Copyright©2000 by Houghton Mifflin Company. All rights reserved. 1 Steps in the Scientific Method 1.Observations  quantitative  qualitative 2.Formulating hypotheses  possible explanation for the observation 3.Performing experiments  gathering new information to decide whether the hypothesis is valid whether the hypothesis is valid

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 2 Figure 1.1 The Fundamental Steps of the Scientific Method

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 3 Figure 1.2 The Various Parts of the Scientific Method

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 4 Outcomes Over the Long-Term Theory (Model)  A set of tested hypotheses that give an overall explanation of some natural phenomenon. overall explanation of some natural phenomenon. Natural Law  The same observation applies to many different systems different systems  Example - Law of Conservation of Mass

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 5 Law v. Theory A law summarizes what happens; A theory (model) is an attempt to explain why it happens.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 6 Nature of Measurement Measurement - quantitative observation consisting of 2 parts Part 1 - number Part 2 - scale (unit) Part 2 - scale (unit)Examples: 20 grams 6.63    Joule seconds

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 7 International System (le Système International) Based on metric system and units derived from metric system.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 8 The Fundamental SI Units

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 9 Figure 1.3 Measurement of Volume

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 10 Figure 1.4 Common Types of Laboratory Equipment Used to Measure Liquid Volume

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 11 Figure 1.6 Measurement of Volume Using a Buret The volume is read at the bottom of the liquid curve (called the meniscus).

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 12 Uncertainty in Measurement A digit that must be estimated is called uncertain. A measurement always has some degree of uncertainty.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 13 Precision and Accuracy Accuracy refers to the agreement of a particular value with the true value. Precision refers to the degree of agreement among several elements of the same quantity.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 14 Figure 1.7 The Difference between Precision and Accuracy

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 15 Types of Error Random Error (Indeterminate Error) - measurement has an equal probability of being high or low. Systematic Error (Determinate Error) - Occurs in the same direction each time (high or low), often resulting from poor technique.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 16 Rules for Counting Significant Figures - Overview 1.Nonzero integers 2.Zeros  leading zeros  captive zeros  trailing zeros 3.Exact numbers

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 17 Rules for Counting Significant Figures - Details Nonzero integers always count as significant figures has 4 sig figs.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 18 Rules for Counting Significant Figures - DetailsZeros  Leading zeros do not count as significant figures has 3 sig figs.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 19 Rules for Counting Significant Figures - DetailsZeros  Captive zeros always count as  Captive zeros always count as significant figures has 4 sig figs.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 20 Rules for Counting Significant Figures - DetailsZeros  Trailing zeros are significant only  Trailing zeros are significant only if the number contains a decimal point has 4 sig figs.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 21 Rules for Counting Significant Figures - Details Exact numbers have an infinite number of significant figures. 1 inch = 2.54 cm, exactly

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 22 Rules for Significant Figures in Mathematical Operations Multiplication and Division: # sig figs in the result equals the number in the least precise measurement used in the calculation  2.0 =  13 (2 sig figs)

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 23 Rules for Significant Figures in Mathematical Operations Addition and Subtraction: # decimal places in the result equals the number of decimal places in the least precise measurement =  22.5 (3 sig figs)

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 24 Dimensional Analysis Proper use of “unit factors” leads to proper units in your answer.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 25 Temperature Celsius scale =   C Kelvin scale = K Fahrenheit scale =   F

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 26 Figure 1.8 The Three Major Temperature Scales

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 27 Temperature

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 28 Figure 1.9 Normal Body Temperature on the Fahrenheit, Celsius, and Kelvin Scales

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 29 Density Density is the mass of substance per unit volume of the substance:

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 30 Matter: Anything occupying space and having mass.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 31 Classification of Matter Three States of Matter: Solid: rigid - fixed volume and shape Liquid: definite volume but assumes the shape of its container Gas: no fixed volume or shape - assumes the shape of its container

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 32 Types of Mixtures Mixtures have variable composition. A homogeneous mixture is a solution (for example, vinegar) A heterogeneous mixture is, to the naked eye, clearly not uniform (for example, a bottle of ranch dressing)

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 33 Pure Substances Can be isolated by separation methods:  Chromatography  Filtration  Distillation

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 34 Figure 1.10 Simple Laboratory Distillation Apparatus

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 35 Element: A substance that cannot be decomposed into simpler substances by chemical means. Compound: A substance with a constant composition that can be broken down into elements by chemical processes.

Copyright©2000 by Houghton Mifflin Company. All rights reserved. 36 Figure 1.13 The Organization of Matter