1. Unit 1 Powerpoint Review for Chapter 2

2. What Is Science? Science is a pursuit of knowledge about how the world works Scientific data is collected by making observations and taking measurements Observations involve the five senses, and help answer questions or problems

3. Observation QualitativeQualitative –of, relating to, or involving quality or kind –ie.: red, hot, burns quickly, etc. QuantitativeQuantitative –of, relating to, or involving the measurement of quantity or amount –ie.: 350 degrees Celsius, 5 inches, etc.

4. Vocabulary Experiment –A procedure to study a phenomenon under known conditions –Must have a Control Hypotheses –A possible explanation of something observed in nature. Model –An approximate representation of a system being studied.

5. Theory and Law Scientific Theory –A hypothesis that has been supported by multiple scientists’ experiments in multiple locations A Scientific Law –a description of what we find happening in nature over and over again in a certain way

6. Scientific Laws Law of Conservation of Matter –Matter can be changed from one form to another, but never created or destroyed. Atomic Theory of Matter –All matter is made of atoms which cannot be destroyed, created, or subdivided.

7. Accuracy and Precision Accuracy –The extent to which a measurement agrees with the accepted or correct value for that quantity. Precision –A measure of reproducibility, or how closely a series of measurements of the same quantity agrees with one another.

8. Reasoning Inductive Reasoning –Uses observations and facts to arrive at hypotheses –All mammals breathe oxygen. Deductive Reasoning –Uses logic to arrive at a specific conclusion based on a generalization –All birds have feathers, Eagles are birds, therefore All eagles have feathers.

9. Scientific Methods What is the question to be answered? What relevant facts and data are known? What new data should be collected? After collection, can it be used to make a law? What hypothesis can be invented to explain this? How can it become a theory?

10. Experiments Variables are what affect processes in the experiment. Controlled experiments have only one variable Experimental group gets the variable Control group does not have the variable –Placebo is a harmless pill that resembles the pill being tested. –In double blind experiments, neither the patient nor the doctors know who is the control or experiment group.

11. Systems A system is a set of components that function and interact in some regular and predictable manner Human body, a river, an economy, The Earth! –The earth is a closed system for matter and an open system for energy

12. Feedback Loops A feedback loop occurs when an output of a system is fed back as an input (two kinds) –Positive loops are runaway cycles where a change in a certain direction causes further change in the same direction –Negative loops occur when a change in a certain direction leads to a lessening of that change

13. Resource Consumption and Environmental Problems Underconsumption Overconsumption –Affluenza: unsustainable addiction to overconsumption and materialism.

14. The pH (potential of Hydrogen) is the concentration of hydrogen ions in one liter of solution. Figure 2-5

15. Compounds and Chemical Formulas Chemical formulas are shorthand ways to show the atoms and ions in a chemical compound. –Combining Hydrogen ions (H + ) and Hydroxide ions (OH - ) makes the compound H 2 O (dihydrogen oxide, a.k.a. water). –Combining Sodium ions (Na + ) and Chloride ions (Cl - ) makes the compound NaCl (sodium chloride a.k.a. salt).

16. Cells: The Fundamental Units of Life Cells are the basic structural and functional units of all forms of life. –Prokaryotic cells (bacteria) lack a distinct nucleus. –Eukaryotic cells (plants and animals) have a distinct nucleus. Figure 2-6

17. Macromolecules, DNA, Genes and Chromosomes Large, complex organic molecules (macromolecules) make up the basic molecular units found in living organisms. –Complex carbohydrates –Proteins –Nucleic acids –Lipids Figure 2-7

18. Matter Quality Matter can be classified as having high or low quality depending on how useful it is to us as a resource. –High quality matter is concentrated and easily extracted. –low quality matter is more widely dispersed and more difficult to extract. Figure 2-8

19. CHANGES IN MATTER Matter can change from one physical form to another or change its chemical composition. –When a physical or chemical change occurs, no atoms are created or destroyed. Law of conservation of matter. –Physical change maintains original chemical composition. –Chemical change involves a chemical reaction which changes the arrangement of the elements or compounds involved. Chemical equations are used to represent the reaction.

20. Chemical Change Energy is given off during the reaction as a product.

21. ENERGY Energy is the ability to do work and transfer heat. –Kinetic energy – energy in motion heat, electromagnetic radiation –Potential energy – stored for possible use batteries, glucose molecules

22. ENERGY LAWS: TWO RULES WE CANNOT BREAK The first law of thermodynamics: we cannot create or destroy energy. –We can change energy from one form to another. The second law of thermodynamics: energy quality always decreases. –When energy changes from one form to another, it is always degraded to a more dispersed form. –Energy efficiency is a measure of how much useful work is accomplished before it changes to its next form.

23. Sustainable Low-Throughput Economies: Learning from Nature Matter-Recycling-and- Reuse Economies: Working in Circles –Mimics nature by recycling and reusing, thus reducing pollutants and waste. –It is not sustainable for growing populations.