1. Intro to Physical Science
Unit 1

2. Science Comes from the Latin word that means “having knowledge”.
Science – a way of learning about the natural world that is based on evidence and logic.

3. How Science Advances
New evidence is usually used to improve earlier ideas rather than entirely replace them.
Different conclusions can be drawn from the same observations, and its not possible to tell which one is correct.
Example: Sun and Earth’s orbit.

4. Theories and Laws
Scientific theory – a broad explanation that is widely accepted because it is supported by a great deal of evidence.
Example: Kinetic theory of matter

5. Theories and Laws
Scientific law – a statement describing what always happens under certain conditions in nature.
It answers “how” questions not “why” questions.
Example: Newton’s Law of Gravity

6. Physical Science Physical Science – the study of matter and energy.
Matter is all the “stuff” that exists in the universe.
Examples: tables, you, air
Energy is what gives matter the ability to move and change.
Examples: electricity, heat, light

7. Physical Science Physical Science can be divided into two areas:
Chemistry – focuses on matter and energy at the scale of atoms and molecules.
Physics – focuses on matter and energy at all scales, from atoms to outer space.

8. Chemistry
Chemistry – the study of the structure, properties, and interactions of matter.
Important concepts:
Physical changes
Water freezing
Chemical reactions
Fireworks exploding

9. Physics
Physics – the study of energy and how it interacts with matter.
Important concepts:
Motion
Forces
magnetism
Forms of energy

10. Scientific Method Scientific Method State the Problem
an organized set of investigation procedures
State the Problem
Form a Hypothesis
Test the Hypothesis
Analyze Data
Draw Conclusions
Communicate Results

11. Scientific Method
Scientists may follow the steps in different sequences, or they may skip or repeat steps.

12. 1.) State the Problem
Observation – any information that is gathered with the senses.
Questions often arise because of an observation.
The question of “why” or “how” is the problem
Example: Does temperature affect the strength of a magnet

13. 2.) Forming a Hypothesis Hypothesis
Educated guess using what you know and what you observe
Must be something that can be tested
Usually “if-then” statements
Example: A magnet is stronger at lower temperatures.

14. 3.) Testing a Hypothesis conduct an experiment make observations
organized procedure for testing a hypothesis; tests the effect of one thing on another under controlled conditions
make observations
build a model to help
represents an idea, event, or object to help people better understand it

15. Variables variable 2 types independent variable/manipulated variable
factor that can cause a change in the results of an experiment
2 types
independent variable/manipulated variable
factor that, as it changes, affects the measure of another variable
The factor that is changed by the researcher
dependent variable/responding variable
factor that changes as a result of changes in the other variables
changes

16. Constants and Controls
a factor that does not change when other variables change
Control
the standard by which the test results can be compared

17. 4.) Analyzing the Data record observations
organizing the data into easy-to-read tables and graphs

18. 5.) Drawing Conclusions
ask the question: Is your hypothesis supported by the analysis of your data?
for the hypothesis to be considered valid, the experiment must result in the exact same data every time it is repeated

19. 6) Communicating results
Researchers should always communicate their results.
Allows other scientists to give feedback and repeat the investigation.
Replication – getting the same results when an experiment is repeated

20. Communicating Results
Write articles for peer-reviewed science journals.
Presentations at scientific meetings.
Creating websites
Writing articles for newspapers and magazines

21. Introduction Measurement is an important science skill.
Other skills needed:
Keeping records
Doing calculations
Organizing data
Making models
Safety

22. Measurement Systems the English system of measurement – United States
The measurement system used by most scientists and most other nations is the metric system
system of measurement based on multiples of ten

23. International System of Units
all SI (system international) standards are universally accepted and understood by scientists throughout the world

24. International System of Units
each type of SI measurement has a base unit and corresponding symbol

25. Measuring Distance length is the distance between two points
Base Unit – meter (m)
Tool – metric ruler and meter sticks

26. the size of the unit you measure with will depend on the size of the object being measured
Example
What unit would you use to measure the classroom width?
Meter
What unit would you use to measure the length of your pencil?
Centimeter

27. Measuring Volume (Liquids)
Base Unit – liter (L)
Tool – graduated cylinder
read at eye level at the meniscus
the curvature of a liquid in a container

28. Measuring Volume (Solids)
the amount of space occupied by an object
Regular Solid
length x width x height
Base Unit – cm3
Tool – ruler
1 mL = 1 cm3

29. Irregular Solid
Water displacement method – using a graduated cylinder with water to determine the volume of a irregular solid
Base unit – liter (L)
Tool – graduated cylinder or overflow can and catch pail

