N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
CHEMISTRY & HEAT
The Atom
Elements are the building blocks of matter. Elements are made up of atoms. It is
the smallest particle into which an element can be divided and still retain its
identity. An element is matter made up of atoms of only one kind. Students are
introduced to the structure and parts of an atom for the first time in 8th grade.
IPC TEK 7B requires students trace the historical development of the atomic
theory, but students may learn about this theory in 8th grade as a means to
introduce the atom. The names of scientists and dates of discovery may be used,
but they are not as important as the conceptual understanding of how we came to
know about atoms and their structure. This introduction would reinforce the idea
that elements are made up of atoms and compounds are composed of elements, a
concept that was first covered in 7th grade. Primary emphasis, however, should be
on the modern electron cloud theory of the atom, including the properties of mass
and electrical charge.
The Atomic Theory was postulated by John Dalton in the late 1700’s. He studied
elements until he began to understand that elements were made up of atoms. From
his studies he published the following points of the Atomic Theory:
1. all matter is made of atoms
2. atoms cannot be divided into smaller pieces
3. all the atoms of a particular element will be exactly alike
4. atoms can join with other atoms to create new substances
In 1897 J.J. Thomson figured out that although most of Dalton’s observations
were correct, the atom did have smaller parts. Using a cathode ray tube, Thomson
found negative particles, which he named “electrons”. Since Thompson knew that
the atom did not have a charge, he hypothesized that for every negative electron,
there would be a positive particle that would cancel out the charge. He did not,
however, know where these particles existed within the atom. In the early 1900’s
Ernest Rutherford decided to test Thompson’s atomic model theory. He directed a
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
1
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
beam of positively charged particles through a thin piece of gold. Most of the
particles from the radioactive element went straight through the gold sheet, but
some of the particles were deflected or bounced back. This would only occur if
there were positive particles in the center that were repelling the like-charged
particles from the beam. Rutherford came up with a new atomic model which
showed a dense nucleus containing positive particles (called protons) and tiny
electrons that were around the nucleus. Niels Bohr (1913) further studied the
model of the atom and his design showed a dense positive nucleus with electrons
orbiting around the nucleus in definite pathways. Twenty years after Rutherford
came up with his model of the atom, the nucleus was discovered. The nucleus holds
the majority of the mass of the atom, consisting of the neutrons (which have no
charge) and the protons (which have a positive charge.) Electrons are so small that
their mass does not significantly add to the mass of the atom.
Today the model of the atom is called the “electron cloud”. It describes a dense
nucleus made up of protons and neutrons with electrons which orbit the nucleus.
The electrons do not orbit in direct paths but within clouds or regions of space
where they are likely to be found. The movement of the electrons is similar to the
motion of fan blades in that they are moving so fast you cannot see them
individually.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
2
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
The following chart is a summary of critical information related to the structure
of the atom:
Name of particle
proton
electron
THE ATOM
Charge of particle
Where it is found
positive
in the nucleus
orbiting the nucleus
negative
Size/mass
1 atomic mass unit
almost zero
neutron
neutral
1 atomic mass unit
in the electron cloud
in the nucleus
The number of protons in an atom is called the atomic number.
The number of protons and neutrons in an atom is called the atomic mass.
The Periodic Table
Students were first introduced to the periodic table in 7th grade. At this level,
students described physical properties of elements and identified how they were
used to position an element on the periodic table. They recognized that numbers
increased from left to right and from top to bottom on the table. They classified
elements as metals, nonmetals or metalloids, studied the properties of these
categories, and examined the placement of elements within these categories on the
periodic table. Periods and groups were terms used to refer to the rows and
columns. The 7th grade student did not have an extensive lesson on the periodicity
of the table. Atomic number, atomic mass and the concept of valence electrons
were not introduced since 8th grade is the first time in which students are exposed
to the structure and parts of the atom. It is the 8th grade student that will
interpret information on the periodic table to understand that physical properties
are used to group elements.
