Transcript Manipulating Numerical Data

Chemistry and Manipulating
Numerical Data
Measurements
 science is based
Numbers
 mathematics is
on measurements
based on numbers
 all measurements
have:
- magnitude
- uncertainty
- units
 exact numbers are
obtained by:
- counting
- definition
Graphs
Bar Graph
shows how many of something
are in each category
Chemistry Grades
10
8
6
4
2
0
A
B
C
D
F
Unit 1 Test – Honor’s Chemistry
Introduction to Chemistry
1st Hour
2nd Hour
5th Hour
6th Hour
8th Hour
55 B’s
27 A’s
35 C’s
Avg: 40.9 + 4.0
83.8 + 8.0 %
5 D’s
50
45
40
35
30
This is also about what the quarter grades will look like.
September 14, 2007
Pie Graph
shows how a whole is broken into parts
40%
15%
Percentage of
Weekly Income
Entertainment (40%)
Food (25%)
Clothing (20%)
Savings (15%)
20%
25%
Line Graph
shows continuous change
Stock Price over Time
Share Price ($)
60
50
40
30
20
10
0
Jan
Feb
Mar
Month
Apr
Elements of a “good” line graph
• axes labeled,
with units
• use the
available space
• title
• neat
Volume (L)
Temp. v. Vol. for a Gas at Constant
Pressure
10
9
8
7
6
5
4
3
2
1
0
120
140
160
180
200
Temp. (K)
220
240
How to read a graph
•
•
•
•
Interpolate - read between
data points
What volume would the gas
occupy at a temperature of
150 K? 7 L
Extrapolate - read data
beyond data points
What volume would the gas
occupy at a temperature of
260 K? ~4 L
Which do you have more
confidence in? Why?
Volume (L)
•
(dependent variable)
Temp. v. Vol. for a Gas at Constant
Pressure
10
9
8
7
6
5
4
3
2
1
0
120
140
160
180
200
Temp. (K)
(independent variable)
220
240
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
Number of Students
70
Legend
60
50
A
B
C
D
40
30
20
10
0
1st Qtr
Axis labeled
(with units)
2nd Qtr
3rd Qtr
4th Qtr
Pie Graph
Calcium
3%
Pie Graphs
Iron
5%
Aluminum
8%
Other
9%
Oxygen
49%
Silicon
26%
Earth's Crust
Oxygen
Silicon
Other
Aluminum
Iron
Calcium
Reviewing Concepts
Presenting 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?