Introduction to Science Unit 1

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

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

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

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.

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

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

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

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?

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

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

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

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

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)

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

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

Write in scientific notation x x x x 10 5

Write x 10 4 in standard notation 1.287,

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

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

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

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

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.

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

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

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)

Models (cont’d)

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!

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