Quantitative vs. Qualitative - PowerPoint PPT Presentation

Loading...

PPT – Quantitative vs. Qualitative PowerPoint presentation | free to download - id: 6e7cdc-OWNjY



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Quantitative vs. Qualitative

Description:

Quantitative vs. Qualitative Make a quantitative observation about your textbook Make a qualitative observation about your textbook ... – PowerPoint PPT presentation

Number of Views:16
Avg rating:3.0/5.0
Date added: 15 July 2019
Slides: 59
Provided by: yola215
Learn more at: http://www.shucksciencenotebook.yolasite.com
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Quantitative vs. Qualitative


1
Quantitative vs. Qualitative
  • Make a quantitative observation about your
    textbook
  • Make a qualitative observation about your textbook

2
Quantitative vs. Qualitative
  • Quantitative observation
  • Qualitative observation

3
Precision vs. Accuracy
  • Archery Activity

4
Precision vs. Accuracy
  • Which is more precise for measuring volume, a
    beaker or a graduated cylinder?

5
Precision vs. Accuracy
  • Accuracy refers to the closeness of
    measurements to the correct or accepted value of
    the quantity measured.
  • Precision refers to the closeness of a set of
    measurements of the same quantitiy made in the
    same way.

6
Precision vs. Accuracy
  • Measured values that are accurate are close to
    the accepted value
  • Measured values that are precise are close to one
    another but not necessarily close to the accepted
    value

7
Darts within small area High precision
Area covered on bulls-eye High accuracy
8
Darts within small area High precision
Area far from bulls-eye Low accuracy
9
Darts within large area Low precision
Area far from bulls-eye Low accuracy
10
Darts within large area Low precision
Area centered around bulls-eye High accuracy
(on average)
11
Unit conversions
  • Copy metric conversion from book

12
Unit Conversions
  • Practice problems
  • 750 km __________m?
  • 283 m __________km
  • 112 Mwatt __________Kwatt?
  • 112 Mwatt __________Gwatt

13
Scientific Notation Significant Figures
14
Unit Estimation
15
Scientific Notation
  • Used to make numbers more usable
  • 1,000,000,000 1x109
  • 0.00000000011x10-10

16
How do you figure this out?
  • You move the decimal until you have only one
    digit in front of the decimal.
  • If you move right, then the exponent will be
    NEGATIVE based on the number of places your
    decimal moved.
  • If you move left, then the exponent will be
    POSITIVE based on the number of places your
    decimal moved.

17
Practice
  • Give the following in scientific notation
  • 6,289,030,987
  • 0.004500678
  • 5.60987
  • 568.2365400
  • 35.98340002
  • 0.23476

18
Give the following inscientific notation
  • Practice
  • 6,289,030,987
  • 0.004500678
  • 5.60987
  • 568.2365400
  • 35.98340002
  • 0.23476
  • 6.289030987x109
  • 4.500678x10-3
  • 5.60987
  • 5.682365400x102
  • 3.59834002x10
  • 2.3476x10-1

19
Going the other way
  • 1.3487x105
  • 4.9800456x104
  • 2.345x101
  • 5.6789x10-3
  • 3.591x10-1
  • 2.0080x10-2
  • 134,870
  • 49,800.456
  • 23.45
  • 0.0056789
  • 0.3591
  • 0.020080

20
Try For Yourself
  • 7.234x10-5?
  • 8.234x103?
  • 5.000x10-4?
  • 9.99998x10-2?
  • 8.555x106?

21
ANSWERS
7.234x10-5 0.000 072 34 8.234x103
8,234 5.000x10-4 0.000 500 0 9.99998x10-2
0.099 999 8 8.555x106 8,555,000
22
Significant Digits - What is it?
  • When we take measurements in science, we can only
    be sure of our numbers to a certain point
  • The numbers we are sure of are called significant
    digits or significant figures (sig figs)

23
Sig Figs - How do we use them?
  • Two types
  • Measured
  • You actually measure and record your answer to a
    certain digit
  • Calculated
  • You use already measured numbers to compute an
    answer

24
Measured Sig Figs
  • Questions you can answer
  • How long is your book?
  • Measure it with a meterstick and read the length.
  • What is the mass of an orange?
  • Put it on a scale and read the mass.
  • How much milk is in the carton?
  • Pour the milk into a graduated cylinder and read
    the volume.

25
Calculated Sig Figs
  • Sometimes, youve collected the data and you need
    to calculate a final answer
  • Example - you find the length, width and height
    of your book and you want to find the volume.
  • You need to multiply the three numbers together
    to get an answer.

26
Determining what countsSig Fig Rules!
  • All non-zero numbers are significant
  • Example 1,2,3,,9
  • All zeros between non-zero numbers are
    significant
  • Example 1080.305
  • All zeros before a written decimal are
    significant
  • Example 600.

27
More Rules
  • All zeros following non-zero numbers, after a
    decimal are significant
  • Example 1.00 0.003470030
  • These rules are to determine what counts when you
    are looking at a number.

28
Practice
  • How many sig figs are in the following numbers?
  • 2.341
  • 0.0004580
  • 560
  • 560.
  • 560.0003

29
Answers
  • 2.341 has 4 sig figs
  • All the numbers are non-zero digits, so they all
    count!

30
Answers
  • 0.0004580 has 4 sig figs
  • The three non-zero numbers 458 and the zero
    following this set
  • The first four zeros are place holders - they get
    the 4 into ten thousands place

31
Answers
  • Another way to think about 0.0004580 having four
    sig figs is to write it in scientific notation
  • 0.00045804.580x10-4
  • When you write in scientific notation, you only
    write the sig figs before you write the
    x10whatever
  • So here you see that you wrote the 4, 5, 8, and
    0. Those are the sig figs!

