Chapter 2

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

2. Section 1 The nature of Science

3. Easter Island • Easter Island (Rapa Nui) colonized by Polynesians 2,500 years ago. • Originally it had lush forests buy the Polynesians harvested all the trees. • The population flourished and soon the island was inhabited by up to 20,000 people. • When the resources completely disappeared, the residents of Easter Island hunted and ate each other. • Over the course of a couple hundred years, the population decreased to 2,000 people.

4. What is science and what do scientists do? • What is science and what do scientists do? • Science- an attempt to discover order in the natural world and use that knowledge to describe what is likely to happen in nature. • Things scientists do: Collect scientific data Scientists collect facts by making observations and taking measurements Conduct Experiments Scientists conduct many tests in which they repeatedly collect scientific data Formulate Hypotheses Many scientists come of with ideas that explain their observations Develop Models A method that scientists use to test their hypotheses is to make a model or a simulation of what is being studied

5. Results of Science • Peer Review • Peer Review is when fellow scientists (peers) read published experiments and can examine and criticize each others work • Theories • Scientific theories are not guesses or speculations • A scientific theory is a useful explanation of a process of phenomena • New evidence can modify, backup or even overturn theories • Scientific Laws • A scientific or natural law is something in nature that repeats itself thousands of times so that scientists can form concrete conclusions • An example of this would be the Second Law of Thermodynamics

6. How do scientists learn about nature? The scientific Process: • Observation: Nothing happens when you turn on your flashlight • Question: Why didn’t the light turn on? • Hypothesis: Perhaps the batteries are dead. • Test the Hypothesis: Replace the batteries. • Result: The flashlight still does not work • New Hypothesis: Perhaps the bulb is broken. • Experiment: Replace the bulb. • Result: The flashlight works. • Conclusion: The second hypothesis was correct.

7. Aspects of an experiment • Experiments have variables or factors that can influence every little part of them. • Scientists prefer controlled experiments where there is little interference

8. What type of reasoning do scientists use? • Inductive Reasoning Inductive reasoning is when a scientist uses observations and measurements to arrive at a conclusion or hypothesis • Deductive reasoning Deductive reasoning is when a scientist uses logic to arrive at a specific conclusion based on a generalization or premise

9. How valid are the results of science? • Scientists can prove and disprove things • Most things in science are not absolutely true • The words projection, scenarios and likely are preferred instead of words like prediction, forecast and will

10. What is the difference between frontier science and sound science? • Frontier Science is science that is based on preliminary results and often is controversial because it has not been widely tested • Sound Science is science that consists of data theories and laws which are generally more accepted by scientists

11. What is junk science and how can we detect it? • Junk science is scientific results that are presented as sound science but have not been tested enough to be valid at all • Some scientists and politicians badmouth valid science that does not support their agenda by calling it junk science

12. Section 2 Models and Behavior of Systems

13. Why are models of complex systems useful? • System- a set of components that function and interact in some regular and theoretical understandable manner • Systems have inputs, flows and outputs • Models are used to evaluate systems

14. How do feedback loops effect systems? • A feedback loop is when the output of a system is fed back as input and leads to a change in the system • A positive feedback loop is when a system changes further in the same direction Ex. Depositing money in a bank and gaining interest. The interest increases the balance which in turn increases the interest. • A negative or corrective feedback loop is when a system changes in the opposite direction Ex. Recycling aluminum cans. Old aluminum cans are melted down and made into new aluminum cans with minimal waste.

15. How do time delays effect complex systems? • Time delays occur often in complex systems. Ex. A smoker who is exposed to the toxins in the cigarette may not develop lung cancer for many years. • Time delays allow the problem or a factor in an experiment to build up until it reaches a threshold level which causes a fundamental shift in the experiment.

16. What is synergy and how does it affect complex systems • A synergistic interaction is when two or more processes interact so that the combined affect is greater than the sum of their separate affects. Ex. Two people can each lift 45 pounds. They work together and they can lift 100 pounds.

17. How can we anticipate environmental surprises? • Many times there are environmental surprises or discontinuities • When a threshold is crossed, surprises occur • We can deal with this by never doing just one thing

18. Section 3 Matter

19. What types of matter do we find in nature? • Matter- anything that has mass and takes up space • Two chemical forms of matter: Elements- the distinctive building blocks of matter that make up ever material substance Ex. N, H, P, Br Compounds- two of more different elements that are held together in fixed proportions by attractive forces call chemical bonds Ex. NaH2 Br4H2 HeF

20. What are nature’s building blocks? • Three things elements are made of: Atoms- the smallest unit of matter that exhibits the characteristics of an element Molecules- combinations of two or more atoms of the same or different elements held together by chemical bonds Ions- an electrically changed atom or combination of atoms

21. What are atoms made of? • Atoms are made up of different subatomic particles each having a different change • Parts of an atom Protons have a positive charge Electrons have an electric charge Neutrons have no charge • The atomic number of an element is equal to the number of protons in the nucleus or center of an atom • The mass number of an atom is the total number of neutrons and protons in the nucleus • Some elements have different forms that have the same atomic number but a different mass number, these are called isotopes Ex. Hydrogen-2

22. What are ions? • Ions are made when an element loses or gains electrons • Unlike atoms, ions are not neutral overall • Some atom tend to lose electrons and form ions, like metals • They are known as electron givers • Nonmetals tend to receive electrons and form ions • They are called electron receivers • The concentration of hydrogen ions in an element is known as its pH level • This determines whether it is an acid or a base

23. What holds the atoms and ions in a compound together? • Chemical bonds hold different compounds • Shorthand chemical formulas are used to show the number of atoms or ions of each type in a compound • Compounds made up of oppositely charged ions are called ionic compounds • Compounds made up of molecules of uncharged atoms are called covalent or molecular compounds