The Periodic Table of the Elements that we use today was first created and
organized by a chemist named Dmitri Mendeleev in 1869. Mendeleev placed
elements with similar physical and chemical characteristics into columns.
Mendeleev arranged the elements according to their atomic mass (number of
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
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N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
protons and neutrons). He started with the element hydrogen. He even skipped
spaces where an element should be if it had not been discovered yet. Later, as
other elements were discovered, they were placed into the table. In the early
1900’s, a scientist name Moseley improved the design of the periodic table and
arranged the elements in order of increasing atomic number (number of protons.)
This is how the periodic table is arranged today. There have been approximately
115 elements discovered and placed into the modern periodic table. The first 92
elements can be found in nature. Elements 93 on are synthetic, created in a lab.
Many of the elements that are man-made are radioactive.
The periodic table is not meant to be memorized. The Aug. 2005 TAKS
information booklet states “the periodic table will be used as a tool to find
information such as element names, symbols, atomic mass, number of protons and
neutrons, and the physical and chemical properties of elements.” Based on this
statement, it is understood that students need to know the number of protons in
an atom of an element can be ascertained by looking at the atomic number. The
number of neutrons, however, must be calculated by subtracting the atomic number
from the atomic mass. An example is as follows: Lithium is the third element on
the periodic table. Its atomic number is 3, indicating it has 3 protons. The atomic
mass is 6.941 which can be rounded up to 7. The number of neutrons in an atom of
lithium would be 7 – 3 = 4.
Students should also understand that the table shows trends and is extremely
useful to the study of chemistry. It allows the chemist to have the ability to
predict how certain elements will react when joined together. It is recommended
that students practice using the table provided on the TAKS formula chart for
middle school science. Tables that group elements according to colors change with
each textbook and will not be utilized at all on the TAKS test. The TAKS periodic
table can be accessed on page 15 of the information booklet with the following link:
http://www.tea.state.tx.us/student.assessment/taks/booklets/science/g8e.pdf. A
copy of the table is also provided on the following page:
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
4
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
5
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
Each element on the table is represented by a symbol of one or two letters. Rules
for writing symbols are:
1) the first letter is always capitalized
2) if the symbol has two letters then the second letter is
lower case.
For example, S is the symbol for sulfur and Au is the symbol for gold.
Each square on the periodic table contains information specific to that element.
The following is the key from the table used on the TAKS formula chart,
illustrating how this information is provided for students to use and interpret:
Students need to understand how the periodic table is organized into periods and
groups. A row on the periodic table is called a period. Elements in the same row
have something in common -- the same number of energy levels (orbitals). Every
element in the top row, period 1, has one energy level for its electrons. All of the
elements in the second row, period 2, have electrons in two energy levels; period 3
elements have three energy levels, etc.
A column on the periodic table is called a group. Elements in the same group have
something in common -- the same number of electrons in their outer energy levels.
These outer electrons are called valence electrons. Elements in Group 1 have one
valence electron, and elements in Group 2 have two valence electrons. Groups 3
through 12 (transition metals) have a varying number of valence electrons. For
Groups 13 through 18, the number of valence electrons is equal to the group
number minus 10. The exception to this rule is helium. Helium is in Group 18.
Helium atoms have only two electrons, so they have two valence electrons rather
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
6
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
than eight. The following chart shows the pattern of valence electrons for each
group:
Elements that are classified as metals are found on the left side of the periodic
table. The most reactive metals are found in group 1 . This has to do with the
valence electrons. The valence electrons can be gained, shared or lost, forming
bonds with other atoms. Elements in group 1 are very reactive because they have a
tendency to give away their valence electron to an element found on the right side
of the periodic table. Elements on the right side are classified as nonmetals. The
elements in group 17 are very reactive nonmetals. They need just one more valence
electron to fill their outer energy level. The periodic table also contains a dark
zigzag (stair-step) line. Elements on either side of this line are called metalloids.
