Chapter 2 Notes
- 1. Chapter 2
- 2. Logical approach to solve problems Observe, collect data, formulate hypothesis, test hypothesis, formulate theories supported by data Steps may vary
- 3. Using your senses to collect information May make measurements May collect data Record of facts
- 4. Logical interpretation based on knowledge and experiences
- 5. In lab, you note observations, not inferences Inferences may be used in writing conclusions (lab reports) Let’s test your observation skills…….
- 7. Are there cars parked on the sides of the road? What color is the pickup truck driving on the road? Are there any minivans around? What does the blue sign say? What’s the speed limit? Are there any pedestrians?
- 9. On the next slide, state whether the statement is an observation or an inference.
- 10. 1. There is a representation of a face on one side of the coin. 2. The Latin word "Dei" means "God." 3. The coin was made by deeply religious people. 4. The date 1722 is printed on one side of the coin. 5. The coin was made in 1722. 6. The face on the coin is a representation of the nation's president.
- 13. Do you see former President Bill Clinton and Al Gore? Actually, it’s Clinton’s face twice with 2 different hair cuts!
- 14. Hint : There are 3 images. An old lady A young woman A man with a big brown mustache
- 15. They are the SAME length!
- 23. A Duck, Bunny, or BOTH?
- 24. This image contains a picture and a word. Do you see both of them?
- 26. Your brain!
- 27. Your right brain tried to say the color, but your left brain was reading the word.
- 29. They are all the same height!
- 30. The Landscape of Faces
- 31. How about now?
- 34. Testable statement Basis for making predictions and for carrying out further experiments “ If-then” statements
- 35. Model More than just a physical object Explanation of how phenomena occur and how data or events are related Ex: atomic model of matter (atoms) Theory Broad generalization that explains facts or phenomena
- 36. Quantitative information Represents quantities Quantity: Something that has magnitude, size, or amount Not the same as a measurement
- 37. Defined in terms of standards of measurement Have constant value, easy to preserve and reproduce, practical in size
- 38. SI Base Units Quantity Quantity Symbol Unit Name Unit Abbreviation Length l meter m Mass m kilogram kg Time t second s Temperature T kelvin K Amount of substance n mole mol Electric current I ampere A
- 39. SI Prefixes Prefix Unit Abbreviation Meaning/Example mega M 1Mm = 1,000,000m kilo k 1km = 1,000m hecto h 1hm = 100m deka da 1dam = 10m deci d 1m = 10dm centi c 1m = 100cm milli m 1m = 1,000mm micro μ 1m = 1,000,000 μ m nano n 1m = 1,000,000,000nm pico p 1m = 1,000,000,000,000pm
- 40. Derived SI Units Quantity Quantity Symbol Unit Unit Abbreviation Derivation Area A Square meter m 2 length x width Volume V Cubic meter m 3 length x width x height Density D Kilograms per cubic meter kg/m 3 mass / volume Molar Mass M Kilograms per mole kg/mol mass / amount of substance Concentration c Moles per liter M amount of substance / volume Molar Volume V m Cubic meters per mole m 3 /mol volume / amount of substance Energy E joule J force x length
- 41. Measure of a quantity of matter Often confused with weight Weight measure of the gravitational pull on matter
- 42. Amount of space occupied by an object Derived SI unit is cubic meters (m 3 )
- 43. The ratio of mass to volume (Mass divided by volume) Characteristic physical property of a substance Does NOT depend on size of sample Can be used as a property to identify a substance
- 44. Conversion factor- a ratio derived from the equality between two different units that can be used to convert from one unit to the other.
- 45. Accuracy Closeness of measurement to the correct or accepted value Precision Refers to the closeness of a set of measurements of the same quantity made in the same way
- 48. Rules: Zeros appearing between non-zero digits are significant. Zeros appearing in from of all non-zero digits are not significant. Zeros at the end of a number and to the right of a decimal point are significant. Zeros at the end of a number but to the left of a decimal point may or may not be significant. If a zero has not been measured or estimated, but is just a placeholder, it is not significant. A decimal point placed after zeros indicates that they are significant.
- 49. When you add or subtract decimals, the answer must have the same number of digits to the right as there are in the measurement having the fewest digits to the right of the decimal. For multiplication and division, the answer can have no more sig. figs. than are in the measurement with the fewest number of sig. figs.