APES DO NOW• Turn in Tragedy of the Commons

• List the main environmental problems facing the world today.

• List the CAUSES of those problems.

Scientific Method

StepsIndependent vs. Dependent Variables

Control vs. Constant

Scientific Method

1. Question or Problem?2. Background Research3. Hypothesize4. Create Procedure +

Experiment5. Analyze Data + Results6. Conclusion

What is a variable?

• Effects of vitamin C on life span• Effect of fertilizer on plant growth• Effect of drug dosage on symptom severity• Effect of temperature on dissolved oxygen

Types of Variables

Your Turn!

Practice Identifying Variables• Students of different ages were given the same

jigsaw puzzle to put together. They were timed to see how long it took to finish the puzzle.

• Dependent variable: • Independent variable:• Constants:

time

ages

Same puzzle

Inductive vs. Deductive Reasoning*

Inductive = from specific to the general, starts from observation + evidence and leads to conclusion• Example: that every time you eat a hot dog with chili and onions, you get a stomachache.

Using inductive reasoning, you could logically conclude that the chili dogs cause indigestion, and that you should probably stop eating them.

Deductive = moves from a conclusion to the evidence for that conclusion• Example: All men are mortal. Socrates is a man.

Therefore, Socrates is mortal.

Chemistry Review• Matter • Elements • Atoms protons, neutrons, electrons• Compounds• Cations and Anions• Mixtures: homogeneous (solutions = solute + solvent)

and heterogeneous • Atomic number, Mass number • Isotopes

Energy Types• POTENTIAL (stored) vs. KINETIC (motion)• Law of Conservation of Matter

Energy LoopsPositive Feedback Loop• End result is often

explosive or amplifying• “cummulative

causation”• EX: contractions, blood

clotting, fission

Negative Feedback Loop• End result is often

equilibrium• “homeostasis”• EX: thermostat

Laws of Thermodynamics

• 1st Law: energy cannot be created nor destroyed, it only changes forms– Deals with quantity of energy

• 2nd Law: “Entropy Rules”, amount of useable energy decreases as energy changes forms, 10% gets transferred, 90% dissipated – Deals with quality of energy (high vs. low)

Energy TransfersConduction – through direct contact

Convection – by molecular movement

Radiation – by wave energy

Biology Review A human body contains trillions of cells, each with an identical set of genes.

Each human cell (except for red blood cells) contains a nucleus.

Each cell nucleus has an identical set of chromosomes, which are found in pairs.

A specific pair of chromosomes contains one chromosome from each parent.

Each chromosome contains a long DNA molecule in the form of a coiled double helix.

Genes are segments of DNA on chromosomes that contain instructions to make proteins—the building blocks of life.

The Electromagnetic Spectrum

Fig. 2-11, p. 45

Systems Have Inputs, Flows, and Outputs

• System– 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