Earth Science

19

Subject Area Standards Assessment Guide, Quarter 3 “Maps, Structure & Composition of the Atmosphere, Thermal Struct

ure, Composition and Ocean Circul

ation, Air Pressure and Winds”

Standards

What should be taught?

[According to the Science Frameworks]

KEY IDEAS/

VOCABULARY LIST

Sample Test Question

4a. Students know the relative amount of incoming solar energy compared with Earth’s internal energy and the energy used by society.

Most of the energy that reaches Earth’s surface comes from the

Sun as electromagnetic radiation

concentrated in infrared, visib

le,

and ultraviolet wavelengths. The energy avai

lable from the Sun’s radiation exceeds all

other sources of energy available at Ear

th’s

surface. There is energy within Earth, some of which is primitiv

e, or original, heat from the pl

anet’s formation and some that

is

generated by the continuing decay of radioactive elements. Over sh

ort periods of time, however, only a small amount of that ene

rgy

reaches Earth’s surface. The enormous amount of en

ergy remaining within Earth powers plate tectonics.

Human societies use energy for heating, lighti

ng, transportation, and many other modern

conveniences. Most of this energy came

to

Earth as solar energy. Some has been stored as fossil fu

els, plants that stored energy through photosynthesis.

Fossil fuels, including oil, natural gas, and

coal, provide the majority of energy used

by contemporary economies. This energy,

which has been stored in crustal rocks during hundreds of millions

of years, is ultimately limited. On average a U.S. household

consumes energy at the rate of about 1 kilowatt, or 1,000 joules

of energy, per second. The Sun delivers almost this much power

to every square meter of the illuminated side

of Earth. For this reason total energy u

se by humans is small relative to the tot

al

solar energy incident on Earth every day,

but harvesting this energy economically po

ses a challenge to modern engineering.

ELECTROMAGNETIC SPECTRUM INCOMING SOLAR RADIATION WAVELENGTHS OF LIGHT REFLECTION ABSORPTION ABSORPTION PHOTOSYNTHESIS INFRARED LIGHT [HEAT] ULTRAVIOLET LIGHT

4b. Students will describe and diagram the fate of incoming solar radiation in terms of reflection, absorption, and photosynthesis.

The fate of incoming solar radiation, whic

h is concentrated in the visible region of

the electromagnetic sp

ectrum, is determine

d by

its wavelength. Longer wavelength

radiation (e.g., infrared) is absorbed by

atmospheric gases. Shorter wavelengths of solar

electromagnetic energy, particularly in the visible range, are no

t absorbed by the atmosphere, except for the absorption of ult

raviolet

radiation by the ozone layer of the upper atmosphere. Some of th

e incident visible solar radiation is reflected back into space

by

clouds, dust, and Earth’s surface,

and the rest is absorbed.

Plants and other photosynthetic or

ganisms contain chloroph

yll that absorbs light in the oran

ge, short-red, blue, and ultraviole

t

portions of the solar radiation spectrum. The absorption of visi

ble light is less for green and yellow wavelengths, the reflect

ion of

which accounts for the color of leaves. The plant uses the absorbed

light energy for photosynthesi

s, in which carbon dioxide an

d

water are converted to sugar, a process that

is used to support plant growth and cell

metabolism. A by-product of photosynthesi

s is

oxygen. The amount of carbon dioxide in

the atmosphere declines slightly during th

e summer growing season and increases again

in the winter. The solar energy stor

ed in plants is the

primary energy source

for life on Earth.

VISIBLE REGION OF THE EM SPECTRUM INVISIBLE REGION ATMOSPHERIC GASES FATE OF INCOMING RADIATION WAVELENGTHS OF LIGHT USED FOR PHOTOSYNTHESIS CARBON DIOXIDE AND OXYGEN

Earth receives energy from the sun through what method of heat transfer? A

conduction

B

convection

C

radiation

D

none of the above

SOURCE: Old Test Bank DIFF: Level 1 NOTE: “None of the above” as an op

tion is highly discouraged and never

appears in CST questions.

