CHAPTER 2
SCIENCE, MATTER, ENERGY AND SYSTEMS
Outline
2-1 What do scientists do?
A. Science is a search for order in nature.
2. Scientists use this knowledge to make predictions about future events in nature…
B. Scientists use observations, experiments, and models to answer questions about how nature works.
1. The scientific process uses these steps:
a. Identify a problem.
b. Find out what is known about the problem.
2. Important features of the scientific process are skepticism, reproducibility, and peer review.
C. Critical thinking and creativity are important in science
1. Critical thinking involves four important steps.
a. Be skeptical about everything you read or hear.
2. Imagination, creativity and intuition are also important tools in science.
D. Scientific theories and laws are the most important and certain results of science.
2. A scientific theory has been tested widely, is supported by extensive evidence, and is accepted
3. A scientific law is a well-tested and widely accepted description of events or actions of nature
that we find happening repeatedly in the same way.
4. Scientific laws cannot be broken except by discovering new data that lead to changes in the
law.
E. The results of science can be tentative, reliable, or unreliable.
1. Results that have not been widely tested or are not widely accepted can be called tentative or
frontier science. At this stage, disagreement among scientists is common and leads to
advancement.
3. Unreliable science includes results that have not been rigorously peer reviewed or that have
been discarded as a result of peer review.
4. Questions to ask to determine if scientific findings are reliable or unreliable include:
a. Was the experiment well designed? Did it involve a control group
b. Have other scientists reproduced the results?
Instructor’s Manual for Environmental Science, 15th edition
e. Are the investigators unbiased in their interpretations of the results? Were all the
investigators’ funding sources unbiased?
f. Have the data and conclusions been subjected to peer review?
g. Are the conclusions of the research widely accepted by other experts in this field?
h. If “yes” is the answer to each of these questions, then the results can be called reliable
science. Otherwise, the results may represent tentative science that needs further testing
and evaluation, or you can classify them as unreliable science.
F. Science has some limitations.
1. Scientists cannot prove or disprove anything absolutely because of inherent uncertainty in
3. Because the natural world is so complex, there are many variables that cannot be tested one at
2-2 What is matter and what happens when it undergoes change?
A. Matter consists of elements and compounds.
1. Matter is anything that has mass and takes up space, living or not.
3. Matter exists in two chemical forms, elements and compounds.
5. Elements are represented by a one- or two-letter symbol.
6. Compounds are combinations of two or more different elements bound in fixed proportions.
B. Atoms, ions, and molecules are the building blocks of matter.
1. An atom is the smallest unit of matter that exhibits the characteristics of an element.
a. Each atom consists of subatomic particles: positively charged protons, uncharged neutrons,
and negatively charged electrons.
2. A molecule is a combination of two or more atoms of the same or different elements held together
by chemical bonds
3. An ion is an atom or group of atoms with one or more net positive or negative charges.
4. pH is a measure of acidity based on the amount of hydrogen ions (H+) and hydroxide ions (OH–) in
5. Chemical formulas are a type of shorthand to show the type and number of atoms/ions in a
compound or molecule.
a. Each element in the compound is represented by a symbol (e.g., H = hydrogen, O = oxygen).
b. Subscripts show the number of atoms/ions in the compound (e.g. H2O, or water, has two
hydrogen atom and one oxygen atom). No subscript is used if there if only one atom of an
element.
C. Organic compounds are the chemicals of life.
1. Organic compounds contain at least two carbon atoms combined with various other atoms.
2. All other compounds are called inorganic compounds.
3. Types of organic compounds include:
Chapter 2: Science, Matter, and Energy
4. Macromolecules are large organic molecules. Many are polymers, large molecules made of
smaller subunits called monomers joined together.
5. The major types of organic molecules are:
a. Complex carbohydrates: two or more monomers of simple sugars such as glucose
b. Proteins: formed by monomers called amino acids
c. Nucleic acids: (DNA and RNA) formed by monomers called nucleotides
d. Lipids, which include fats and waxes, and are not always made of monomers.
