1. Science, Matter, Energy, and Systems
Chapter 2

2. Core Case Study: Carrying Out a Controlled Scientific Experiment
Page 23
F. Herbert Bormann, Gene Likens, et al.: Hubbard Brook Experimental Forest in NH (U.S.)
Compared the loss of water and nutrients from an uncut forest (control site) with one that had been stripped (experimental site)

3. Controlled field experiment to measure the effects of deforestation on the loss of water and soil nutrients from a forest. V–notched dams were built into the impenetrable bedrock at the bottoms of several forested valleys (left) so that all water and nutrients flowing from each valley could be collected and measured for volume and mineral content. These measurements were recorded for the forested valley (left), which acted as the control site. Then all the trees in another valley (the experimental site) were cut (right) and the flows of water and soil nutrients from this experimental valley were measured for 3 years.

4. 2-1 Science Is a Search for Order in Nature
Identify a problem
Find out what is known about the problem
Ask a question to be investigated
Gather data
Hypothesize
Make testable predictions
Keep testing and making observations
Accept or reject the hypothesis

5. Scientific method
There are many types of scientific methods used to gather data,
 formulate hypotheses, state theories and laws and, then test them.
 Observation leads to a hypothesis, then to an experiment that 
produces results, which lead to a conclusion.
In an experimental group, one chosen variable is changed.
In a control group, the chosen variable is not changed. 
Good experiments have two essential characteristics: a single variable is tested, and a control is used.
The variable is the factor that changes in an experiment in order to test a hypothesis.
To test for one variable, scientists usually study two groups or situations at one time, with the variable being the only difference between the two groups.

6. The experimental group is the group in the experiment that is identical to the control group except for one factor and is compared with controls group.
The control group is the group in the experiment that serves as a standards of comparison with another group to which the control group is identical except for one factor.
Data is any pieces of information acquired through observation or experimentation.
Organizing data into tables and graphs helps scientists analyze the data and explain the data clearly to others.
Graphs are often used by scientists to display relationships or trends in the data.

7. Communicating Results
Scientists publish their results, sometimes in scientific articles, to share what they have learned with other scientist.
Scientific articles include the question the scientist explored, the reasons why the question is important, background information, a precise description of how the work was done, the data collected, and the scientist’s interpretation of the data.

8. The Correlation Method
The correlation method is used when the use of experiments to answer questions is impossible or unethical, scientists test predictions by examining correlations.
Correlation is the linear dependence between two variables.

9. The Correlation Method
An example is the relative width of a ring on a tree trunk is a good indicator of the amount of rainfall the tree received in a given year.
Trees produce wide rings in rainy years and narrow rings in dry years.
This method was used to help scientists investigate why the settlers at Roanake Island all died and why many died at the Jamestown Colony.

10. The Correlation Method
The Scientists concluded that the settlers may have been the victims of unfortunate timing.

11. 2-1 Scientists Use Reasoning, Imagination, and Creativity to Learn How Nature Works
Important scientific tools
Inductive reasoning
Inductive reasoning uses specific observations and measurements to arrive at a general conclusion.
Deductive reasoning
Deductive reasoning uses logic to arrive at a specific conclusion based on a generalization.
Scientists also use
Intuition
Imagination
Creativity

12. 2-1 Science Is a Search for Order in Nature (2)
Important features of the scientific process
Curiosity
Skepticism
Openness through Peer review
Reproducibility
intellectual honesty
Openness to new ideas
imagination and creativity

13. Scientific Habits of Mind
The third habit of mind is an (3) openness to new ideas. Good scientists keep an open mind to how the world works.
Another habit of mind is (4) intellectual honesty. A good scientist is willing to recognize the results of an experiments even though it may mean that his or her hypothesis was wrong.

14. Scientific Habits of Mind
Good scientists tend to share several key habits of mind, or ways of approaching and thinking about things.
The first habit of mind is (1) curiosity. Good scientists are endlessly curious which drives them to observe and experiment.
The second habit of mind is (2) skepticism. This means that good scientists don’t believe everything that they are told.

15. Scientific Habits of Mind
Lastly, good scientists share (5) imagination and creativity.
They are not only open to new ideas, but able to conceive new ideas themselves.
They have the ability to see patterns where other do not or can imagine things that other cannot.
This allows for good scientists to expand the boundaries we know.

16. 2-1 Science Focus: Easter Island: Revisions to a Popular Environmental Story
Some revisions in a popular environmental story
Read Pg. 27
Polynesians arrived about 800 years ago
Population may have reached 3000
Used trees in an unsustainable manner, but rats may have multiplied and eaten the seeds of the trees

18. Scientific Theories and Laws Are the Most Important Results of Science
Scientific theory
Widely tested
Supported by extensive evidence
Accepted by most scientists in a particular area
Scientific law, law of nature
Paradigm shift
occur when new discoveries overthrow well­accepted scientific theory.

19. The Results of Science Can Be Tentative, Reliable, or Unreliable
Tentative science, frontier science
 is scientific results that have not been confirmed; sound science or consensus science  results from scientific results that have been well tested and are widely accepted. 
Reliable science
Unreliable science

20. Environmental Science Has Some Limitations
Particular hypotheses, theories, or laws have a high probability of being true while not being absolute
Bias can be minimized by scientists
Statistical methods may be used to estimate very large or very small numbers
Environmental phenomena involve interacting variables and complex interactions
Scientific process is limited to the natural world

21. Science Focus: Statistics and Probability
Collect, organize, and interpret numerical data
Probability
The chance that something will happen or be valid

22. How Scientists use Statistics
Statistics is the collection and classification of data that are in the form of numbers.
Scientists rely on and use statistics to summarize, characterize, analyze, and compare data.
Statistics is actually a branch of mathematics that provides scientists with important tools for analyzing and understanding their data.
Scientists use statistics to describe statistical populations.
A statistical population is a group of similar things that a scientist is interested in learning about.

