1 2 measurements and uncertainties
Download
1 / 36

1.2 Measurements and Uncertainties - PowerPoint PPT Presentation


  • 73 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.



1 2 1 state the fundamental units in the si system3

1.2.1 State the fundamental units in the SI system


Units and standards

Units and Standards


Common conversions
Common conversions on powers of 10

  • 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


Scientific notation
Scientific Notation on powers of 10


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 give examples of derived units.

  • 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: give examples of derived units.

  • A number between 1 and 10

  • A power of 10

    N x 10x


The distance from the sun to the earth
The Distance From the Sun to the Earth give examples of derived units.

149,000,000km


Step 1
Step 1 give examples of derived units.

  • Move the decimal to the left

  • Leave only one number in front of decimal

93,000,000 = 9.3000000


Step 2
Step 2 give examples of derived units.

  • Write the number without zeros

93,000,000 = 9.3


Step 3

7 give examples of derived units.

93,000,000 = 9.3 x 10

Step 3

  • Count how many places you moved decimal

  • Make that your power of ten


The power of give examples of derived units.

ten is 7 because

the decimal

moved 7 places.

7

93,000,000 = 9.3 x 10



Practice problem

9.85 x 10 7

----->

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

--->

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 10 6

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