D. Matter comes to life through genes, chromosomes, and cells.
2. Cells are the smallest and most fundamental structural and functional units of life.
4. Thousands of genes make up chromosomes, which are composed of DNA and proteins.
E. Some forms of matter are more useful than others.
2. Low-quality matter is not highly concentrated, is often located deep underground or dispersed in
the ocean or atmosphere, and usually has little potential for use as a resource.
F. Matter undergoes physical, chemical, and nuclear changes.
1. Physical change is not chemical composition change but a change in states, such as ice melting or
water freezing.
2. Chemical change or chemical reaction is a change in the chemical composition.
G. We cannot create or destroy atoms: the Law of Conservation of Matter.
1. Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed.
2-3 What is energy and what happens when it undergoes change?
A. Energy comes in many forms.
2. Kinetic energy is energy associated with motion.
a. Wind and flowing water are examples of kinetic energy.
3. Potential energy is stored energy.
a. Examples include water stored behind a dam and the chemical bonds in gasoline.
4. Potential energy can be changed to kinetic energy.
a. Examples include releasing water from behind a dam and burning gasoline in a car
5. Solar energy is major source of renewable energy.
6. Non-renewable fossil fuels provide the other 1% of the energy we use.
B. Some types of energy are more useful than others.
1. High-quality energy is concentrated and has a high capacity to do useful work.
2. Low-quality energy is dispersed and has little capacity to do useful work.
C. Energy changes are governed by two scientific laws.
1. The first law of thermodynamics, or the law of conservation of energy, states that when energy is
2. The second law of thermodynamics states that when energy is changed from one form to another,
energy quality is depleted.
2-4 What are systems and how do they respond to change?
2-1 What do scientists do?
CONCEPT 2-1
Scientists collect data and develop hypotheses, theories, and laws about how nature works.
2. State the importance of curiosity, skepticism, peer review, critical thinking and creativity in the
scientific process.
4. Describe the differences among frontier science, reliable science and unreliable science.
2-2 What is matter and what happens when it undergoes change?
CONCEPT 2-2A Matter consists of elements and compounds, which in turn are made up of atoms, ions, or
molecules.
CONCEPT 2-2B Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed
(the law of conservation of matter).
2. Define matter, elements, compounds and molecules. Describe the atomic theory and the sub-atomic
particles and structure of an atom.
4. Distinguish between organic and inorganic compounds.
6. Distinguish among physical, chemical, and nuclear changes.
2-3 What is energy and what happens when it undergoes change?
CONCEPT 2-3A Whenever energy is converted from one form to another in a physical or chemical change, no
energy is created or destroyed (first law of thermodynamics).
CONCEPT 2-3B Whenever energy is converted from one form to another in a physical or chemical change, we
end up with lower-quality or less-usable energy than we started with (second law of thermodynamics).
1. Define energy. Distinguish among forms of energy and between high- and low-quality energy.
3. Describe the implications of the laws of matter and energy for a long-term sustainable-Earth society.
2-4 What are systems and how do they respond to change?
CONCEPT 2.4 Systems have inputs, flows, and outputs of matter and energy, and feedback can affect their
behavior.
Key Terms
acidity
atoms
atomic number
chromosome
compound
corrective feedback loop
energy
energy quality
feedback
Chapter 2: Science, Matter, and Energy
gene
heat
high-quality energy
ions
inputs
isotopes
molecules
natural radioactive decay
negative feedback loop
neutrons
nuclear change
nuclear fission
principles of sustainability
protons
reliable science
science
scientific hypothesis
scientific law
Teaching Tips
Ask the students to describe what scientists “do,” or how scientists expand our knowledge base. Lead the
discussion to controlled experiments, namely how scientists develop experiments and test hypotheses. Use
the discussion of controlled experiments to introduce the core case study, Hubbard Brook.
• Use the core study to solidify the students’ understanding of control group, experimental group,
and baseline data. Here, Borman and Likens perform the daunting task of conducting a controlled
experiment in the field. Therefore, laboratory and field experiments can be compared.
• Many students have little notion of how science is “done.” Considerable time should be spent
discussing what science is, including the scientific method, its uses, and limitations.
• As the underpinning of all topics discussed in the course/book, the topics of matter, energy, and
energy use should be emphasized.
