1. Science Process, Graphing, SI System
Unit 1
Science Process, Graphing, SI System

2. 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.

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. 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

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:
Observe
Question
Hypothesis
Test/Experiment
Collect/Analyze Data
Draw 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 measurement
Examples: length, temperature, mass, volume
Inferences: 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 problem
Only asks one thing at a time.
Stated clearly
Looks for a specific outcome.

9. 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.

10. 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).

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 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.

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 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

15. Graphing Data….. Remember:
independent variable should be graphed on the x-axis
dependent variable on the y-axis. y x

16. 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

17. 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

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 10
Milli m
Centi c
Deci 0.1 d
Base 1.0 Base Unit (Meter, Liter, Gram)
Deka 10 dK
Hecto 100 h
Kilo K

21. Prefix Symbol Numerical Exponential
Multiplier
Prefix Symbol Numerical Exponential
Yotta 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 h
deca da
no prefix means:
deci d ¯1
centi c ¯2
milli m ¯3
micro µ ¯6
nano n ¯9
pico p ¯12
femto f ¯15
atto a ¯18
zepto z ¯21
yocto y ¯24

22. 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.

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.
100cm
1.85m x = 185 cm 1m

25. 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.

26. Conversion Factors of One
1 cm3 = 1ml of space
1g of water takes up 1ml of space or 1 cm3

27. Scientific Notation
Scientific 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 10-4cm
35,000,000 mm = 3.5 x 107mm

30. Calculators and Scientific Notation
E values
Example: x 104
3.12E4
The E value is the exponent power of 10.

31. 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: = 3.2

32. 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.

33. Sig Fig’s: Why???? Precise measurement can be important!
Historical Perspective: Hubble Telescope
Save time and computations of needless numbers
Why multiply m when the measurement is only accurate to 1.34m?

34. Instrument Precision Triple Beam Balance = 0.1g Meter Stick = 1mm
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

35. 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 but only put the 00’s if measurement is that precise.