1 2 measurements and uncertainties
Download
Skip this Video
Download Presentation
1.2 Measurements and Uncertainties

Loading in 2 Seconds...

play fullscreen
1 / 36

1.2 Measurements and Uncertainties - PowerPoint PPT Presentation


  • 78 Views
  • Uploaded on

1.2 Measurements and Uncertainties. 1.2.1 State the fundamental units in the SI system. In science, numbers aren ’t just numbers. They need a unit. We use standards for this unit. A standard is: a basis for comparison a reference point against which other things can be evaluated

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' 1.2 Measurements and Uncertainties' - august


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
1 2 1 state the fundamental units in the si system
1.2.1 State the fundamental units in the SI system
  • In science, numbers aren’t just numbers.
  • They need a unit. We use standards for this unit.
  • A standard is:
    • a basis for comparison
    • a reference point against which other things can be evaluated
  • Ex. Meter, second, degree
1 2 1 state the fundamental units in the si system1
1.2.1 State the fundamental units in the SI system
  • The unit of a #, tells us what standard to use.
  • Two most common system:
    • English system
    • Metric system
  • The science world agreed to use the International System (SI)
    • Based upon the metric system.
units and standards

Ex. Length.

  • Base unit is meter.

Units and Standards

common conversions
Common conversions
  • 2.54 cm = 1 in 4 qt = 1 gallon
  • 5280 ft = 1 mile 4 cups = 48 tsp
  • 2000 lb = 1 ton
  • 1 kg = 2.205 lb
  • 1 lb = 453.6 g
  • 1 lb = 16 oz
  • 1 L = 1.06 qt
1 2 2 distinguish between fundamental and derived units and give examples of derived units
1.2.2 Distinguish between fundamental and derived units and give examples of derived units.
  • Some derived units don’t have any special names
1 2 2 distinguish between fundamental and derived units and give examples of derived units1
1.2.2 Distinguish between fundamental and derived units and give examples of derived units.
  • Others have special names
1 2 2 distinguish between fundamental and derived units and give examples of derived units2
1.2.2 Distinguish between fundamental and derived units and give examples of derived units.
  • A derived unit is a unit which can be defined in terms of two or more fundamental units.
  • For example speed(m/s) is a unit which has been derived from the fundamental units for distance(m) and time(s)
scientific notation1
Scientific Notation
  • A short-hand way of writing large numbers without writing all of the zeros.
scientific notation consists of two parts
Scientific notation consists of two parts:
  • A number between 1 and 10
  • A power of 10

N x 10x

step 1
Step 1
  • Move the decimal to the left
  • Leave only one number in front of decimal

93,000,000 = 9.3000000

step 2
Step 2
  • Write the number without zeros

93,000,000 = 9.3

step 3

7

93,000,000 = 9.3 x 10

Step 3
  • Count how many places you moved decimal
  • Make that your power of ten
slide18

The power of

ten is 7 because

the decimal

moved 7 places.

7

93,000,000 = 9.3 x 10

slide19
93,000,000 --- Standard Form
  • 9.3 x 107 --- Scientific Notation
practice problem

9.85 x 107

----->

6.41 x 1010

----->

2.79 x 108

----->

4.2 x 106

----->

Practice Problem

Write in scientific notation.

Decide the power of ten.

  • 98,500,000 = 9.85 x 10?
  • 64,100,000,000 = 6.41 x 10?
  • 279,000,000 = 2.79 x 10?
  • 4,200,000 = 4.2 x 10?
more practice problems
More Practice Problems

On these, decide where the decimal will be moved.

  • 734,000,000 = ______ x 108
  • 870,000,000,000 = ______x 1011
  • 90,000,000,000 = _____ x 1010

Answers

3) 9 x 1010

  • 7.34 x 108

2)8.7 x 1011

complete practice problems
Complete Practice Problems

Write in scientific notation.

  • 50,000
  • 7,200,000
  • 802,000,000,000

Answers

1) 5 x 104

2) 7.2 x 106

3) 8.02 x 1011

scientific notation to standard form

3.40000 --- move the decimal

--->

Scientific Notation to Standard Form

Move the decimal to the right

  • 3.4 x 105 in scientific notation
  • 340,000 in standard form
practice write in standard form
6.27 x 106

9.01 x 104

6,270,000

90,100

Practice:Write in Standard Form

Move the decimal to the right.

accuracy precision
Accuracy & Precision
  • Accuracy:     
    • How close a measurement is to the true value of the quantity that was measured.
    • Think: How close to the real value is it?
accuracy precision1
Accuracy & Precision
  • Precision:    
    • How closely two or more measurements of the same quantity agree with one another.
    • Think: Can the measurement be consistently reproduced?
significant figures
Significant Figures
  • The numbers reported in a measurement are limited by the measuring tool 
  • Significant figures in a measurement include the known digits plus one estimated digit
three basic rules
Three Basic Rules
  • Non-zero digits are always significant.
    • 523.7 has ____ significant figures
  • Any zeros between two significant digits are significant.
    • 23.07 has ____ significant figures
  • A final zero or trailing zeros if it has a decimal, ONLY, are significant.
    • 3.200 has ____ significant figures
    • 200 has ____ significant figures
practice
Practice
  • How many sig. fig’s do the following numbers have?
    • 38.15 cm _________
    • 5.6 ft ____________
    • 2001 min ________
    • 50.8 mm _________
    • 25,000 in ________
    • 200. yr __________
    • 0.008 mm ________
    • 0.0156 oz ________
exact numbers
Exact Numbers
  • Can be thought of as having an infinite number of significant figures
  • An exact number won’t limit the math.
    • 1. 12 items in a dozen
    • 2. 12 inches in a foot
    • 3. 60 seconds in a minute
adding and subtracting
Adding and Subtracting 
  • The answer has the same number of decimal places as the measurement with the fewest decimal places.   

25.2 one decimal place

+ 1.34 two decimal places

26.54  answer

26.5 one decimal place

practice adding and subtracting
Practice:Adding and Subtracting 
  • In each calculation, round the answer to the correct number of significant figures.
  • A. 235.05 + 19.6 + 2.1 =          

1) 256.75  2) 256.8  3) 257    

  • B. 58.925 - 18.2 =          

1) 40.725  2) 40.73  3) 40.7 
 

multiplying and dividing
Multiplying and Dividing
  • Round to so that you have the same number of significant figures as the measurement with the fewest significant figures.

42 two sig figs

x 10.8 three sig figs

453.6  answer

450 two sig figs

practice multiplying and dividing
Practice:Multiplying and Dividing 
  • In each calculation, round the answer to the correct number of significant figures.
  • A. 2.19 X 4.2 =

1) 9    2) 9.2   3) 9.198 

  • B. 4.311 ÷ 0.07 =          

1) 61.58    2) 62   3) 60

practice work
Practice work
  • How many sig figs are in each number listed?
    • A) 10.47020 D) 0.060
    • B) 1.4030 E) 90210
    • C) 1000 F) 0.03020
  • Calculate, giving the answer with the correct number of sig figs.
    • 12.6 x 0.53
    • (12.6 x 0.53) – 4.59
    • (25.36 – 4.1) ÷ 2.317
ad