Ask the students to select a scientist (you can have index cards with scientists (name, dates, location,
Instructor’s Manual for Environmental Science, 15th edition
Discussion Topics
1. According to the law of the conservation of matter, whenever energy is converted from one form to
another in a physical or chemical change, no energy is created or destroyed. Therefore, can we get
something for nothing? Explore the attempts of advertising to convince the public that we can indeed
2. How much are you willing to pay in the short term to receive long-term economic and environmental
benefits? Explore costs and payback times of energy-efficient appliances, energy-saving light bulbs,
3. What actions can you take to improve your home’s energy efficiency and reduce consumption of
materials? Do you believe these reductions will increase or decrease your quality of life?
4. What is our national energy policy? How has it changed over the past 20 years? Is our current policy
supported by the science in this chapter regarding the laws of energy? What are the short- and long-
term economic, environmental, and national-security implications?
5. What would it be like to lead a low-energy lifestyle? Are people already successfully using less energy
while maintaining a high quality of life? What are some of the challenges in convincing more people to
embrace a low-energy lifestyle?
Activities and Projects
1. A human body at rest yields heat at about the same rate as a 100-watt incandescent light bulb. As a
class exercise, calculate the heat production of the student body of your school, the U.S. population,
and the global population. Where does the heat come from? Where does it go?
2. As a class exercise, conduct a survey of the students at your school to determine their degree of
3. Ask a physics or chemistry instructor to visit your class and, by using simple experiments, demonstrate
the matter and energy laws.
4. As a class exercise, make an inventory the types of appliances that are used to maintain a classroom
5. Invite a medical technician to speak to your class on the beneficial uses of ionizing radiation. Discuss
the controls that are employed to limit the risks associated with the use of radioisotopes for diagnostic
and treatment procedures?
Attitudes and Values Assessment
1. Where do you fit into the flow of energy from the sun?
2. Do you feel you play a role in nature’s cycles of matter and energy?
3. What is your body temperature? How does your body stay at that temperature even in the cold
weather? How do you feel when you are in air-conditioned or heated rooms?
© 2016 Cengage Learning
4. Do you use a lot of energy (e.g., lights, television, CD player, car, or heated water)? Where does the
energy come from? What could cause you to increase or decrease your usage?
5. How do you feel on a sunny day? A cloudy day? What is the wind doing with the atmospheric energy
on those days?
Laboratory Skills
Wells, Edward. Lab Manual for Environmental Science. 2009. Lab #1: Introduction to Experimental
Design.
News Videos
Finding alternatives to oil, The Brooks/Cole Environmental Science Video Library 2009, ©2011,
DVD ISBN-13: 978-0-538-73355-7
Additional Videos
The Scientific Method Song
A musical explanation of the scientific method
Digital Integration
Correlation to Global Environment Watch
Acid Rain Green Chemistry
Energy Efficiency
Instructor’s Manual for Environmental Science, 15th edition
Correlation to Explore More
Ecology Environmental Science
Energy Nature of Science
Environmental History Science
Suggested Answers to End of Chapter Questions
Answers will vary but these represent phrases from this chapter. The following are examples of the material
that should be contained in possible student answers to the end of chapter questions. They represent only a
Review
Core Case Study
1. Describe the controlled scientific experiment carried out in the Hubbard Brook Experimental Forest.
See page 26.
Section 2-1
2. What is the key concept for this section? What is science? List the steps involved in a scientific
process. What is data? What is a model? Distinguish among a scientific hypothesis, a scientific theory,
and a scientific law (law of nature). Summarize Jane Goodall’s scientific and educational
achievements. What is peer review and why is it important?
• The key concept for this section is that scientists collect data and develop theories, models, and
laws about how nature works.
• Science is an attempt to discover how nature works and to use that knowledge to make predictions
about what is likely to happen in nature.
• The steps of the scientific method are organized steps of problem-solving: making an initial
observation, asking questions about that observation, forming a specific and singular hypothesis,
testing that hypothesis, and then either reaching a conclusion, or revising the hypothesis to test
again.
• Data is the information needed to answer scientific questions usually obtained by making
observations and measurements.
