Ch. 22 test
good emitters of radiant energy are also good __
absorbers
define insulator
any material that is a poor conductor of heat and that delays the transfer of heat
when a molecule collides with a molecule that is receding, its rebound speed after the collision is __ than it was before the collision
less
suppose you have a box, painted white inside, which is closed except for a hole 2 centimeters wide. Circle the letter beside the sentence that explains why the hole appears black
light that enters is reflected and partly absorbed so many times that little is left to come out
objects of everyday temperatures emit waves mostly in the __ end of the infrared region
long-wavelength
do objects at low temperatures emit waves with a longer or shorter wavelength than objects with higher temperature?
longer
imagine stepping with one bare foot onto metal and with the other bare foot onto wood. Explain why the metal feels cool and the wood feels warm, even though they have the same temperature
metal is a good conductor, but wood is a poor conductor. heat easily moves out of your foot into the cooler metal. Little heat moves out of your foot into the wood, so your foot does not sense that it is touching something cooler
what are the best conductors
metals
an insulator cannot totally prevent heat from getting through, but instead just reduces the rate at which heat penetrates. true or false?
true
as air rises and expands, it collides with more molecules that are receding than are approaching. True of false?
true
conduction occurs without any overall transfer of matter. true or false?
true
__ is the main greenhouse gas
water vapor
convection currents stirring the atmosphere produce
winds
Light-colored objects reflect more light than dark-colored ones. true or false?
true
Newton's law of cooling also holds for heating. true or false?
true
order the different types of radiant energy from longest to shortest wavelength by placing a number from 1 to 7 beside each other
1 - radio waves 2 - microwaves 3 - infrared radiation 4 - visible light 5 - ultraviolet radiation 6 - X - rays 7 - gamma rays
on a sunny day, Earth's surface is a net __, and at night it is a net __
1. absorber 2. emitter
an object in thermal equilibrium is both __ and __ energy at the same rate
1. absorbing 2. radiating
air is transparent to both infrared (long) waves and visible (short) waves, unless the air contains excess __ and __
1. carbon dioxide 2. water vapor
type of radiant energy you feel as heat if you sit near a fireplace 1. infrared radiation 2. microwaves 3. ultraviolet 4. x-rays
1. infrared radiation
Glass is __ to visible light waves, but __ infrared waves
1. transparent 2. absorbs
__ is the gas most rapidly increasing in the atmosphere
CO2
use the figure above to explain Earth's global warming
Earth's atmosphere allows short waves from the sun to pass through. These waves strike Earth, which re-radiates the energy as longer waves. Atmospheric gases absorb and re-emit much of this long-wavelength radiation back to Earth
Explain, the two ways convection currents produced by uneven heating of Earth's surface produce sea breezes
a. during the day: the shore warms more easily than the water. Air over the shore rises, and cooler air from above the water takes its place, producing a breeze toward the land b. at night: the shore cools off more quickly than the water. Air over the water rises, and the cooler air from above the shore takes it place, producing a breeze toward the sea.
How do birds vary their insulation
by fluffing their feathers to create air spaces
I for insulator wood - i straw - i air - i cork - i wool - i paper - i polystyrene - i
c for conductor aluminum - conductor silver - c iron - c copper - c
record-breaking cold nights occur when the skies are
clear
In conduction, __ between particles transfer thermal energy
collisions
why can't energy move from the sun to Earth by conduction or convection?
conduction is the transfer of heat from molecule to molecule, and the convection is the transfer of heat by expansion and rising of matter. Both of these are impossible in space because there is almost no matter
what is a conductor
conductor is a material that conducts heat well
an object hotter than its surroundings eventually __ to match the surrounding temperature
cools
a good. absorber of radiant energy appears __
dark
in expanding air, the average speed of the molecules __ and the air cools
decreases
radiation is energy transmitted by
electromagnetic waves
define radiant energy
energy that is transmitted by radiation
all substances continuously emit only one specific wavelength of radiant energy. true or false?
false
as air rises, it expands because more atmospheric pressure squeezes on it at higher altitudes. true or false?
false
both heat and cold are forms of energy. true or false?
false
materials that are good conductors of heat are usually poor conductors of heat are usually poor conductors of electricity. true or false?
false
the average __ of radiant energy is directly proportional to the Kelvin temperature of the emitter
frequency
in convection, heat is transferred by movement of the __ substance from one place to another
hotter
the part of radiant energy that is absorbed by objects increases the __ energy of the objects
internal
you notice that a blacktop pavement becomes hotter than other nearby surfaces on a hot day. What will you notice about the temperature of the blacktop pavement at night
it will cool faster than other surfaces
order the star colors white, red, and blue from coolest to hottest
red, white, blue
explain why the inside of a car becomes so much hotter than its surroundings on a hot day
short wavelengths from the sun can pass through the car's glass and into the car, warming the car. The car radiates longer wavelengths that cannot pass out through the glass. The energy is trapped inside the car
explain why snow is sometimes used to construct dwellings in cold climates
snowflakes imprison a lot of air in their crystals and are good insulators. the snow prevents heat from escaping too rapidly
the radiant energy emitted by stars is called
stellar radiation
an infrared thermometer measures the infrared radiant energy emitted by a body and converts it to
temperature
the __ of an object doesn't change if it is in thermal equilibrium
temperature
the radiant energy emitted by Earth is called
terrestrial radiation
suppose a heater is placed near the floor of a room. Describe the steps in which convection currents keep the air stirred up in the room
the heater warms nearby air, and the warm air rises. Cooler air near the ceiling moves downward, and the heater warms it. This air then rises, and the process continues.
a figure shows ice at the bottom of a test tube and boiling water at the top. Explain why the heat that boils the water doesn't melt the ice
the hot water a the top of the tube is less dense and floats. Any heat that reaches the ice must be transferred by conduction, but water is a poor conductor of heat
state Newton's law of cooling
the rate of cooling of an object is approximately proportional to the temperature difference between the object and its surroundings
a hot apple pie will cool faster in a freezer than on a kitchen table because __
the temperature difference is greater
define conduction
the transfer of energy within materials and between different materials that are in direct contact
what is the greenhouse effect?
the warming of a planet's surface due to the trapping of radiation by the planet's atmosphere