CHAPTER 4: THE PHYSICAL SETTING
A. THE UNIVERSE
K-2
There are more stars in the sky than anyone can easily
count, but they...
The sun can be seen only in the daytime, but the
moon can be seen sometimes...
The moon looks a little different every day, but
looks the same again...
3-5
The patterns of stars in the sky stay the same, although
they appear to move...
Telescopes magnify the appearance of some distant
objects in the sky...
Planets change their positions against the background
of stars.
The earth is one of several planets that orbit the
sun, and the moon orbits...
Stars are like the sun, some being smaller and some
larger, but so far away...
6-8
The sun is a medium-sized star located near the edge
of a disk-shaped...
The sun is many thousands of times closer to the
earth than any other star...
Nine planets of very different size, composition,
and surface...
Large numbers of chunks of rock orbit the sun. Some
of those that the earth...
9-12
The stars differ from each other in size, temperature,
and age...
On the basis of scientific evidence, the universe
is estimated to be...
Increasingly sophisticated technology is used to
learn about the universe...
Mathematical models and computer simulations are
used in studying...
B. THE EARTH
K-2
Some events in nature have a repeating pattern. The
weather changes...
Water can be a liquid or a solid and can go back
and forth from one form...
Water left in an open container disappears, but water
in a closed container...
3-5
Things on or near the earth are pulled toward it
by the earth's gravity.
Like all planets and stars, the earth is approximately
spherical in shape...
When liquid water disappears, it turns into a gas
(vapor) in the air...
Air is a substance that surrounds us, takes up space,
and whose movement...
6-8
We live on a relatively small planet, the third from
the sun in the only system...
The earth is mostly rock. Three-fourths of its surface
is covered by...
Everything on or anywhere near the earth is pulled
toward the earth's...
Because the earth turns daily on an axis that is
tilted relative to the plane...
The moon's orbit around the earth once in about 28
days changes...
Climates have sometimes changed abruptly in the past
as a result of changes...
The cycling of water in and out of the atmosphere
plays...
Fresh water, limited in supply, is essential for
life and also for most industrial...
Heat energy carried by ocean currents has a strong
influence on climate...
Some minerals are very rare and some exist in great
quantities...
The benefits of the earth's resources--such as fresh
water, air, soil...
9-12
Life is adapted to conditions on the earth, including
the force of gravity...
Weather (in the short run) and climate (in the long
run) involve the transfer...
C. PROCESSES THAT SHAPE THE EARTH
K-2
Chunks of rocks come in many sizes and shapes, from
boulders to grains...
Change is something that happens to many things.
Animals and plants sometimes cause changes in their
surroundings.
3-5
Waves, wind, water, and ice shape and reshape the
earth's land...
Rock is composed of different combinations of minerals.
Smaller rocks...
6-8
The interior of the earth is hot. Heat flow and movement
of material within...
Some changes in the earth's surface are abrupt (such
as earthquakes...
Sediments of sand and smaller particles (sometimes
containing...
Sedimentary rock buried deep enough may be reformed
by pressure...
Thousands of layers of sedimentary rock confirm the
long history...
Although weathered rock is the basic component of
soil, the composition...
Human activities, such as reducing the amount of
forest cover...
9- 12
Plants alter the earth's atmosphere by removing carbon
dioxide...
The formation, weathering, sedimentation, and reformation
of rock...
The slow movement of material within the earth results
from heat...
The solid crust of the earth--including both the
continents and the ocean...
Earthquakes often occur along the boundaries between
colliding plates...
D. STRUCTURE OF MATTER
K-2
Objects can be described in terms of the materials
they are made of...
Things can be done to materials to change some of
their properties...
3-5
Heating and cooling cause changes in the properties
of materials...
No matter how parts of an object are assembled, the
weight...
Materials may be composed of parts that are too small
to be seen without...
When a new material is made by combining two or more
materials...
6-8
All matter is made up of atoms, which are far too
small to see directly...
Equal volumes of different substances usually have
different weights.
Atoms and molecules are perpetually in motion. Increased
temperature...
The temperature and acidity of a solution influence
reaction rates...
Scientific ideas about elements were borrowed from
some Greek...
There are groups of elements that have similar properties,
including...
No matter how substances within a closed system interact
with one...
9-12
Atoms are made of a positive nucleus surrounded by
negative electrons...
The nucleus, a tiny fraction of the volume of an
atom, is composed of protons...
Neutrons have a mass that is nearly identical to
that of protons, but neutrons...
The nucleus of radioactive isotopes is unstable and
spontaneously decays...
Scientists continue to investigate atoms and have
discovered even smaller...
When elements are listed in order by the masses of
their atoms...
Atoms often join with one another in various combinations
in distinct...
The configuration of atoms in a molecule determines
the molecule's...
The rate of reactions among atoms and molecules depends
on how...
E. ENERGY TRANSFORMATIONS
K-2
The sun warms the land, air, and water.
3-5
Things that give off light often also give off heat.
Heat is produced...
When warmer things are put with cooler ones, the
warm ones lose...
Some materials conduct heat much better than others.
Poor conductors...
6-8
Energy cannot be created or destroyed, but only changed
from one form...
Most of what goes on in the universe--from exploding
stars and biological...
Heat can be transferred through materials by the
collisions of atoms...
Energy appears in different forms. Heat energy is
in the disorderly...
9-12
Whenever the amount of energy in one place or form
diminishes, the amount...
Heat energy in a material consists of the disordered
motions of its atoms...
Transformations of energy usually produce some energy
in the form of heat...
Different energy levels are associated with different
configurations of atoms...
When energy of an isolated atom or molecule changes,
it does so in a definite...
Energy is released whenever the nuclei of very heavy
atoms, such as uranium...
F. MOTION
K-2
Things move in many different ways, such as straight,
zigzag...
The way to change how something is moving is to give
it a push or a pull.
Things that make sound vibrate.
3-5
Changes in speed or direction of motion are caused
by forces...
How fast things move differs greatly. Some things
are so slow...
6-8
Light from the sun is made up of a mixture of many
different colors of light...
Something can be "seen" when light waves emitted
or reflected by it...
An unbalanced force acting on an object changes its
speed or path...
Vibrations in materials set up wavelike disturbances
that spread away...
Human eyes respond to only a narrow range of wavelengths
of electromagnetic...
9-12
The change in motion of an object is proportional
to the applied force...
All motion is relative to whatever frame of reference
is chosen...
Accelerating electric charges produce electromagnetic
waves around...
Whenever one thing exerts a force on another, an
equal amount...
The observed wavelength of a wave depends upon the
relative motion...
Waves can superpose on one another, bend around corners,
reflect off surfaces...
G. FORCES OF NATURE
K-2
Things near the earth fall to the ground unless something
holds them up.
Magnets can be used to make some things move without
being touched.
3-5
The earth's gravity pulls any object toward it without
touching it.
Without touching them, a magnet pulls on all things
made of iron and either...
Without touching them, material that has been electrically
charged pulls...
6-8
Every object exerts gravitational force on every
other object. The force...
The sun's gravitational pull holds the earth and
other planets...
Electric currents and magnets can exert a force on
each other.
9-12
Gravitational force is an attraction between masses.
The strength of...
Electromagnetic forces acting within and between
atoms are vastly...
There are two kinds of charges--positive and negative.
Like charges repel...
Different kinds of materials respond differently
to electric forces...
Magnetic forces are very closely related to electric
forces and can...
The forces that hold the nucleus of an atom together
are much stronger...