Metalloids have some properties of metals and some properties of nonmetals.
Students studied the properties of metals, nonmetals and metalloids in 7th grade,
but it would be appropriate to review those concepts during this course of study.
The chart below reviews the properties of metals, nonmetals and metalloids. The
elements that are in the last column are called the noble gases. These elements
have enough electrons to fill their outer energy level so they do not react with
other elements in nature.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
7
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
Chemical Reactions
The 8th grade student knows that substances have chemical and physical
properties. In elementary grades, students were introduced to chemistry through
the study of matter and its properties, including state, size, color, mass, hardness,
density, and buoyancy. In 5th grade students classified matter based on its
physical properties, including magnetism, physical state, and the ability to conduct
or insulate heat, electricity, and sound. They also studied mixtures and learned
about solutions as a type of mixture. Students were introduced to chemical
properties in 6th grade and were asked to classify substances by their physical and
chemical properties. They were also introduced to the concept that when a
chemical reaction occurs, the new substance formed has its own set of properties.
7th grade focused on identifying everyday examples of chemical phenomena, such as
rusting, tarnishing and burning. They also recognized that compounds formed in
chemical reactions were composed of elements. In 8th grade the extension is that
students are to demonstrate that substances may react chemically to form new
substances. In addition, students in 8th grade are first introduced to the concept
that these reactions can be represented with the use of chemical formulas and
equations.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
8
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
Substances react to chemically form new substances known as compounds. Clues
that can help determine if a chemical change has occurred are production of vapor,
light, gas bubbles, a precipitate, odors, and sometimes a color change. The release
or absorption of heat may also indicate a chemical change has occurred. A process
that produces a chemical change is called a chemical reaction. The substances that
one starts out with are known as reactants. The substances that one ends up with
are known as the products.
Chemical reactions involve changing the arrangements of the atoms. Bonds
between the atoms are broken and new bonds are formed. The 2005 TAKS
information booklet states “students should understand the basic concept of
conservation of mass (mass is neither lost nor destroyed in a regular chemical
reaction).” As a result, the 8th grade student will need to recognize the
importance of formulas and equations to express what happens in a chemical
reaction. Using formulas for compounds is how scientists describe the chemical
compounds found in a reaction. Formulas are made of the atoms that compose the
compound and the correct ratio is given using subscript numbers. The formula for
water is H20. This means that the formula for water has two atoms of hydrogen
and one atom of oxygen.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
9
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
The 2005 TAKS information booklet states “students should be able to recognize
the elements that make up common compounds, such as water, sugar, and salt.”
The following table lists the formulas students should know at this level:
EXAMPLES OF SOME COMMON CHEMICAL FORMULAS
Name
Formula
water
H 20
oxygen
02
sodium chloride (table salt)
NaCl
glucose (simple sugar made by plants)
C6H12O6
carbon dioxide
C02
Students should also understand that each
of the above examples can be referred to as
a molecule. Molecules are simply substances
with two or more atoms.
Chemical equations are used to express what actually happens during the chemical
reaction. The equation is read from left to right. The reactants are written on
the left side of the arrow. The products are written on the right side of the
arrow. The arrow indicates the direction that the reaction is taking place.
For example:
In photosynthesis: water + carbon dioxide
glucose + oxygen
Read aloud this reaction would say: water plus carbon dioxide produces (or yields)
glucose and oxygen.
Using formulas the reaction would look like this:
H20 + C02
C6H1206 + 02
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
10
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
According to the above equation, 2 hydrogen atoms, 3 oxygen atoms and 1 carbon
atoms produces 6 carbon atoms, 12 hydrogen atoms and 8 oxygen atoms. This does
not support the law of conservation of mass that says matter can be neither
created nor destroyed. The number of atoms on the left side of the equation
should equal the number of atoms on the right side of the equation. To balance the
equation, place a large number in front of the formula to increase all the atoms in
that particular formula. The large numbers used in front of a formula is called a
coefficient. You multiply the coefficient by the subscript to obtain the number of
atoms. If there is no subscript then you multiply the coefficient by one.
