1. Unit 0 Introduction Chapter 1
Physical Science
Unit 0
Introduction
Chapter 1

2. What is Science
Science is a system of knowledge and the methods you use to find that knowledge.
Science begins with curiosity and often ends with discovery.

3. Science vs. Technology Technology – the application of science.
Science and technology are
interdependent. Advances in one
lead to advances in the other.

4. Branches of Science Chemistry: The study of Matter and its changes
Students to copy down definition of Physics and Chemistry
Chemistry: The study of Matter and its changes
Physics: The study of Forces and Energy

5. How Science is conducted…
Science is an investigation, which starts with observations leading to inferences.
An observation is any information collected with the senses.
An inference is a conclusion or deduction based on observations.

6. Basic steps of Scientific Method
Make an observation
Ask a question
Form a hypothesis
Test hypothesis/Experiment
Analyze data/draw conclusion
Develop theory

7. Scientific Method Steps 1-3
Begins with an observation (I see smoke in the distance)…
…that leads to a question. (what’s causing the smoke)
Form a hypothesis – a possible answer that you can test. (Some one is burning leaves.)

8. Scientific Method Step 4 Conduct an Experiment
A good experiment tests only one variable at a time.
No experiment is a failure.

9. Variables Variable – anything that can change in an experiment.
Independent variable – what you change. (manipulated)
Dependent variable – what changes because of the independent variable. (responding/what is measured)
Control-what you keep the same.

10. Scientific Method Step 5
Analyze data
If data DOESN’T support hypothesis then you need to revise the hypothesis and retest
If data DOES support hypothesis then additional testing is needed before developing a theory
1st period stopped here Wednesday.

11. Scientific Method Step 6
Scientific Theory: Is an explanation that has been tested by repeated observations.
Are always being
questioned and examined.
To be valid, a theory must continue to pass each test.

12. Scientific Theory (cont.)
A theory must explain observations simply and clearly..
Experiments that illustrate the theory must be repeatable.
You must be able to predict from the theory.

13. Scientific Law
Scientific Law: States a repeated observation about nature.
Does not explain why an event happens.

14. Theories and Laws are not absolute.
Sometimes theories or Laws have to be changed or replaced completely when new discoveries are made.

15. Scientific Model Model: is a representation of an object or event.
Scientific models make it easier to understand things that might be too difficult to observe directly.

16. Graphs A way of organizing and presenting data.
Makes relationships more evident.

17. Line graphs
Best for displaying data that changes. (anything over time)
Numerical vs.
Numerical

18. Multiple Line Graphs
Best for comparing multiple values and distributions.

19. Bar Graphs
Best when comparing data for several individual items or events.
Numerical vs. Non-numerical

20. Pie Charts (AKA Circle Graphs)
Best for displaying data that are parts of a whole.

21. Units of Measurement
Scientists use the International System of Units (SI units) for measurements.
When everyone uses the same units, sharing data and results is easier – less mistakes.

22. Base Units The official SI units to measure:
Length = meter (m), is the straight-line distance between two points.
Volume = liter (L), the amount of space taken up by an object.
Mass = gram (g), quantity of matter in an object.
Time = seconds (s)
Temperature = Kelvin (K)

23. Derived Unit Derived units, are made from combinations of base units.
Area: square meter (m2)
Volume: cubic meter (m3)
Density: kilograms per cubic meter (kg/m3) [a measurement of mass/volume]
Pressure: pascal (Pa) [a measurement of force/area]
Energy: Hertz (Hz) [a measurement of force/distance]
Electric charge: coulomb (C) [is a measurement of current /time]

24. Metric Prefixes
Metric prefixes allow for more convenient ways to express SI base and derived units.
Prefix
Kilo
Hecto
Deca
Base
Deci
Centi
Milli
Symbol k h da
--- d c m
meaning
103
102
101
100
10-1
10-2
10-3

25. King Henry - Conversions
Use the sentence “King Henry Died by Drinking Chocolate Milk.” to remember the order of prefixes.
Kilo Hecto Deca base Deci Centi Milli
meter
liter
gram