23. Statistical populations are composed of similar individuals, but these individuals often have different characteristics.
A mean is the number obtained by adding up the data for a given characteristic and dividing this sum by the number of individuals.
The mean provides a single numerical measure for a population and allows for easy comparison.

24. Distribution is the relative arrangement of the members of a statistical population, and is usually shown in a graph.
The graphs of many characteristics of populations, such as the heights of people, form bell-shaped curves.
A bell shaped curve indicates a normal distribution where the data is grouped symmetrically around the mean.

25. What is the Probability?
Probability is the likelihood that a possible future event will occur in any given instance of the event
P= total ways a specific outcome will happen
total number of possible outcomes
Probability is usually expressed as a number between 0 and 1 and written as a decimal rather than as a fraction.
However, there must be a large enough sample size in order to obtain accurate results.

26. Understanding Risk Risk is the probability of an unwanted outcome.
People often worry about big oil spills, but as the pie chart below shows, there is a much greater risk of oil pollution from everyday sources.

27. The most important risk we consider is the risk of death.
Most people overestimate the risk of dying from sensational causes, such as plane crashes, but underestimate the risk from common causes, such as smoking.
Likewise, most citizens overestimate the risk of sensational environmental problems and underestimate the risk of ordinary ones.

28. 2-2 What Is Matter?
Concept 2-2 Matter consists of elements and compounds, which are in turn made up of atoms, ions, or molecules.

29. Matter Consists of Elements and Compounds
Has mass and takes up space
Elements
Unique properties
Cannot be broken down chemically into other substances
Compounds
Two or more different elements bonded together in fixed proportions

30. Matter Occurs in Various Physical Forms
Gas
Liquid
Solid

33. Atoms, Ions, and Molecules Are the Building Blocks of Matter (1)
Atomic theory
Subatomic particles
Protons (p) with positive charge and neutrons (0) with no charge in nucleus
Negatively charged electrons (e) orbit the nucleus
Mass number
Protons plus neutrons
Isotopes
Forms of an element having the same atomic number(protons) but different number of mass number (proton + neutrons).

34. Atoms, Ions, and Molecules Are the Building Blocks of Matter (2)
Gain or lose electrons
Form ionic compounds pH
Measure of acidity
H+ and OH-

36. Atoms, Ions, and Molecules Are the Building Blocks of Matter (3)
Two or more atoms of the same or different elements held together by chemical bonds
Chemical formula

37. Organic Compounds Are the Chemicals of Life
Inorganic compounds
Salt, carbon dioxide, water
Organic compounds
Hydrocarbons and chlorinated hydrocarbons
Simple carbohydrates
Macromolecules: complex organic molecules
Complex carbohydrates
Proteins
Nucleic acids
Lipids

38. Some Forms of Matter Are More Useful than Others
High-quality matter
Low-quality matter
Figure 2.6
Examples of differences in matter quality. High-quality matter (left column) is fairly easy to extract and is highly concentrated; low-quality matter (right column) is not highly concentrated and is more difficult to extract than high-quality matter.

39. Matter Comes to Life through Genes, Chromosomes, and Cells
Cells: fundamental units of life
Genes: sequences of nucleotides within the DNA
Chromosomes: composed of many genes

40. 2-3 How Can Matter Change?
Concept 2-3 When matter undergoes a physical or chemical change, no atoms are created or destroyed (the law of conservation of matter).

41. Matter Undergoes Physical, Chemical, and Nuclear Changes
Physical change, change in physical appearance; chemical composition doesn’t change
Chemical change, chemical reaction; new product created
Nuclear change
Natural radioactive decay
Radioisotopes: unstable
Nuclear fission
Nuclear fusion

44. We Cannot Create or Destroy Matter
Law of conservation of matter
Matter consumption
Matter is converted from one form to another

45. 2-4 What is Energy and How Can It Be Changed?
Concept 2-4A When 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 2-4B Whenever energy is changed from one form to another, we end up with lower- quality or less usable energy than we started with (second law of thermodynamics).

46. Energy Comes in Many Forms
Kinetic energy
Heat
Transferred by radiation, conduction, or convection
Electromagnetic radiation
Potential energy
Stored energy
Can be changed into kinetic energy

47. Electromagnetic Spectrum

48. Some Types of Energy Are More Useful Than Others
High-quality energy
Low-quality energy

49. Energy Changes Are Governed by Two Scientific Laws
First Law of Thermodynamics
Energy input always equals energy output
Second Law of Thermodynamics
Energy always goes from a more useful to a less useful form when it changes from one form to another
Energy efficiency or productivity

50. Solar energy Waste heat Waste heat Waste heat Waste heat
Mechanical
energy
(moving,
thinking, living)
Chemical
energy
(photosynthesis)
Chemical
energy
(food)
Solar
energy
Waste
heat
Waste
heat
Waste
heat
Waste
heat

51. 2-5 What Are Systems and How Do They Respond to Change?
Concept 2-5A Systems have inputs, flows, and outputs of matter and energy, and their behavior can be affected by feedback.
Concept 2-5B Life, human systems, and the earth’s life support systems must conform to the law of conservation of matter and the two laws of thermodynamics.

52. Systems Have Inputs, Flows, and Outputs
Inputs from the environment
Flows, throughputs
Outputs

54. Systems Respond to Change through Feedback Loops
Positive feedback loop
Negative, or corrective, feedback loop