A balanced equation for photosynthesis would look like this:
6C02 + 6H20
C6H12O6 + 602
Now there are 6 carbon atoms, 18 oxygen atoms and 12 hydrogen atoms on the
both sides of this equation, indicating it is balanced. When looking at the above
equation, students should also recognize there are 6 molecules of carbon dioxide, 6
molecules of water, 1 molecule of glucose and 6 molecules of oxygen. According to
the 2005 TAKS information booklet, students should “focus on identifying
rearrangement of atoms” because at this level, they are “not required to balance
chemical equations.”
The 2006 TAKS Study Guide takes students through the progression of the above
concepts using another equation, the formation of tarnish. It also contains sample
questions utilizing the equations for the formation of rust and cellular respiration
(reciprocal of photosynthesis). Equations of reactions such as these are practical
to use since they directly relate to other concepts to which students have been
exposed. The reaction for the formation of tarnish (silver sulfide) is as follows:
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
11
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
The reaction for the formation of rust (iron oxide) is as follows:
It should be understood that students do not need to memorize the above
equations, but be able to interpret them, break them down into their parts
(numbers of atoms, molecules, etc.), and explain what is occuring.
Everyday Materials
The science of chemistry is an amazing field of study. Some chemists study the
physical and chemical properties of materials in order learn how to combine them
and make new ones. Chemists are also responsible for many of the practical
applications once a new material or product has been formed. New compounds have
improved lives, and many we take for granted. The table below lists examples of
materials we use everyday and their uses. It is not intended to be a comprehensive
list or one that should be memorized by students. It is provided as a reference
tool.
Name
SYNTHETIC MATERIALS & THEIR USES
How it is made
Used For:
stainless steel
iron + chromium + heat
brass
copper + zinc + heat
pewter
bronze
lead + tin + heat
copper + tin + heat
steel
iron, limestone (calcium
carbonate), coal(carbon) +
pans, sinks, tableware, scissors,
conducts heat
musical instruments such as
trumpets, French horns, tubas,
light fixtures, statues, etc;
conducts heat
bowls, figurines, conducts heat
tools, statues, gunmetal, awards;
conducts heat
buildings, tools, ships, bridges,
magnets, file cabinets, etc;
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
12
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Name
glass
Unit 1
Chemistry & Heat
Spring 2006
SYNTHETIC MATERIALS & THEIR USES
How it is made
Used For:
tremendous heat
silicon, soda ash, limestone +
heat
paper
plant fibers, special machines,
chemicals
Plastics: nylon
chemicals found in crude oil
plus additives
Plastics: polyethylene
chemicals found in crude oil
plus additives
Plastics: polystyrene
(Styrofoam)
chemicals found in crude oil
plus additive
Plastics: bakelite
chemicals found in crude oil
plus additives
Plastics: vinyl
(polyvinyl chloride
chemicals found in crude oil
plus additives
conducts heat
bottles, all kinds of containers,
windows, dishes, decorative
objects, light bulbs, eyeglasses;
good insulator
paper towels, writing tablets,
Kleenex, boxes, books, cartons,
newspapers & magazines, etc
ropes, women’s stockings,
parachutes, bristles on a
toothbrush; insulator
milk jugs, peanut butter jars,
squeeze bottles, toys, trash bags,
etc; good insulator
cups, plates, containers of all
kinds, packing supplies; good
insulator
cooking pots, toilet seats, knife
handles, billiard balls; good
insulator
shower curtains, steering wheels;
good insulator
Production of new materials created through chemical reactions are used daily.