24. What are organic compounds? • Most of the chemicals in the human body are organic compounds • Organic compounds are organic because they have carbon in them • There are natural organic compounds like proteins and fats • There are also synthetic organic compounds like plastics and drugs

25. What are genes, chromosomes, and DNA molecules? • DNA- Deoxy Nucleic Acid • RNA- Ribo Nucleic Acid • Genes- specific sequences of nucleotides in a DNA molecule • Chromosomes- combinations of genes that make up a single DNA molecule with proteins

26. What are inorganic compounds? • Inorganic compounds are compounds that do not have carbon-carbon or carbon-hydrogen bonds Ex. Salt, Water, Carbon Dioxide

27. What are four states of matter? • Three physical states of matter: Solid Liquid Gas • Plasma is the fourth state of matter and is a high energy mixture of positively charged ions and negatively charged electrons

28. What is matter quality? • Matter quality- the measure of how useful a form of matter is to us as a resource • High quality matter is matter that is concentrated and is usually found near the surface of the earth • Low quality matter is watered down and can be found deep underground • The total amount of material needed to produce a certain amount of a product is called the material efficiency or resource productivity

29. Section 4 Energy

30. What is energy? • Energy- the capacity to do work and transfer heat • Two types of energy: Kinetic energy is energy that is possessed by matter because of its speed or velocity Potential energy is energy that is stored and available for use

31. What is electromagnetic radiation? • Electromagnetic radiation is a type of energy that is a wave • The distance between the peaks of an electromagnetic wave is called its wavelength • Radiation that has enough energy to change atoms into positively changed ions are called ionizing radiation • Other forms of radiation are called nonionizing radiation • Visible light is a form of nonionizing radiation

32. What is heat and how is it transferred? • Heat- the total kinetic energy of al the moving atoms, ions, or molecules within a given substance excluding all overall motion of the whole object • Temperature- the average speed of motion of the atoms, ions, or molecules in a sample of matter at a given moment • Heat can be transferred from one place to another

33. What is energy quality? • Energy quality- a measure of an energy sources ability to do useful work • High quality energy is concentrated and can do useful work • Low quality energy is dispersed and has little ability to d useful work

34. Section 5 The Law of Conservation of Matter

35. What is the difference between a physical and chemical change? • When matter is shifted so that its chemical composition is not changed, it undergoes a physical change • A chemical change, sometimes called a chemical reaction, occurs when the chemical composition of a compound changes

36. The law of conservation of matter: why there is no “away” • THE LAW OF CONSERVATION OF MATTER: MATTER CAN NEITHER BE CREATED OR DESTROYED • Translation- Everything that we use, eat, or throw away is still here in one form or another • There is no away, you cannot throw away matter forever because it changes

37. How do chemists keep track of atoms? • When an element changes its chemical composition, it still has to have the same amount of atoms • To measure this, scientists use a balanced chemical equation Ex. C + O2 = CO2

38. How harmful are pollutants? • Three factors that determine the severity of pollutants harmful effects: Concentration- this is the potency of a chemical and is expressed in PPM or parts per million Persistence- this is how long the chemical stays around in the air, water, and ground Chemical nature- this is how bad the chemical is and what it does • Three types of pollutants: Degradable- natural processes break down the chemicals so that they are at acceptable levels Slowly Degradable- these chemicals degrade but can take decades Nondegradable- chemicals that natural processes cannot break down

39. Section 6 Nuclear Changes

40. What is natural radioactivity? • The third type of change that matter can undergo is called a nuclear change • When isotopes emit particle, it is called radioactive decay • Unstable isotopes are called radioisotopes or radioactive isotopes • Two most common particles: Alpha particles- fast moving protons Beta particles- fast moving electrons

41. What is nuclear fission? • Nuclear fission- a change in which nuclei of certain isotopes with large mass numbers are split into lighter nuclei when struck by neutrons • One fission leads to another; this is called a chain reaction • An example of this is the atomic bomb

42. What is nuclear fusion? • Nuclear fusion- a nuclear change in which two isotopes of light elements such as hydrogen are forced together at extremely high temperatures until they fuse to become a heavier nucleus • Nuclear fusion is more difficult to initiate but also produces more energy • Fusion powers the stars

43. Section 7 Energy Laws: Two Rules We Cannot Break

44. What is the first law of thermodynamics? • Energy can neither be created nor destroyed • Is the same as the law of conservation of energy • Energy input equals energy output • Cannot get something for nothing

45. What is the second law of thermodynamics? • When energy is changed from one form to another, some of the useful energy is always degraded to lower quality, more dispersed, less useful energy • Translation- When energy is changed from one form to another, it changes to lower quality energy • Energy efficiency or energy productivity is how much useful work can be accomplished by a particular input of energy

46. Section 8 Matter and Energy Laws and Environmental Problems

47. What is a high-throughput economy? • A high throughput economy is a high waste economy • Most today’s countries add a lot of waste and heat to the environment • Eventually the amount of waste being produced will exceed the capacity of the environment and nature will no longer be able to dilute out pollutants

48. What is a matter-recycling-and-reuse economy? • A matter-recycling-and-reuse economy is an economy that reuses waste instead of dumping it into our environment • This gives us more times until the environment cannot handle our waste

49. What is a low-throughput economy? • A low-throughput economy is a low waste economy • It means people have to recycle, conserve energy and control population growth • This helps us maintain an environmental equilibrium

50. Sources • Living in the Environment Tyler Miller Jr. • www.wikipedia.org • www.webelements.com • www.antoine.frostburg.edu • http://webbook.nist.gov/chemistry/