Unit 1 Science Process, Graphing, SI System. Science Pure Science versus Technology Pure science is the study of the natural world Technology is applied.

Unit 1Science Process, Graphing, SI

System

Science Pure Science versus Technology

Pure science is the study of the natural world

Technology is applied science. Use of pure science knowledge to make an application or make something new.

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.

Description versus Math

Qualitative Statements: describe events in nature. Qualities Example: the effects of gravity on falling bodies. Data: collected in the form of statements

describing observations Quantitative Statements: laws and

theories stated as mathematic equations. Mathematics is the language of science that is universal. Data: Use of equations, measurements, numbers

Models Model is a representation of an object

or event. Example: cell model, model of an atom,

molecule

Critical Thinking! Critical Thinking: applying logic and

reason to solve problems. Experimental Design Format:

Observe Question Hypothesis Test/Experiment Collect/Analyze Data Draw Conclusions

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

measurement Examples: length, temperature, mass, volume

Inferences: educated guesses that explain an event. Basis for hypothesis statements

How Do You Get Started……

Make an Observation and then ask a Question.

Question: Identifies the problem Only asks one thing at a time. Stated clearly Looks for a specific outcome.

Variables and Controls

Variable: part that is changed in an experiment Independent 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.

Hypothesis A possible explanation for a set of

observations or answer to a question If/Then format A 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).

Hypothesis Statement Format

If (the independent variable) is (describe how you change it), the (dependent variable) will (describe the effect).

If __ is __, then ___ will ___.

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 constants

Constant- 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.

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

Types of Graphs Line Graph: usually used to show

changes over time, or data that changes

Bar Graphs: used when comparing data for several different individual items or events.

Pie Chart: used when comparing parts of a whole

Graphing Data…..

Remember: independent

variable should be graphed on the x-axis

dependent variable on the y-axis.

y

x

Drawing Conclusions….

Paragraph format: Restatement of Hypothesis Claim: based on data Evidence: site specific data Reason statement: give reason

for claim Formal writing format based on

fact. Not opinion based No personal Pronouns

SI System Based on the metric system

Units of 10 International use by scientist to communicate

data. 7 Base Units

Length meter m Mass kilogram kg Time second s Temperature kelvin K Electric Current ampere A Amount of a substance mole mol Luminous intensity candela cd

Derived Units

Combinations of the base units: Examples: speed,

density, weight, force, area, volume

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

Common Metric Prefixes

Memorize the basics and their power of 10 Milli 0.001 m Centi 0.01 c Deci 0.1 d Base1.0 Base Unit (Meter, Liter, Gram) Deka 10 dK Hecto 100 h

Kilo 1000 K

Multiplier

Prefix Symbol Numerical Exponential

Yotta Y 1,000,000,000,000,000,000,000,000 1024 zetta Z 1,000,000,000,000,000,000,000 1021 exa E 1,000,000,000,000,000,000 1018 pta P 1,000,000,000,000,000 1015 tera T 1,000,000,000,000 1012 giga G 1,000,000,000 109 Mega M 1,000,000 106 kilo k 1,000 103 hecto h 100 102 deca da 10 101

no prefix means: 1 100

deci d 0.1 10¯1 centi c 0.01 10¯2 milli m 0.001 10¯3 micro µ 0.000001 10¯6 nano n 0.000000001 10¯9 pico p 0.000000000001 10¯12 femto f 0.000000000000001 10¯15 atto a 0.000000000000000001 10¯18 zepto z 0.000000000000000000001 10¯21 yocto y 0.000000000000000000000001 10¯24

Common Measurements Length: The straight-line distance

between two points Mass: a measure of the amount of

matter in an object Volume: a measure of the space an

object takes up or the capacity of a container

Weight: the force that gravity pulls on a quantity of matter.

Temperature Celsius to Kelvin Conversions:

Kelvin = C + 273

Celsius and FahrenheitC = 5/9(F-32)F = (9/5C) + 32

Dimensional Analysis and Conversions If you are converting to a smaller unit,

multiply. If you are converting to a larger unit,

divide.

100cm 1.85m x ---------- = 185 cm 1m

Keys For Success With Dimensional Analysis

Must Use Correct Conversion Factor ** know the prefixes and what they

stand for Don’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.

Conversion Factors of One

1 cm3 = 1ml of space

1g of water takes up 1ml of space or 1 cm3

Scientific Notation

Scientific Notation: a value written as a simple number multiplied by a power of 10.

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)

Examples of Scientific Notation

0.00048 cm = 4.8 x 10-4cm

35,000,000 mm = 3.5 x 107mm

Calculators and Scientific Notation

E values Example: 3.12 x 104

3.12E4 The E value is the exponent power of

10.

Significant Figures Significant 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: 3.25 = 3.2

Sig Fig Rules

Only keep the number of digits in a number that are known to be accurate

When doing math, the answer can not be more precise that the least precise measurement used in the calculation.

Sig Fig’s: Why????

Precise measurement can be important! Historical Perspective: Hubble

Telescope Save time and computations of

needless numbers Why multiply 1.3485676879m when

the measurement is only accurate to 1.34m?

Instrument Precision

Triple Beam Balance = 0.1g Measure of Mass

Meter Stick = 1mm Length

Time = 0.01 s Second

Graduated Cylinder = 0.1mL to 1mL depending on size used. Volume

Can also be solid volume = 0.001m or 1mm Thermometer = 1C

SI Rules All measurements must have a unit

of measure attached to the end. Zero’s mean something!

No naked decimals Put a zero in front 0.5cm

Zeroes at the end indicate the accuracy of the measurement

5.6 is less precise than 5.600 but only put the 00’s if measurement is that precise.