32
Answers
  • 560 has 2 sig figs
  • This one is tricky. Notice that there is no
    decimal, so the zero is just a place holder to
    get the 6 into the tens spot.

33
Answers
  • 560. Has 3 sig figs.
  • This time the zero counts because the decimal
    means it was actually measured.

34
Answers
  • 560.0003 has 7 sig figs
  • All zeros are between non-zero digits, so they
    are all significant.

35
How do you know when to stop?
  • When youre measuring, you know when to stop
    based on your equipment.
  • If your equipment reads to the tens, then you can
    guess up to one more place. You can read to the
    ones
  • Lets look at it.

36
Multi step calculations
  • Keep One Extra Digit in Intermediate Answers
  • When doing multi-step calculations, keep at least
    one more significant digit in intermediate
    results than needed in your final answer.
  • For instance, if a final answer requires two
    significant digits, then carry at least three
    significant digits in calculations. If you
    round-off all your intermediate answers to only
    two digits, you are discarding the information
    contained in the third digit, and as a result the
    second digit in your final answer might be
    incorrect. (This phenomenon is known as
    "round-off error.")

37
2 Greatest Sins in Sig Figs
  • Writing more digits in an answer (intermediate or
    final) than justified by the number of digits in
    the data.
  • Rounding-off, say, to two digits in an
    intermediate answer, and then writing three
    digits in the final answer.

38
Reading the right number of digits.
  • Ruler/Meterstick
  • Graduated Cylinder
  • Beaker
  • Scale

39
Calculations - The rules!!!
  • Addition/Subtraction
  • Your answer should have the same number of
    decimal places as the number with the least
    number of decimal places
  • Multiplication/Division
  • Your answer should have the same number of sig
    figs as the number with the least number of sig
    figs
  • Always follow the order of operations!

40
Practice
  • 2.786 3.5
  • 0.0004 x 3001
  • 65 45.32 x 90
  • 45.6 - 34.23
  • 900.3/30.2450

41
Percent Error
  • Percent error determines how accurate an
    experimental value is compared quantitatively
    with the correct or accepted value.
  • Percent error calculated by subtracting the
    experimental value from the accepted value,
    dividing the difference by the accepted value,
    and then multiplying by 100

42
Percent Error
  • Percent error Valueaccepted Valueexperimental
    x 100
  • Valueaccepted
  • Percent error can have a positive or negative
    value

43
Percent Error
  • A student measures the mass and volume of a
    substance and calculates its density as 1.40
    g/mL. The correct, or accepted value of the
    density is 1.36 g/mL. What is the percent error
    of the students measurement?
  • 1.36g/mL 1.40 g/mL x 100 -2.9
  • 1.36 g/mL

44
Percent Error
  • What is your percent error from the lab when you
    found the density of water?
  • 1.00g/mL g/mL x 100 -2.9
  • 1.00 g/mL

Your experimental value
45
Percent Error pg. 45
  • Two technicians independently measure the density
    of a new substance.
  • Technician A Records 2.000, 1.999, 2.001 g/mL
  • Technician B Records 2.5, 2.9, and 2.7 g/mL
  • The correct value is found to be 2.701 g/mL.
  • Which Technician is more precise? Which is more
    accurate?

B
A
46
Go Through Answers on Packet
47
Directly Proportional
  • Two quantities are directly proportional if
  • Dividing one by the other gives a constant value
  • y/x k
  • k constant
  • You can rearrange above equation by saying y
    kx
  • If one increasesthe other increases at the same
    rate (doubling one constant doubles the othr
  • 2y/2x k (constant)

48
Directly Proportional
All directly proportional relationships produce
linear graphs that pass through the origin
49
Inverse Proportions
  • Two quantities are inversely proportional if
  • Their product is constant
  • xy k
  • k constant
  • The greater the speed less time to travel a
    given distance
  • Double speed (2x) ½ required time
  • Halving the speed (½) 2 times the time

50
Inverse Proportional
51
How Sweet It IsChemistry Lab
52
How Sweet It Is Lab
  • Benedicts Solution Water Bath Test
  • Results
  • Beverages should have tested positive if they had
    a sugar sweetener
  • Beverages should test negative if they had an
    artificial sweetener

53
How Sweet It Is Lab
  • What beverages tested positive?
  • What beverages tested negative?
  • Evaluate against labels on Sodas

54
How Sweet It Is Lab
  • What did you notice about the densities of the
    solutions?
  • Which ones had artificial sweeteners? Densities
    less than one?
  • Which ones had natural sugar sweeteners?
    Densities more than one?

55
How Sweet It Is Lab
  • Analysis Questions
  • 1. Evaluate the results against the labels on
    the soda? Record actual sweeteners on a table in
    your lab write-up.
  • How accurate were your results?

56
How Sweet It Is Lab
  • Analysis Questions
  • 2. Which sample do you think had the
    highest/lowest sugar content? Explain why you
    think this.

57
How Sweet It Is Lab
  • Application Questions
  • 1. How could you prove that carbonated water
    contains no sweetener?

58
How Sweet It Is Lab
  • Application Questions
  • How could you determine a regular/diet soda by
    using density and not opening the can?
  • Immerse in waterwhich one will sinkwhich one
    will float?
About PowerShow.com