26. Metric Prefixes
Prefixes attach to the front of metric units and multiply them.
kilo-
1,000 k-
hecta-
100 h-
deca- 10
da-
liter
meter
gram
deci-
1/10 d-
centi-
1/100 c-
milli-
1/1,000 m-

27. SI Prefix Conversions Prefix Symbol Factor mega- M 106 kilo- k 103
deci- d
10-1
centi- c
10-2
move left
move right
milli- m
10-3
micro- μ
10-6
nano- n
10-9
pico- p
10-12

28. Converting Metric Units
Sometimes we have to convert metric units to make them more useful.
Example: The distance from the center of Statesville to the center of Charlotte is about 66,000m meters(m).
Since that distance is thousands of meters, it would be more convenient to use kilometers(km) instead.
How can we change 66,000 m to km?

29. Moving the Decimal In metric conversions, move the decimal.
Look at your prefix line.
k- h- da- b d- c- m-
We’re going from meters (a base unit) to kilometers (k-).
We have to move three places left.
Move the decimal left three places.
66,000 m
66.0 km = 66,000 m

30. Moving the Decimal
If a pencil is 0.14 meters long, how long is it in cm?
Look at the prefix line.
k- h- da- b d- c- m-
Move the decimal right two times.
0.14 m = 14 cm

31. Metric Prefixes How many grams(g) are in one centigram(cg)?
How many meters(m) are in one kilometer(km)?
Answer: kilo- = 1,000, so there are 1,000 meters in a kilometer.
1,000 m = 1 km
How many grams(g) are in one centigram(cg)?
Answer: centi- = 1/100, so there are 1/100 grams in a centigram.
1/100 g = 1 cg

32. King Henry - Conversions
Remembering the prefixes in order is the key to doing ANY metric conversion.
Write the prefixes in order.
Count the number of “JUMPS” between the two prefixes.
If going up the prefixes move the decimal to the left the same number of spaces as “JUMPS”
If going down the prefixes move the decimal to the right the same number of spaces as “JUMPS”
2nd block

33. Practice K h da base d c m Convert 2.45 hm to cm
Going down the prefixes so move the decimal 4 spaces to the right
2.45 hm = cm
Convert 526 mg to g
Going up the prefixes so move the decimal 3 spaces to the left.
526 mg = g

34. K h da base d c m Practice Convert 3.876 Kg to dg
Moves to the right = dg
Convert 526 dL to hL
Moves to the left = hL
Convert 2.8 s to ms
Moves to the right =2800 ms
Convert 45 g to Kg
Moves to the left = Kg

35. Scientific Notation
When writing very large or very small numbers, scientists use a kind of shorthand called scientific notation.
This is a way of writing a number without so many zeros.

36. Examples: The speed of light is about 300,000,000 m/s
Or x 108 m/s
The mass of a proton is
Or X 10-24

37. All you do is move the decimal so that you only have one number before the decimal.
850,000,000.0
= 8.5 x 108
For large numbers the exponent is positive!!

38. For small numbers the exponent is negative!!
All you do is move the decimal so that you only have one number before the decimal.
= 2.5 x 10-8
For small numbers the exponent is negative!!

39. Scientific Notation Examples
= ?
Small number = - exponent x 10-3
= ?
Large number = + exponent x 105
= ?
Small number = - exponent x 10-5
= ?
Large number = + exponent x 105

40. Getting numbers out of Scientific Notation
Look at the exponent of the number to determine if it needs to get smaller or larger.
Positive exponent means the number gets larger so the decimal moves to the right.
Negative exponent means the number gets smaller so the decimal moves to the left.
Add zeros to fill in any “BLANK” spaces.

