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Chemistry and Manipulating Numerical Data. Numbers. Measurements. mathematics is based on numbers exact numbers are obtained by: - counting - definition. science is based on measurements all measurements have: - magnitude - uncertainty - units.
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Numbers Measurements • mathematics is based on numbers • exact numbers are obtained by: • - counting • - definition • science is based on measurements • all measurements have: • - magnitude • - uncertainty • - units
Bar Graph shows how many of something are in each category
1st Hour 2nd Hour 5th Hour 6th Hour 8th Hour Unit 1 Test – Honor’s ChemistryIntroduction to Chemistry 55 B’s 27 A’s 35 C’s Avg: 40.9 + 4.0 83.8 + 8.0 % 5 D’s 45 40 35 30 50 This is also about what the quarter grades will look like. September 14, 2007
Percentage of Weekly Income Pie Graph shows how a whole is broken into parts
Line Graph shows continuous change Stock Price over Time
Elements of a “good” line graph • axes labeled, with units • use the available space • title • neat
How to read a graph • Interpolate - read between data points • What volume would the gas occupy at a temperature of 150 K? • Extrapolate - read data beyond data points • What volume would the gas occupy at a temperature of 260 K? • Which do you have more confidence in? Why? 7 L (dependent variable) ~4 L (independent variable)
Graphs • Line Graph • Used to show trends or continuous change • Bar Graph • Used to display information collected by counting • Pie Graph • Used to show how some fixed quantity is broken down into parts
Line Graph How does the mass of a penny change with age? B A Mass (g) Mass (g) Age (Year of Penny) Age (Year of Penny) D C Mass (g) Mass (g) Age (Year of Penny) Age (Year of Penny)
Bar Graph Descriptive title Chemistry Grades Legend Number of Students Axis labeled (with units)
Reviewing ConceptsPresenting Scientific Data • How do scientists organize data? • How can scientists communicate experimental results? • What does a given point represent on a line graph? • The density of copper is 8.92 g/cm3. If you plotted the volume in cubic centimeters, what would the slope of the line be?