Section 3-2 Uncertainty in Measurements

Slides:

Advertisements

Similar presentations

Physics Rules for using Significant Figures. Rules for Averaging Trials Determine the average of the trials using a calculator Determine the uncertainty.

Advertisements

Significant Figures. 1.All nonzero digits are significant. Example: 145 (3 sig figs) 2.Zeroes between two significant figures are themselves significant.

Using Scientific Measurements.

Ch. 3.1 – Measurements and Their Uncertainty

Uncertainty in Measurements

Measurements: Every measurement has UNITS.

Uncertainty In Measurement

Precision and Accuracy Uncertainty in Measurements.

How Reliable Are Measurements?

IB Chem I Uncertainty in Measurement Significant Figures.

Using and Expressing Measurements

Chapter 1.5 Uncertainty in Measurement. Exact Numbers Values that are known exactly Numbers obtained from counting The number 1 in conversions Exactly.

Section 2.3 Measurement Reliability. Accuracy Term used with uncertainties Measure of how closely individual measurements agree with the correct or true.

Measurements: Every measurement has UNITS.

The Scientific Method 1. Using and Expressing Measurements Scientific notation is written as a number between 1 and 10 multiplied by 10 raised to a power.

A measured value Number and unit Example 6 ft.. Accuracy How close you measure or hit a true value or target.

How many significant figures?

Measurement book reference p Accuracy  The accuracy of the measurement refers to how close the measured value is to the true or accepted value.

Measurement book reference p Accuracy  The accuracy of the measurement refers to how close the measured value is to the true value.  For example,

Significant Figures (Math Skills) What are they? Why use them? How to use them.

SIG FIGS Section 2-3 Significant Figures Often, precision is limited by the tools available. Significant figures include all known digits plus one estimated.

Reliability of Measurements Chapter 2.3. Objectives  I can define and compare accuracy and precision.  I can calculate percent error to describe the.

Chemistry 3.1 Uncertainty in Measurements. I. Accuracy, Precision, & Error A. Accuracy – how close a measurement comes to the “true value”. 1. Ex: Throwing.

The Importance of measurement Scientific Notation.

Scientific Measurement. Measurements are fundamental to the experimental sciences.  Measurement: A quantity that has both a number and a unit.  Scientific.

Unit 1 Chapter 2. Common SI Units SI System is set-up so it is easy to move from one unit to another.

Do Now: (3 minutes) 1. What are the definitions of precision and accuracy? 2. Why are precision and accuracy important when making measurements?

3.1 Measurement and Uncertainty How do you think scientists ensure measurements are accurate and precise?

Uncertainty in Measurement Accuracy, Precision, Error and Significant Figures.

Uncertainty in Measurement

What is the difference between accuracy and precision? Good precision Low accuracy = average position Low precision High accuracy.

“Scientific Measurement”. Measurements and Their Uncertainty OBJECTIVES: Convert measurements to scientific notation.

Measurement & Calculations Overview of the Scientific Method OBSERVE FORMULATE HYPOTHESIS TEST THEORIZE PUBLISH RESULTS.

Significant Figures. Significant Figure Rules 1) ALL non-zero numbers (1,2,3,4,5,6,7,8,9) are ALWAYS significant. 1) ALL non-zero numbers (1,2,3,4,5,6,7,8,9)

Measurements and their Uncertainty

SIGNIFICANT FIGURES Rules for Significant Figures.

Scientific Measurement. Using and Expressing Measurements Measurement- a quantity that has both number and unit Scientific notation- using exponents to.

Significant Figures All the digits that can be known precisely in a measurement, plus a last estimated digit.

Significant Figures. Rule 1: Nonzero numbers are always significant. Ex.) 72.3 has 3 sig figs.

Significant Figures When we take measurements or make calculations, we do so with a certain precision. This precision is determined by the instrument we.

Chemistry Using and Expressing Measurements Section 3.1.

Chapter 3 Section 2 precision- how close a series of measurements are to one another accuracy- the closeness of measurements to the true value of what.

Chapter 2 Measurements and Calculations Or It all adds up!

Rules for Significant Figures

Significant Figures Notes on PAGE _____. Significant Figures Notes on PAGE _____.

Measurement and Significant Figures

Using Scientific Measurements.

Significant Figures Definition: Measurement with Sig Figs:

Significant Figures.

Warm –up #2 What is chemistry? Write what you recall about the definition and name 2 areas of study of chemistry.

BELLWORK 9/13/16 1 Tm = 1012 m 1mm = 10-3 m 1Mm = 106 m

Aim: Why are Significant Figures Important?

Lecture 5 Significant Figures Ozgur Unal

Active Chemistry Chapter 1 Activity 3

Scientific Measurement Ch. 3

Using Scientific Measurements.

Significant Figures Any digit in a measurement that is known with certainty plus one final digit, which is somewhat uncertain or estimated.

Chapter 3 Scientific Measurement 3.1 Using and Expressing Measurements

Science and Measurement

Uncertainty in Measurement

Measurement book reference p

BELLWORK 9/2/15 How does a scientist reduce the frequency of human error and minimize a lack of accuracy? A. Take repeated measurements B. Use the same.

Chapter 2 Section 3-A.

Scientific Measurement

Section 2.3 Uncertainty in Data

Section 2-3 Using Measurements

Accuracy vs. Precision & Significant Figures

Scientific Measurement Ch. 3

Objectives C-1.1 Apply established rules for significant digits, both in reading a scientific instrument and in calculating a derived quantity from measurement.

2.3 Using Scientific Measurements

Presentation transcript:

Section 3-2 Uncertainty in Measurements

Ideally, measurements are both correct and reproducible. Accuracy – measure of how close a measurement comes to the actual value Precision – measure of how close a series of measurements are to each other.

Error and Percent Error Error = accepted value – experimental value Percent error = error x 100 accepted value

Significant Figures in Measurements Significant figures – measurement includes all the digits that are known plus last digit that is estimated.

Rules – applies to measurements, not counting All nonzeros are significant. Zeros between significants are significant. Placeholders are not significant. Final zeros to the right of the decimal are significant.

Calculation with significant digits Multiplication and Division- -round to number that is least precise number of digits of the numbers used. Addition and Subtraction- -round to least precise decimal place of the numbers added.

How many significant figures in the following measurements? 1. 123 meters 2. 0.123 meters 3. 40506 meters 4. 9.8000 x 104 5. 30.0 meters 6. 0.07080 meters 7. 98000 meters

Round the following to the # of sig figs in ( ). 314.721 meters (4) 0.001775 meter (2) 64.32 x 10-1 (1) 8792 meters (2)

Significant Figures in Multi-step Problems Do not round on intermediate steps but apply significant figure rules to final answer.

Rounding Rules Above 5 - - round up Below 5 -- round down Exactly 5 (such as 2.45 round to 2 significant digits). Number to the left is even-leave it Number to the left is odd-round up Above example = ??? 2.4

Round the following to 3 Significant Figures 2.235 cm 16.251 m 56.55 g 7.145 ml 56.45000001 s