1. Chapter 1: The Nature of Science
1.1 : The Methods of Science
1.2 : Standards of Measurement
1.3 : Communicating with Graphs

2. 1.1 The Methods of Science

3. Science A method for the study of the natural world
A process that uses observation and investigation to gain knowledge about events in nature

4. Categories of Science
Life Science – involves the study of living things
Earth Science – involves the study of Earth and Space
Physical Science – involves the study of matter and energy

5. Scientific Investigation
Investigations can be done many different ways:
Observations – simply looking at/watching an object(s) and recording what is taking place
Experiments – testing the effect of one thing on another

6. Hypothesis not supported
Scientific Method
State the Problem
Gather Information
Form a Hypothesis
Test the Hypothesis
Analyze Data
Draw Conclusions
Hypothesis not supported
Hypothesis supported

7. Scientific Method
An organized set of 6 steps that scientists use to guide their investigations
State the problem – Why/How?
Gather Information – Learn as much as possible about the problem
Some sources of scientific information are not accurate
Form a hypothesis – a possible explanation for a problem using what you know/observe
Test the hypothesis – Observations/Experiments

8. Scientific Method When testing the hypothesis:
Independent variable – the variable “you” change to see how it will effect the dep. variable
Dependent variable – value changes according to changes in other variables.
[Cause and Effect Relationship]
Constant – A factor that does not change
Control – the standard by which the experimental results can be compared
All other variables should be help constant so that 1 variable is tested at a time

9. Scientific Method
Analyze Data – all data gained in the investigation should be recorded, not just the data you like or think is right
This data can be organized into tables and graphs so that it is easier to read
Draw conclusions – Ask yourself if the data that you gained from the study supports or does not support your hypothesis
If your hypothesis is supported, you must repeat your study to further prove that it is supported
If your hypothesis is NOT supported, you may want to go back and reconsider the hypothesis
One should conduct repeated trials to limit random error in measurements

10. Scientific Bias
Bias occurs when what the scientist expects changes how the results are viewed
Findings are supportable when others can do the same experiment and get the same results

11. Models
Models represent an idea, event, or object to better help people understand it
Why create models?
Models are created in cases where objects are
Too large (ex. The solar system)
Too small (ex. Animal cells, the atom)
Too dangerous (ex. Computer models of nuclear explosions)

12. Scientific Theory vs. Scientific Law
A theory can be used to explain a law!

13. Activity Get into groups of four
On a sheet of paper to be turned in, put:
The problem
Information gathered (if applicable)
Form a hypothesis
How you would test your hypothesis (Include dependent/independent variables, constant, control)
How you would analyze the data
Draw a conclusion and decide whether you support your hypothesis or not

14. EXAMPLE
Problem – (Stated as a question) Does the temperature of a room affect the # of dreams you have?
Hypothesis
An educated guess
A possible answer to the problem
My hypothesis: If the room is hot, a subject will have more dreams

15. EXAMPLE 3. Designing an Experiment Control – 74° F
Constants – type of clothing, type of mattress, lighting, same type of meal before bed, etc.
Independent variable - 45° F, 85° F, 95° F
Dependent variable – Number of dreams recorded the next morning, or recording of brain activity

16. EXAMPLE
4. Analyzing the Data Data Table – temperature vs. number of dreams ex. I could then place the information on a graph
Temperature
Number of Dreams
74° F 2
45° F 4
85° F 7
95° F

17. EXAMPLE
5. Draw a conclusion My data supports my hypothesis because the number of dreams increased as the temperature of the room increased Next, I would repeat the experiment several times to see if I get the same results

18. 1.2 Standards of Measurement

19. Units and Standards
Standard – an exact quantity that people agree to use to compare measurements
Ex. Using Feet/Hands to measure distance across the room
A measurement MUST include a number and a unit
English
Metric SI

20. International System of Units (SI)
Le Systeme Internationale d’Unites
SI standards are accepted and understood by scientists around the world
Each type of measurement has a base unit
Ex. Meter is the base unit for length, Liter for volume, Gram for mass, second for time, kelvin for temp.
Based on multiples of 10, prefixes are used with the names for the units to indicate the multiple of 10
ex. kilo – 1,000, so 1 kilometer = 1,000 meters

21. SI Base Units and Common SI Prefixes
Quantity Measured
Unit
Symbol
Length
meter m
Mass
kilogram kg
Time
second s
Electric current
ampere A
Temperature
kelvin K
Amount of substance
mole
mol
Intensity of light
candela cd
Common SI Prefixes
Prefix
Symbol
Multiplying Factor
Kilo- k
1,000
Deci- d
0.1
Centi- c
0.01
Milli- m
0.001
Micro- μ
Nano- n

22. Dimensional Analysis
Sometimes quantities are measured using different units
To convert from one quantity to another conversion factors are used
1,000 mL/1 L = 1
Ex: Convert L to mL
Ex: Convert 3,075 mm to cm
Ex: Convert11 cm to mm
Ex: Convert 1 kg to g

23. Measuring Distance Length – the distance between two points
Choosing a Unit of length – the size of unit depends on what you are measuring
What measurement would you use to measure the length of a pencil?
How about the distance to your house?
By using the correct unit, you avoid large numbers and numbers with many decimal places

24. Measuring Volume V = l x w x h = units3
Volume (solid object) – the amount of space occupied by an object
V = l x w x h = units3
Volume (liquid) – the capacity of the container that holds the amount of liquid
1 mL = 1 cm3 (Easy to measure if you remember this when you use a graduated cylinder)
Ex. Convert 1.5 L to cm3