Sometimes the products are discovered accidentally. Spandex, Velcro strips,
Kevlar (used to make bulletproof vests), fleece (used in place of wool), artificial
turf on a football field, sun resistant clothing are just a few of the newer products
made synthetically by the chemical industry. Many failed experiments go into
finding the right combination to create new materials that have a useful purpose.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
13
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
Heat
Heat energy surrounds all living things on earth. The Sun gives the planet heat for
plants to photosynthesize. Food, when digested, gives the body the heat (or
energy) it needs to keep the process of living ongoing. Heat is the transfer of
energy between objects of different temperatures. The transfer of heat energy
is also known as thermal energy. All matter is composed of atoms and molecules
that are moving. Molecules move faster when the temperature increases. The
movement of molecules is known as kinetic energy. Heat is always transferred
from the hotter object to the cooler one.
There are three types of heat transfer: conduction, convection and radiation.
Conduction is the transfer of heat through direct contact. A hot sidewalk will
warm bare feet through conduction. Convection is the transfer of heat in a fluid
through currents. Wind or air masses illustrate this type of heat transfer. Warm
or cool ocean currents are another example of convection. Radiation is the
transfer of energy or heat as electromagnetic waves. Radiation can occur in outer
space where there are no moving molecules. This is the form of energy that brings
the heat of the sun to earth.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
14
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
Specific heat is the amount of energy needed to change the temperature of l gram
of a substance by 1o C in temperature. Specific heat is a physical property of a
substance just like size, and state of matter. Different substances have different
specific heat capacities. In other words, some substances get hot very quickly
when exposed to heat while other substances do not rise in temperature very
quickly when exposed to the same amount of heat.
A higher a substance’s specific heat, the harder it is to increase its temperature.
As a result, specific heat can be viewed as the resistance of a substance to change
in temperature. In other words, a higher specific heat means that more energy is
required to change that substance’s temperature.
Students should also relate the property of specific heat to conductivity. Most
metals, which are good conductors, have a low specific heat. Most nonmetal
compounds, which are poor conductors, have a high specific heat. The following
table lists some examples, illustrating this relationship:
The high specific heat of water
should be noted. This
characteristic is important because
it helps to maintain the equilibrium
of Earth’s climate as so much of
our planet is covered in water.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
15
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
According to the 2005 TAKS information booklet, the 8th grade student does not
need to know how to calculate specific heat mathematically. “Students should
recognize specific heat as a property of a substance and have a general
understanding of how it affects the world around us (including) applications of
specific heat, such as why oceans hold heat better than large landmasses.”
Loss or gain of heat energy occurs during exothermic and endothermic chemical
reactions. Chemical energy is a part of all reactions. During a chemical reaction
bonds are either broken or made. When a bond is made chemical energy (usually in
the form of heat) is absorbed. The reaction will actually result in a decrease in
the temperature of the resulting product in comparison to the temperature of the
reactants. This type of reaction is called an endothermic reaction. On the other
hand, when chemical bonds are broken, energy is released (usually in the form of
heat or light). After it occurs, this reaction either gives off light or produces
heat and the temperature rises after the reactants have chemically combined.
This type of reaction is called an exothermic reaction. The Law of Conservation of
Energy states that energy can neither be created nor destroyed. An example
would be the amount of energy given off during an exothermic reaction would equal
the amount of energy that was being held in the bonds of the reactants. In some
chemical equations, the word “energy” is used in a way to let the scientist know
that heat is either given off or absorbed.
For example:
CH4 + 202
C02 + 2H20 + energy
This equation would read: methane gas plus oxygen yields carbon dioxide and water
and energy. This is an exothermic reaction because energy is being produced.
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
16
N o r t h E a st I n d ep en d e nt S c h o o l D i st ric t
8th Grade Science
Unit 1
Chemistry & Heat
Spring 2006
Clarifying statements are intended to deepen teachers’ understanding of science concepts and serve as a guide for
instructional design. They are not intended to serve as student instructional materials.
This publication is the property of North East Independent School District. Duplication in whole or in part, outside of NEISD, is
prohibited without express written permission from NEISD.
17