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Introduction to Science Unit 1

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The Nature of Science Attempt to answer questions about the natural world by: Exploring the unknown Explaining the known Experimenting to test theories or confirm facts

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3 Main Branches of Science Biological- Botany, Ecology, Zoology, etc. Physical- Physics (motion), Chemistry (matter) Earth- Geology, Astronomy, Meteorology

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The Way Science Works: Scientific Method Steps: 1.Making observations 2.Asking questions 3.Forming a hypothesis; making a prediction 4.Testing the hypothesis through experimentation 5.Collecting and analyzing data from experiment 6.Drawing conclusion(s) from data 7.Communicating data to peers or public

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Scientific Method (cont’d) 1 question investigated at a time. Controlled experiments- compare experimental group (variable) to control group (lacks variable). *independent variable= variable/factor tested *dependent variable= variable measured quantitatively (numbers) Experiments can only disprove an hypothesis.

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Scientific Thinking Inference= conclusion drawn from previous data, not on direct observation. Theory= explains why something happens. Law= describes how something works.

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Units of Measurement- System International (SI) Units Quantity Base Unit Abbreviation Length Mass Time Temperature Volume

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Metric System (based on 10) based on powers of 10PrefixSymbolMeaning Multiply base unit by... kilo-thousand1,000 hecta-hundred1,00 deca-ten10 --------BASEUNIT---------------------------- deci-tenth0.1 centi-hundredth0.01 milli-thousandth0.001 pico-millionth0.000001 (5 zeros!) nano-billionth0.000000001 (8 zeros!) BIGGER SMALLER

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Metric Conversions (Only SI units are used to express scientific data) To convert from 1 unit to another: 1. Identify given unit; unknown unit. 2. Use dimensional analysis to compare known to unknown unit (factor-label method) Ex. How many pounds are in 1000 grams?

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How many meters is 800 km? KnowWant Don’t want

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An object’s mass is 250 kg. What is its mass in grams?

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Organizing Data: Graphs 1. Line Graph: for continuous data 2. Bar Graph: compares similar data for several things 3. Pie Graph: compares parts of a whole Our Ages Favorite Stores Car Speed

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Graphing Data Independent Variable: changed by scientist; x-axis Dependent Variable: “depends” on independent variable; y-axis Time Distance (m)

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How to Make a Line Graph 1. Label x-axis with independent variable 2. Label y-axis with dependent variable 3. Choose increments to represent data on each axis. 4. Plot points. 5. Connect points. 6. Name graph. Time (s) Distance (m)

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TimeDistance 0 s0 m 30 s2 m 60 s5 m 90 s11 m

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Scientific Notation Reduces # of 0’s in very large or small numbers. Expresses simple #’s x power of 10. (simple # = 1 - 10)

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Write 28750.9 in scientific notation. 1.2.87509 x 10 -5 2.2.87509 x 10 -4 3.2.87509 x 10 4 4.2.87509 x 10 5

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Write 2.87509 x 10 4 in standard notation 1.287,509. 2.28750.9 3.2875.09 4.28.7509

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Calculating Scientific Notation (Follow math rules for powers of 10) *multiplication= add powers of 10 **division= subtract powers of 10 ex. 7.2 x 10 -9 1.2 x 10 2 7.2 x 10 -9 1.2 x 10 2 sci notation = 6 x 10 -11

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Significant Figures Number of meaningful digits in a quantity. Significant figures: 1. Non-zero digits are always significant. ex. 1246 (4 SF) 2. Zeros between nonzeros. ex. 1206 (4 SF) 3. Zeros to right of decimal (“trailing zeros”) ex. 0.1200 (4 SF)

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Significant Figures (cont’d) Significant figures are not: 1. Space holding zeros in digits less than 1. ex. 0.09060 (4 SF) 2. Trailing zeros in a whole number ex. 83,000 (2 SN)

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So… How many sig figs are in the following: 83000 ____ SN 0.000800 ____ SN 8.800 ____ SN 800 ____ SN

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Precision vs Accuracy Science measurements should be: Precise: the degree to which an instrument or process will repeat the same value. Accurate: the degree of closeness to true value.

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The Correlation Method Correlation: associations between 2 events ex: width of a tree ring and drought Used when experimentation is not possible ex: “What was the Earth’s climate 60 x 10⁸ years ago?” Do not prove cause and effect relationships between 2 variables

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Scientific Habits of Mind Traits of a good scientist: Skepticism- don’t believe everything they’re told Open to new ideas Honesty (even if their hypothesis is wrong) Creative Curiosity

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Scientific Models Models: representations of systems Physical: 3-D, touchable Graphical: show positions or amounts (think maps) Conceptual: verbal or graphical explanation of how something works (think concept map, diagrams) Mathematical: use numbers and equations (hurricane predictions)

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Models (cont’d)

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Statistics Statistics: collection and classification of data (numbers) Provides info for analysis Uses mean (average) and Distribution: arrangement of numbers which creates a pattern Probability: the chance something will occur Risk: probability of an unwanted outcome ex: If you don’t study for your next test, you risk failing it!

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Decision Making Process for making knowledgeable decisions Involves: gathering info and looking at consequences, considering values: AestheticBeautiful or pleasing EconomicGain or loss of money or jobs Ethical/moralWhat is right or wrong EnvironmentalProtection of natural resources

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