavelengths reradiated energy is not transmitted out through the glass and is trapped inside |
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How much radiant energy from the Sun, on average reaches each square meter at the of Earth’s atmosphere? |
1400 J |
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What is the function of a photovotalic cell? |
they convert light energy directly to electrical energy |
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Cite three ways in which a Thermos bottle inhibits heat transfer. |
1. Heat transfer by conduction through the vacuum is impossible. 2. The vacuum has no fluid convect, so there is no heat loss through the walls by convection. 3. Heat loos by radiation is reduced by silvered surfaces of the walls, which reflect heat waves back into the bottle. |
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