30. Measuring Matter
mass
is a measurement of the quantity of matter in an object.
Base Unit – gram (g)
Tool – balance

31. Measuring Temperature
a measure of the speed of particle movement
greater speed = higher temperature
Basic metric unit - ° Celsius (°C)
Basic SI unit – Kelvin (K)
Tool – Thermometer (liquid in glass)
Celsius
Fahrenheit
Kelvin
b.p. H2O
100°
212°
373
f.p. H2O 0°
32°
273
Absolute zero
-273°
-460°

32. Density
Density
mass to volume ratio of a substance
density is the same for the same material regardless of sample size
can be used to identify a material

33. Density DENSITY = __MASS__ VOLUME D = M V Units  g/mL, g/cm3, g/cc
1 mL = 1 cm3
cc =cubic centimeter, same as cm3
Density of H2O = 1 g/mL

34. Density Problems
A piece of glass has a volume of 75 cm3 and weighs 200 grams. What is its density?

35. A 250 gram weight has a density of 9.2 g/cc. What is its volume?

36. What is the mass of a piece of iron which has a volume of 120 mL and a density of 7.20 g/mL?

37. Metric Conversions
Since metric is based on the number 10 metric conversions are very simple.
Simply move the decimal place to convert from one unit to another.

38. How many jumps does it take?
Ladder Method 1 2 3
KILO 1000 Units
HECTO 100 Units
DEKA 10 Units
DECI 0.1 Unit
Meters Liters Grams
CENTI 0.01 Unit
MILLI Unit
How do you use the “ladder” method?
1st – Determine your starting point.
2nd – Count the “jumps” to your ending point.
3rd – Move the decimal the same number of jumps in the same direction.
4 km = _________ m
Starting Point
Ending Point
How many jumps does it take? 4. 1
__. 2
__. 3
__.
= 4000 m

39. Conversion Practice Try these conversions using the ladder method.
1000 mg = _______ g 1 L = _______ mL 160 cm = _______ mm
14 km = _______ m 109 g = _______ kg 250 m = _______ km
Compare using <, >, or =.
56 cm m 7 g mg

40. Metric Conversion Challenge
Write the correct abbreviation for each metric unit.
1) Kilogram _____ 4) Milliliter _____ 7) Kilometer _____
2) Meter _____ 5) Millimeter _____ 8) Centimeter _____
3) Gram _____ 6) Liter _____ 9) Milligram _____
Try these conversions, using the ladder method.
10) 2000 mg = _______ g 15) 5 L = _______ mL 20) 16 cm = _______ mm
11) 104 km = _______ m 16) 198 g = _______ kg 21) 2500 m = _______ km
12) 480 cm = _____ m 17) 75 mL = _____ L 22) 65 g = _____ mg
13) 5.6 kg = _____ g 18) 50 cm = _____ m 23) 6.3 cm = _____ mm
14) 8 mm = _____ cm 19) 5.6 m = _____ cm 24) 120 mg = _____ g

41. Accuracy and Precison
Measurements should be both accurate and precise.
Accuracy – how close a measurement is to the true value.
Precision – how exact a measurement is.
Neither accurate nor precise
Precise but not accurate
Precise AND accurate

42. Scientific Notation

43. Scientific Notation In science, we deal with some very LARGE numbers:
1 mole =
In science, we deal with some very SMALL numbers:
Mass of an electron = kg

44. Imagine the difficulty of calculating the mass of 1 mole of electrons!kg x
???????????????????????????????????

45. Scientific Notation:
A method of representing very large or very small numbers in the form:
M x 10n
M is a number between 1 and 10
n is an integer

46. . 9 8 7 6 5 4 3 2 1
Step #1: Insert an understood decimal point
Step #2: Decide where the decimal must end
up so that one number is to its left
Step #3: Count how many places you bounce
the decimal point
Step #4: Re-write in the form M x 10n

47. 2.5 x 109
The exponent is the number of places we moved the decimal.

48. 0.0000579 1 2 3 4 5 Step #2: Decide where the decimal must end
up so that one number is to its left
Step #3: Count how many places you bounce
the decimal point
Step #4: Re-write in the form M x 10n

49. 5.79 x 10-5
The exponent is negative because the number we started with was less than 1.

50. Descriptive Statistics
Mean – the average value
Range – the total spread of values

51. Graphs Graphs make it easier to see data.
Three common types of graphs:
Bar graphs – good for comparing values
Circle/pie graphs – good for showing parts of the whole
Line graphs – good for showing changes over time

52. Using Models Model – a representation of an object, system or process.
Example: road map, globe
Help to study things that are too small, large, complex or distant to study directly.

53. Safety Symbols

54. Safety Rules Wear safety goggles. Wear appropriate clothing.
Tie hair back.
Do not eat or drink in lab.
Don’t smell things directly (fan vapors).
Never perform unauthorized experiments.
Wash hand with soap and water before leaving lab.