4c. Students will describe the different atmospheric gases that absorb the Earth’s thermal radiation and explain the mechanism and significance of the greenhouse effect.

Every object emits electromagnetic radiation

that is characteristic of the temperature of the object. This phenomenon is called

“blackbody” radiation. For example, an iron bar heated in a fi

re glows red. At room temperat

ures the radiation emitted by the

bar is in the far infrared region of the

electromagnetic spectrum and cannot be seen

except with cameras with infrared imaging

capability. The Sun is much hotter than Earth; theref

ore, energy reaching Earth from the Sun ha

s, on average, much shorter wavelengths

than the infrared wavelengths that Earth em

its back into space. Energy reaching Eart

h is mostly in the visible range, and a

portion of this energy is absorbed. However, for the planet to

achieve energy balance, all the in

coming solar energy must be ei

ther

reflected or reradiated to space. Eart

h cools itself as the Sun does, by emit

ting blackbody radiation; but because

Earth is cooler than the Sun, Earth’s radiation peaks in

the infrared instead of in the visible wavelengths.

Certain gases, particularly

water vapor, carbon dioxide, methane, and some ni

trogen oxide pollutants, transmit visible light bu

t

absorb infrared light. These atmo

spheric constituents, therefore,

admit energy from the Sun but inhibit the loss of that energy

back

into space. This phenomenon is known as

the greenhouse effect, and these constituents

are called greenhouse gases. Without them

Earth would be a colder place in which to live. Human activity,

such as the burning of fossil fu

els, is increasing the concentr

ation

of greenhouse gases in the atmosphere. Th

is buildup can potentially cause a significa

nt increase in global temperatures and aff

ect

global and regional weather patterns. Pred

icting the precise long-term impact is diff

icult, however, because the influence of c

loud

cover and other factors is poorly understood.

“BLACK BODY” RADIATION GREENHOUSE GASES GREENHOUSE EFFECT WATER VAPOR METHANE NITROGEN OXIDE POLLUTANTS

Which of these could increase average global temperatures? A

increased use of fossil fuels

B

increased ocean algal blooms

C

decreased carbon dioxide emissions

D

increased numbers of animal species

SOURCE: Old Test Bank DIFF: Level 1

8a. Students will describe the thermal structure of the atmosphere and the chemical composition of the layers of the

atmosphere.

The atmosphere is a mixture of gases: nitrogen (78 percent), ox

ygen (21 percent), argon (1 perc

ent), and trace gases, such as

water vapor and carbon dioxide. Gravity pulls air toward Earth,

and the atmosphere gradually be

comes less dense as elevation

increases. The atmosphere is classified into

four layers according to the temperatur

e gradient. The temperature decreases with

altitude in the troposphere, the first laye

r; then similarly increases in the stratosp

here, the second layer; decreases in the

mesosphere,

the third layer; and increases in the thermo

sphere (ionosphere), the fourth layer.

The troposphere, the layer in which weather occurs, supports life

on Earth. The stratosphere is less dense than the troposphere

but

has a similar composition except

that this second layer is nearly devoid of wate

r. The other difference is that solar radiation

ionizes atoms in the stratosphere and dissociates oxygen to form

ozone, O3. This process is impo

rtant to life on Earth because

ozone absorbs harmful ultraviolet radiation that would otherwis

e cause health problems. Air in the mesosphere has very low

GASEOUS COMPOSITION OF THE ATMOSPHERE DENSITY VS. ELEVATION LAYERS OF THE ATMOSPHERE TROPOSPHERE MESOSPHERE IONOSPHERE STRATOSPHERE OZONE LAYER

The form of oxygen that combines thre

e oxygen atoms into each molecule is

called ____. A

argon

B

thermopause

C

chlorofluorocarbon

D

ozone

SOURCE: Old Test Bank DIFF: Level 1