25. Measuring Matter
Mass – a measurement of the quantity of matter in an object (golf ball vs. ping pong ball)
Density – the mass per unit of volume of a material
Objects may have the same volume such as cylinders of aluminum, wood, or plastic
Even though they occupy the same space, the matter within them is packed differently
Density = Mass/Volume
Derived Unit – a unit obtained by combining different SI units (g/cm3) / an SI unit multiplied by itself (m3)

26. Measuring Time & Temperature
Temperature is a measure of how hot or how cold something is
Celsius – common for measuring temperature
Fahrenheit
Kelvin – the SI unit of temperature
- 0 K is the coldest possible temp (absolute zero)
- Doesn’t use degrees
- Celsius = (F – 32)/1.8
- Kelvin = Celsius + 273

27. 1.3 Communicating with Graphs

28. Graphs A graph is a visual display of information or data Line Graphs
Graphs make it easier to see patterns or trends in experimental data
Line Graphs
Bar Graphs
Circle Graphs

29. Line Graphs
Show any relationship where the dependent variable (y-axis) changes due to a change in the independent variable (x-axis)
Best for showing continuous data
Can you show more than one event on the same graph?
Yes! As long as the relationship between the variables is the same

30. Classroom Temperature (C°)
Line Graphs
Time*
Classroom Temperature (C°) A B C 16 5 17
16.5 10 19 15 20 21
17.5 23 18 25
18.5
*minutes after turning on heat

31. Constructing Line Graphs
Choose a scale with intervals on each axis in equal measurements
Use the x-axis for the independent variable, just long enough to fit data
Use the y-axis for the dependent variable with 2 data points more than is needed
Use the same unit of measurement
May need to show a break in the axis if your data is very large

32. Implications of Graphs
Direct proportion – one variable increases as the other increases OR one variable decreases as the other decreases
Usually a straight line with a positive slope
Shows a direct relationship that changes at a constant rate
What would a greater slope mean?

33. Implications of Graphs
Inverse proportion – the product of two quantities is a constant
EX. V = f λ
Frequency and wavelength are inversely proportional
As one quantity increases, the other decreases

34. Bar Graphs
Bar graphs are useful for comparing information collected by counting
Each bar represents a quantity counted at a particular time
Where should you plot independent and dependent variables?
Points are not connected because the data is not showing how a change in one variable affects the other

35. Bar Graphs

36. Circle Graphs
A circle (pie graph) is used to show how some fixed quantity is broken down into parts
Circle represents the total
Slices represent the parts, usually a percentage of the total

37. Making a Circle Graph Start with the total of what you are analyzing
For each type, divide that amount by the total
Multiply that decimal by 360° to determine the angle
Ex. Total buildings = 72
18 of the buildings use steam
18 ÷ 72 × 360° = 90°
Then, you would measure 90° on the circle to show 25%

38. Technology Technology is NOT the same as science
Technology is the application of scientific discoveries to meet human needs and goals through the development of products and processes
Engineering focuses on these processes by applying science to make products and design processes

39. Technological Design 4 Stages of Technological Design Requirements
Problem identification
Solution design of a process or product
Implementation
Evaluation
Requirements
Cost and time effectiveness
Materials that meet criteria (price, avaiblity, durability, not harmful, etc.)
Benefits must exceed the risks

40. Scientific Investigation vs. Technological Design
Identifies a problem – asks a ?
Identifies a problem or need
Researches related information
Designs an investigation/experiment
Designs a process or product
Conducts the investigation or experiment – repeated trials
Implements the design or the process – repeated testing
Analyzes the results
Evaluates the conclusion – did the results refute or verify the hypothesis
Evaluates the process or product – did it meet the criteria
Communicates the findings
Communicates the product or process

41. Science Labs and Safety Procedures

42. Labs
In science labs, one uses various instruments to conduct investigations
You must be able to identify and know how to use certain instruments
You must always PUT SAFETY FIRST!!!

43. Graduated Cylinder – used to measure the volume of a liquid
Meniscus – the curve at the tip of a liquid in a graduated cylinder
Measurements are read from the BOTTOM center of the meniscus

44. Thermometer – a device that measures temperature

45. Bunsen Burner
Beaker
Erlenmeyer flask
Funnel
Pipette

46. Measurements The last digit recorded is always estimated
The more decimals in the recorded measurement, the greater the precision of the instrument
EX. A 100 mL graduated cylinder marked in 1 mL increments measures exactly to the ones place
A 10 mL graduated cylinder marked in 0.1 mL increments can be read exactly to the tenths place
Which graduated cylinder is more precise?

47. Precision and Accuracy
Precision – a measure of the degree to which measurements made in the same way agree with one another
Accuracy – the degree to which the experimental value agrees with the true or accepted value
It is possible to have high precision with low accuracy if the same error is involved in repeated trails of the experiment

48. Precision and Accuracy

49. Lab Safety Personal Safety – Follow only designated lab procedures
Understand safety symbols
Wear proper clothing/shoes
Wear proper protective equipment (goggles, aprons)
Tie back loose hair
No eating/drinking
Use proper techniques for smelling, etc.

50. Lab Safety Work area safety – Keep work area clear, uncluttered
Turn off burners/hot plates when leaving lab
Know locations and proper use of the fire extinguisher, safety blanket, eyewash station, emergency shower, first aid kit
Disconnect electrical devices
Clean up
Report incidents, spills, etc. to teacher IMMEDIATELY!