How Wrong is Wrong??.

Slides:

Advertisements

Similar presentations

Accuracy & Precision Date: ________ (you must have a calculator for today’s lesson)

Advertisements

Significant Digits. Other ways of saying it… Significant Digits Significant Figures Sigfigs Sigdigs.

Errors in Measurements Class measurements for the density of gold (in g/mL) Group 117.8Group Group 218.0Group Group 317.9Group

1. Find your assigned seat and take a seat 2. SURVEY! - Use pencil - DO NOT put your name on it.

Scientific Measurement

To find the density 1- Find the mass of the object 2- Find the volume of the object 3- Divide Density = Mass Volume.

Graphing. a. Circle graph (also called pie chart) Used to show parts of a fixed whole. Usually parts are labeled as percents with the circle representing.

Using and Expressing Measurements

 1. How does quantitative information differ from qualitative information?  2. Convert 75 kilometers to millimeters.

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

Using Scientific Measurements. Uncertainty in Measurements All measurements have uncertainty. 1.Measurements involve estimation by the person making the.

Scientific Notation. Example 1: 1000 Example 2:

Flashback Convert 2.58 m to kilometers. Accuracy and Precision Accuracy- the closeness of measurements to the correct value of the quantity measured.

Analysis The analysis section describes the data and identifies and discusses trends in the data. It is very important to directly use the data to support.

1. Which is more dense, water or wood? How do you know? 2. Which is more dense, 1 pound of lead or 100 pounds of lead? Wood, if it sinks in water. SAME!

Daily Science (Aug) 1. Convert 3.56 m into dm 2. Convert 113 lbs into g (438 g in 1 pound) 1. Convert 1.65 km into inches (1 in = 2.54 cm)

Laboratory Calculations

1 Accuracy and Precision Notes Chemistry 1. 2 Uncertainty in Measurements There is no such thing as a perfect measurement! All measurements have a degree.

Starter Your friend gives you a solid object that is a rectangular solid. Explain how you could determine the density of the material. Your friend gives.

Accuracy vs Precision Accuracy: how close a set of measurements is to the actual value. Precision: how close a set of measurements are to one another.

Error, Accuracy, Deviation, and Precision in Lab data.

Confidence Intervals With z Statistics Introduction Last time we talked about hypothesis testing with the z statistic Just substitute into the formula,

Percent Error How to Calculate it. ERROR!. Error = Measured Value – Accepted Value Science references list the density of aluminum as being 2.7g/cm 3.

Accuracy and Precision. Remember these definitions? ► Accuracy – a description of how close a measurement is to the true value of the quantity measured.

I-Precision: Refers to how close a series of

Introduction to Matter Lecture: Calculating Density.

Acids and Bases Titration of Vinegar

I II III I. Using Measurements (p. 8-15) CH MEASUREMENT.

20 pt 30 pt 40 pt 50 pt 10 pt 20 pt 30 pt 40 pt 50 pt 10 pt 20 pt 30 pt 40 pt 50 pt 10 pt 20 pt 30 pt 40 pt 50 pt 10 pt 20 pt 30 pt 40 pt 50 pt 10 pt Those.

Some guidelines… You will be finding the density of two different substances – one solid and one liquid (DI water). Record the data in a data table You.

Lab 2 Density of a Solid and Liquid Objective - Measure the density of aluminum and water.

DENSITY Density = MASS Volume. MASS –How heavy an object is. –Quantity of matter observed in an object. –Measured in kg, g, or mg –WE FEEL MASS (Atoms).

I II III Using Measurements MEASUREMENT. Accuracy vs. Precision  Accuracy - how close a measurement is to the accepted value  Precision - how close.

Percent Difference Calculations How do experimentally determined values compare to actual values?

Unit 2 MATH OF CHEMISTRY 2.6 Are scientists always 100% correct? AIM: How do we calculate percent error ? DO NOW: Please answer the following question.

Calculations Involving Density Calculating Density from Mass and Volume.

SOL Review 1.  Accuracy: measure of how close a measurement comes to the actual true value  Precision: measure how close a series of measurements are.

I. Using Measurements (p )

Measurements and Mathematics in Chemistry

Density Density: the ratio of the mass of an object to its volume.

Chapter 3: Measurement: Accuracy, Precision, and Error

CH. 1 - MEASUREMENT I. Units of Measurement.

Topic: Math Topics Aim: How do you calculate density & percent error?

Do Now: 3/2/16 HW: Physical/Chemical Changes handout.

Unit 2- Measurements- Accuracy Precision % Error

Thickness of a Thin Layer

Density D= Mass_ Volume Mass: put matter on balance Volume:

آشنايی با اصول و پايه های يک آزمايش

Density Properties Density is a measure of how compact a material is: (please draw picture) Density of most materials will decrease as temperature goes.

Measurement Unit Accuracy vs Precision.

Uncertainty and Significant Figures

Daily Science August 29 Write the abbreviation for microliters.

Accuracy vs. Precision K. Culbertson 2010.

Characteristic physical properties

Sample Size, Margin of Error, and Confidence Intervals

Accuracy vs. Precision.

Accuracy and Precision

Unit 1: Reliability of Measurements

Uncertainty in Measurement

Do Now: 3/9/17 HW: Start Studying! Chemistry 1 Test Fri, 3/17

Accuracy and Precision

Accuracy and Precision

Accuracy and Precision

Accuracy and Precision

Accuracy and Precision

Density What is density?.

Lab Skills Intro.

Presentation transcript:

How Wrong is Wrong??

Percent Error/Percent Deviation My Handy Dandy Reference Table pg 1 % Deviation = ( Difference from accepted Value/Accepted Value) x 100

Sample Problem 1. Working in the laboratory, a student finds the density of a piece of pure aluminum to be 2.85g/cm3. The accepted value for the density of aluminum is 2.699 g/cm3. What is the student's percent error? (0.151/2.699) x 100= 5.6 %

Sample Problem A 75 ml solid is estimated by a student to be 81 ml. Calculate the percent error. (6/75) x 100 = 8.0 %

Error Every measurement made has some error. As technology has advanced we have been able to improve our measurements with tools capable of measuring more precisely.

Keep it under 10 % Lab measurements should be under a 10 % error to be accurate.