Chapter 2: Science, Matter, and Energy
analyze the work to see if the data can be reproduced and whether the proposed hypothesis is
reasonable and useful.
3. Explain why scientific theories and laws are the most important results of science and most certain
results of science and why people often use the term theory incorrectly.
• Since the goal of science is to come up with theories and laws based on facts to explain how the
4. Distinguish among reliable science, unreliable science, and tentative science. What are four limitations
of science?
• Tentative science means preliminary scientific results that have not been widely tested and
accepted by peer review or tested and reproduced by other scientists are not yet considered to be
reliable.
• Environmental science and science in general have four important limitations:
o Scientists cannot prove or disprove anything absolutely, because there is always some degree
of uncertainty in scientific measurements, observations, and models.
o Scientists are human and thus are not totally free of bias about their own results and
hypotheses.
Section 2-2
5. What are the two key concepts for this section? What is matter? Distinguish between an element and a
compound and give an example of each. What is the periodic table of elements? Define atoms,
molecules, and ions and give an example of each. What is the atomic theory? Distinguish among
protons, neutrons, and electrons. What is the nucleus of an atom? Distinguish between the atomic
number and the mass number of an element. What is an isotope? What is acidity? What is pH?
• The key concepts for this section are:
Instructor’s Manual for Environmental Science, 15th edition
o Matter consists of elements and compounds, which in turn are made up of atoms, ions, or
molecules.
• Matter is anything that has mass and takes up space. It can exist in three physical states—solid,
liquid, and gas, and two chemical forms—elements and compounds.
• An element is a fundamental substance that has a unique set of properties and cannot be broken
down into simpler substances by chemical means. Compounds are a combinations of two or more
different elements held together in fixed proportions. An example of an element is oxygen. An
example of a compound is water (H2O), which contains two atoms of hydrogen and two atoms of
oxygen held together by bonds.
• The periodic table is a tabular arrangement of the chemical elements, organized on the basis of
their atomic numbers (numbers of protons in the nucleus), electron configurations, and recurring
chemical properties.
6. Define and give two examples of an organic compound. What are three types of organic polymers that
are important to life? What is a cell? Define gene, trait, and chromosome.
See pages 32–33. Student answers will vary slightly.
• An organic compound contains at least two carbon atoms combined with atoms of one or more
other elements.
Chapter 2: Science, Matter, and Energy
• Within some DNA molecules are certain sequences of nucleotides called genes. Each of these
distinct pieces of DNA contains instructions, or codes, called genetic information, for making
7. Distinguish between a physical change and a chemical change (chemical reaction) and give an example
of each. What is a nuclear change? Define and explain the differences among natural radioactive
decay, nuclear fission, and nuclear fusion. What is the law of conservation of matter?
See pages 33–34. Student answers will vary slightly.
• When a sample of matter undergoes a physical change, there is no change in its chemical
composition. A piece of aluminum foil cut into small pieces is still aluminum foil.
• When a chemical change, or chemical reaction, takes place there is a change in chemical
composition of the substances involved. Chemists use a chemical equation to show what happens
in a chemical reaction. For example, when coal burns completely, the solid carbon (C) in the coal
Section 2-3
8. What are the two key concepts for this section? What is energy? Define and distinguish between
kinetic energy and potential energy and give an example of each. What is heat (thermal energy)?
Define and give two examples of electromagnetic radiation. What is energy quality? Distinguish
between high-quality energy and low-quality energy and give an example of each. What is the first law
of thermodynamics (law of conservation of energy) and why is it important? What is the second law of
thermodynamics and why is it important? Explain why the second law means that we can never recycle
or reuse high-quality energy.
See pages 35–36. Student answers will vary slightly.
• The key concepts for this section are:
o Whenever energy is converted from one form to another in a physical or chemical
change, no energy is created or destroyed (first law of thermodynamics).
Instructor’s Manual for Environmental Science, 15th edition
• Heat is a form of kinetic energy, the total kinetic energy of all moving atoms, ions, or molecules
within a given substance. When two objects at different temperatures contact one another, heat
flows from the warmer object to the cooler object.
• Electromagnetic radiation is energy that travels in the form of a wave as a result of changes in
electrical and magnetic fields. Forms of electromagnetic radiation are short wavelengths such as
gamma rays and X-rays.
