Presentation on theme: "Science Process, Graphing, SI System"— Presentation transcript:
1 Science Process, Graphing, SI System Unit 1Science Process, Graphing, SI System
2 Science Pure Science versus Technology Pure science is the study of the natural worldTechnology is applied science. Use of pure science knowledge to make an application or make something new.
3 Scientific Theories and Laws Scientific Theory- is an explanation of a natural event that has been tested by repeated observations.Scientific Law- states a repeated observation about nature. Has been tested and always holds true.
4 Description versus Math Qualitative Statements: describe events in nature. QualitiesExample: the effects of gravity on falling bodies.Data: collected in the form of statements describing observationsQuantitative Statements: laws and theories stated as mathematic equations. Mathematics is the language of science that is universal.Data: Use of equations, measurements, numbers
5 Models Model is a representation of an object or event. Example: cell model, model of an atom, molecule
6 Critical Thinking!Critical Thinking: applying logic and reason to solve problems.Experimental Design Format:ObserveQuestionHypothesisTest/ExperimentCollect/Analyze DataDraw Conclusions
7 Observations and Inferences Observations can be direct or indirect.Direct: made by using the 5 senses.What you see, hear, taste, touch, or smell.Indirect: Made by making a measurementExamples: length, temperature, mass, volumeInferences: educated guesses that explain an event. Basis for hypothesis statements
8 How Do You Get Started…… Make an Observation and then ask a Question.Question:Identifies the problemOnly asks one thing at a time.Stated clearlyLooks for a specific outcome.
9 Variables and Controls Variable: part that is changed in an experimentIndependent variable:The part that you purposely change in an experiment.Graphed on the x-axis in line graphs (horizontal axis)Dependent Variable:The part that changes as a result of what was manipulated.Graphed on the y-axis in line graphs (vertical)Control: experimental set-up where no factors are changed. Comparison Group.
10 HypothesisA possible explanation for a set of observations or answer to a questionIf/Then formatA formal hypothesis does not use first person terminology No personal pronouns.It should include the independent variable (factor that is changed) followed by the dependent variable (what changed in response).
11 Hypothesis Statement Format If (the independent variable) is (describe how you change it), the (dependent variable) will (describe the effect).If __ is __, then ___ will ___.
12 Setting up the Experiment… Procedure: Well defined set of step by step instructions. ( No personal Pronouns)Includes an experimental group set-up to test (independent variable change).Includes a control group.Identifies the constantsConstant- factors that are given to both the experimental group and the control group.**Remember that only one factor will be different for the experimental group. All other factors should be the same.
13 Collecting Data…..Qualitative: Description in the form of a paragraph, non measured, can be in a chart.Quantitative: Measured values, in the form of charts and graphs
14 Types of GraphsLine Graph: usually used to show changes over time, or data that changesBar Graphs: used when comparing data for several different individual items or events.Pie Chart: used when comparing parts of a whole
15 Graphing Data….. Remember: independent variable should be graphed on the x-axisdependent variable on the y-axis.yx
16 Drawing Conclusions…. Paragraph format: Restatement of Hypothesis Claim: based on dataEvidence: site specific dataReason statement: give reason for claimFormal writing format based on fact. Not opinion basedNo personal Pronouns
17 SI System Based on the metric system Units of 10International use by scientist to communicate data.7 Base UnitsLength meter mMass kilogram kgTime second sTemperature kelvin KElectric Current ampere AAmount of a substance mole molLuminous intensity candela cd
18 Derived Units Combinations of the base units: Examples: speed, density, weight, force, area, volume
19 SI Prefixes….To avoid the use of a lot of decimal places and zeroes we use metric prefixes to express very large and very small amounts.Are all multiples of 10
20 Common Metric Prefixes Memorize the basics and their power of 10Milli mCenti cDeci 0.1 dBase 1.0 Base Unit (Meter, Liter, Gram)Deka 10 dKHecto 100 hKilo K
21 Prefix Symbol Numerical Exponential MultiplierPrefix Symbol Numerical ExponentialYotta Y 1,000,000,000,000,000,000,000,zetta Z ,000,000,000,000,000,000,exa E ,000,000,000,000,000,pta P ,000,000,000,000,tera T ,000,000,000,giga G ,000,000,Mega M ,000,kilo k ,hecto hdeca dano prefix means:deci d ¯1centi c ¯2milli m ¯3micro µ ¯6nano n ¯9pico p ¯12femto f ¯15atto a ¯18zepto z ¯21yocto y ¯24
22 Common MeasurementsLength: The straight-line distance between two pointsMass: a measure of the amount of matter in an objectVolume: a measure of the space an object takes up or the capacity of a containerWeight: the force that gravity pulls on a quantity of matter.
23 Temperature Celsius to Kelvin Conversions: Celsius and Fahrenheit C = 5/9(F-32)F = (9/5C) + 32
24 Dimensional Analysis and Conversions If you are converting to a smaller unit, multiply.If you are converting to a larger unit, divide.100cm1.85m x = 185 cm1m
25 Keys For Success With Dimensional Analysis Must Use Correct Conversion Factor** know the prefixes and what they stand forDon’t forget to treat the Units of Measure just like numbers (Canceling out the U/M’s)Set up equations so X is a numerator.
26 Conversion Factors of One 1 cm3 = 1ml of space1g of water takes up 1ml of space or 1 cm3
27 Scientific NotationScientific Notation: a value written as a simple number multiplied by a power of 10.
28 Scientific Notation Steps Shortcut Steps:Put the decimal between the first two numbers.Count the number of places you moved the decimal and that becomes the power of 10.When a quantity smaller than one is converted the power becomes negative. (The decimal moves to the right)
29 Examples of Scientific Notation cm = 4.8 x 10-4cm35,000,000 mm = 3.5 x 107mm
30 Calculators and Scientific Notation E valuesExample: x 1043.12E4The E value is the exponent power of 10.
31 Significant FiguresSignificant Figures: the digits in a measurement that are known for certain.Precision: The degree of exactness of a measurement. Depends on the instrument used.Accuracy: the extent to which a measurement approaches the true value.Rounding to get significant figures:Always round to the even number.Example: = 3.2
32 Sig Fig RulesOnly keep the number of digits in a number that are known to be accurateWhen doing math, the answer can not be more precise that the least precise measurement used in the calculation.
33 Sig Fig’s: Why???? Precise measurement can be important! Historical Perspective: Hubble TelescopeSave time and computations of needless numbersWhy multiply m when the measurement is only accurate to 1.34m?
34 Instrument Precision Triple Beam Balance = 0.1g Meter Stick = 1mm Measure of MassMeter Stick = 1mmLengthTime = 0.01 sSecondGraduated Cylinder = 0.1mL to 1mL depending on size used.VolumeCan also be solid volume = 0.001m or 1mmThermometer = 1C
35 SI RulesAll measurements must have a unit of measure attached to the end.Zero’s mean something!No naked decimalsPut a zero in front 0.5cmZeroes at the end indicate the accuracy of the measurement5.6 is less precise than but only put the 00’s if measurement is that precise.