41. Example 1: x 105
The exponent is positive so the number needs to get larger or
Example 2: x 10-4
The exponent is negative so the number needs to get smaller or

42. Scientific Notation Examples
positive exponent = large number
9.78 x 109
positive exponent = large number
5.24 x 10-3
Negative exponent = small number
2.41 x 10-7
Negative exponent = small number

43. Significant Figures
Significant Figures: are all the digits that are known in a measurement, plus the last digit that is estimated.
The fewer the significant figures, the less precise the measurement.
Precision: is a gauge of how exact a measurement is.
When making calculations using measurements, the number with the least amount of significant figures will determine how many significant figures the calculated value will have.

44. Significant Figures Examples
Density = 34.73g / 𝑐𝑚 3
When we divide these two numbers we get g/ 𝑐𝑚 3
Since the volume ( 𝑐𝑚 3 ) has 3 significant figures and the mass has 4 significant figures, we will only have 3 significant figures in our answer.
So we will round our answer to 7.86 g/ 𝑐𝑚 3
Density = 40.25g / 𝑐𝑚 3
What would our answer be?
3.022 g/ 𝑐𝑚 3

45. Accuracy
Accuracy: is the closeness of a measurement to the actual value of what is being measured.
Example: A clock that is running 15 minutes slow will remain precise to the nearest second, but it will be not be accurate.

46. Derived Units Combination of base units.
Volume = length × length × length
1 cm3 = 1 mL dm3 = 1 L
Density = mass per unit volume (g/cm3)
Density is love <3

47. Density
Density: is the ratio of an objects mass to its volume.
Density of water = 1.0 g/ml
A substance that is more dense than water will sink when placed in water.
A substance that is less dense than water will float in water.
The density of cooking oil is 0.9 g/ml. Would cooking oil sink or float in water?
D = M V

48. Density
cooking oil
water (with food coloring)

50. D M V Density Practice V = 825 cm3 M = DV D = 13.6 g/cm3
An object has a volume of 825 cm3 and a density of 13.6 g/cm3. Find its mass.
GIVEN:
V = 825 cm3
D = 13.6 g/cm3
M = ?
WORK:
M = DV
M = (13.6 g/cm3)(825cm3)
M = 11,220 g D M V

51. D M V Density Practice D = 0.87 g/mL V = M V = ? M = 25 g V = 25 g
A liquid has a density of 0.87 g/mL.
What volume is occupied by 25 g of the liquid?
GIVEN:
D = 0.87 g/mL
V = ?
M = 25 g
WORK:
V = M D D M V
V = g
0.87 g/mL
V = 28.7 mL

52. D M V Density Practice M = 620 g D = M V = 753 cm3 D = ? D = 620 g
2) You have a sample with a mass of 620 g & a volume of 753 cm3. Find density.
GIVEN:
M = 620 g
V = 753 cm3
D = ?
WORK:
D = M V D M V
D = g
753 cm3
D = 0.82 g/cm3

53. Measuring
To measure length, use a metric ruler or a meter stick.
1 cm

54. DO NOT USE!
USE!

55. Measuring
To measure mass, you would use an electronic digital balance or a triple-beam balance.

56. Measuring To measure the volume of a box shape
(1) measure its length, width, and height with a metric ruler, then
(2) multiply the three dimensions.
volume = length x width x height (in cm3)

57. Measuring To measure mass of liquid:
(1) get the mass of the empty beaker,
(2) add the liquid and get the mass of the beaker plus the liquid, and
(3) subtract the mass of the empty beaker.
You will be left with the mass of just the liquid.

58. Measuring To measure the volume of a liquid, use a graduated cylinder.
Read the liquid’s volume from the bottom of the meniscus.
Meniscus = curved surface of liquid in graduated cylinder.
Read volume from here!
Not here!

59. Measuring
To measure the volume of an irregular solid (such as a rock), use water displacement.
Water Displacement Method
- Read the initial volume of water in a graduated cylinder
- Place object into cylinder
- Read the final volume of water
- Final – Initial = Volume of the object
Difference in volumes = volume of rock.

60. The same marble was placed into 5mL of water. What is its density?
A marble with a mass of 3.8 g was placed into 10 mL of water. What is its density?
The same marble was placed into 5mL of water. What is its density?
the volume is equal to the displacement of marble