1. CHAPTER 2
SCIENCE, MATTER, ENERGY & SYSTEMS

2. Three Big Ideas There is no away.
You cannot get something for nothing.
You cannot break even.

3. Matter Consists of Elements & 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

4. Atoms, Ions, & Molecules Are the Building Blocks of Matter
Atomic theory
All elements are made of atoms
Subatomic particles
Protons with positive charge and neutrons with no charge in nucleus
Negatively charged electrons orbit the nucleus
Atomic number
Number of protons in nucleus
Mass number
Number of protons plus neutrons in nucleus

5. Atoms, Ions, & Molecules Are the Building Blocks of Matter, cont.
Isotopes
Same element, different number of protons
Ions
Gain or lose electrons
Form ionic compounds pH
Measure of acidity
H+ and OH-

6. pH Scale
Figure 5 The pH scale, representing the concentration of hydrogen ions (H+) in one liter of solution is shown on the right-hand side. On the left side, are the approximate pH values for solutions of some common substances. A solution with a pH less than 7 is acidic, one with a pH of 7 is neutral, and one with a pH greater than 7 is basic. A change of 1 on the pH scale means a tenfold increase or decrease in H+ concentration. (Modified from Cecie Starr, Biology: Today and Tomorrow. Pacific Grove, CA: Brooks/Cole, © 2005)
Supplement 5, Figure 4

7. Organic Compounds Are the Chemicals of Life
Hydrocarbons and chlorinated hydrocarbons
Simple carbohydrates
Macromolecules: complex organic molecules
Complex carbohydrates
Proteins
Nucleic acids
Lipids
Inorganic compounds

8. Matter Forms Life through Genes, Chromosomes, & Cells
Cells: fundamental units of life; all organisms are composed of one or many cells
Genes
Sequences of nucleotides within DNA
Instructions for proteins
Create inheritable traits
Chromosomes: composed of many genes

9. Some Forms of Matter Are More Useful than Others
High Quality Matter
Highly concentrated
Near earth’s surface
High potential as a resource
Low quality matter has the opposite qualities

10. Matter Undergoes Physical, Chemical, & Nuclear Changes
Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed (the law of conservation of matter).
Physical change
No change in chemical composition
Chemical change, chemical reaction
Change in chemical composition
Reactants and products
Nuclear change
Natural radioactive decay
Radioisotopes: unstable
Nuclear fission
Nuclear fusion

11. Types of Nuclear Changes
Figure 2.9: There are three types of nuclear changes: natural radioactive decay (top), nuclear fission (middle), and nuclear fusion (bottom).
Fig. 2-9, p. 43

12. Energy Comes in Many Forms
Kinetic energy
Flowing water
Wind
Heat
Transferred by radiation, conduction, or convection
Electromagnetic radiation
Potential energy
Stored energy
Can be changed into kinetic energy
Sun provides 99% of earth’s energy
Warms earth to comfortable temperature
Plant photosynthesis
Winds
Hydropower
Biomass
Fossil fuels: oil, coal, natural gas

13. Energy Changes Are Governed by Two Scientific Laws
First Law of Thermodynamics (Law of Conservation of Energy)
Energy is neither created nor destroyed in physical and chemical changes
Second Law of Thermodynamics
Energy always goes from a more useful to a less useful form when it changes from one form to another

14. Energy Changes Are Governed by Two Scientific Laws
Incandescent light bulbs and internal combustion engines are very inefficient: produce wasted heat
Cellular respiration in mammals and birds is far less efficient than in amphibians, reptiles, insects & other members of the animal kingdom
Ex: Mammals typically consume five to 10 times (depends on the conditions) the amount of food energy as a reptile to maintain life processes

16. Systems Have Inputs, Flows, & Outputs
Set of components that interact in a regular way
Human body, earth, the economy
Inputs from the environment
Flows (throughputs) of matter and energy
Outputs to the environment

17. Inputs, Throughput, & Outputs of an Economic System
Figure 2.17: This diagram illustrates a greatly simplified model of a system. Most systems depend on inputs of matter and energy resources, and outputs of wastes, pollutants, and heat to the environment. A system can become unsustainable if the throughputs of matter and energy resources exceed the abilities of the system’s environment to provide the required resource inputs and to absorb or dilute the resulting wastes, pollutants, and heat.
Fig. 2-17, p. 48

18. Systems Respond to Change through Feedback Loops
Positive feedback loop
Causes system to change further in the same direction
Can cause major environmental problems
Negative, or corrective, feedback loop
Causes system to change in opposite direction

19. Positive vs. Negative Feedback Loops
Positive Negative

20. Positive Feedback Loop
Decreasing vegetation...
... which causes more vegetation to die.
... leads to erosion and nutrient loss...
Figure 2.18: This diagram represents a positive feedback loop. Decreasing vegetation in a valley causes increasing erosion and nutrient losses that in turn cause more vegetation to die, resulting in more erosion and nutrient losses. Question: Can you think of another positive feedback loop in nature?
Positive Feedback Loop
Fig. 2-18, p. 49

21. Negative Feedback Loop
House warms
Temperature reaches desired setting and furnace goes off
Furnace on
Furnace off
Figure 2.19: This diagram illustrates a negative feedback loop. When a house being heated by a furnace gets to a certain temperature, its thermostat is set to turn off the furnace, and the house begins to cool instead of continuing to get warmer. When the house temperature drops below the set point, this information is fed back to turn the furnace on until the desired temperature is reached again.
House cools
Negative Feedback Loop
Temperature drops below desired setting and furnace goes on
Fig. 2-19, p. 50

22. Time Delays & Tipping Points
Time delays vary between the input of a feedback stimulus and the response to it
Tipping point, threshold level
Causes a shift in the behavior of a system
Melting of polar ice
Population growth

23. System Effects Can Be Amplified through Synergy
Synergistic interaction, synergy
Two or more processes combine in such a way that combined effect is greater than the two separate effects
Helpful
Studying with a partner
Harmful
E.g., Smoking and inhaling asbestos particles