9. Define and give an example of a system. Distinguish among the inputs, flows (throughputs), and
outputs of a system. What is feedback? What is a feedback loop? Distinguish between a positive
feedback loop and a negative (corrective) feedback loop in a system, and give an example of each.
• A system is a set of components that function and interact in some regular way
• Most living systems have the following key components: inputs of matter and energy from the
environment, flows or throughputs of matter and energy within the system, and outputs of matter
and energy to the environment.
10. What are this chapter’s three big ideas? Relate the three principles of sustainability to the Hubbard
Brook Experimental Forest controlled experiment.
See page 37 and the Hubbard Brook Experiment. Student answers should slightly vary.
Chapter 2: Science, Matter, and Energy
• The three big ideas of this chapter:
o There is no doing away with matter. According to the law of conservation of matter, no atoms
are created or destroyed whenever matter undergoes a physical or chemical change. Thus, we
Critical Thinking
1. What ecological lesson can we learn from the controlled experiment on the clearing of forests
described in the Core Case Study that opened this chapter?
2. Suppose you observe that all of the fish in a pond have disappeared. Explain how you might use the
scientific process described in the Core Case Study and in Figure 2.2 to determine the cause of this fish
kill.
Answers will vary but the steps in Figure 2.2 for the scientific process should be followed.
Observation: the fish kill; Question: What caused the fish to die? Hypothesis: Maybe the dissolved
3. Respond to the following statements:
a. Scientists have not absolutely proven that anyone has ever died from smoking cigarettes.
b. The natural greenhouse theory—that certain gases such as water vapor and carbon dioxide warm
the lower atmosphere—is not a reliable idea because it is just a scientific theory.
(a) The medical and scientific evidence that links smoking to premature death caused by a number of
pathological conditions is overwhelming. As we are exposed to many chemical hazards in our
4. A tree grows and increases its mass. Explain why this is not a violation of the law of conservation of
matter.
The growth of a tree is an example of a chemical change or chemical reaction. Small inorganic
5. If there is no “away” where organisms can get rid of their wastes because of the law of conservation of
matter, why is the world not filled with waste matter?
Just like when small molecules are combined to form larger compounds, as in the case of the growth of
a tree, when larger compounds are broken down they release smaller molecules back into the
6. Someone wants you to invest money in an automobile engine, claiming that it will produce more
energy than the energy in the fuel used to run it. What is your response? Explain.
That is not a good investment! The first law of thermodynamics states that energy can be changed from
7. Use the second law of thermodynamics to explain why we can use oil only once as a fuel, or in other
words, why we cannot recycle its high-quality energy.
The second law of thermodynamics states that when energy changes from one form to another, some
8. Imagine that for one day (a) you have the power to revoke the law of conservation of matter, and (b)
you have the power to violate the first law of thermodynamics. For each of these scenarios, list three
ways in which you would use your new power. Explain your choices..
(a) Student answers will vary but could include: make more oil to offset the world shortage; produce
Global Environment Watch Exercise
Starting on the GREENR home page, under Browse Issues and Topics, choose Forests and Deforestation
from the Resource Management category. Browse the articles listed there and find one that involves a
controlled experiment or some other form of scientific research in a forest. Determine what the hypothesis
was that the researchers were testing. Briefly summarize their research methods and any conclusions that
were reached. Was the research similar in any way to that described in the Core Case Study?
One article in the above categorization addresses the effect that deforestation in having in terms of rising
temperatures and weather anomalies in Islamabad.
Chapter 2: Science, Matter, and Energy
Massive deforestation causing rise in Islamabad. (Brief article)
Technology Times, Jul 27, 2014. Reading Level (Lexile):1540
Data Analysis
1. In what year did the calcium loss from the experimental site begin a sharp increase? In what year did it
peak? In what year did it again level off?
2. In what year were the calcium losses from the two sites closest together? In the span of time between
1963 and 1972, did they ever get that close again?
3. Does this graph support the hypothesis that cutting the trees from a forested area causes the area to lose
nutrients more quickly than leaving the trees in place? Explain.