1. Data Analysis

2. Bell Ringer – brain teaser
A baseball team had won a game No errors. But not a single man crossed the plate. How could this be?

3. From lab on Friday Accuracy is?
How close your measurement is to the true value
Precision is?
How close several measurements are to one another
When you tossed the bean bag, were you able to hit the bullseye every time?
How about your partners?

4. Review on accuracy vs precision
High or low accuracy?
High or low precision?
Low accuracy; low precision
High accuracy; high precision
Low accuracy; high precision
High accuracy

5. Rounding Numbers Rules:
If digit to right of the last SF is < 5, do not round.
If digit to right of the last SF is > 5, round up.
If digit to right of the last SF is = 5 & followed by a non-zero digit, round up.
If digit to right of the last SF is = 5 but not followed by a non-zero digit, look at the last SF. If it’s an odd digit, round it up. If it’s an even digit, do not round.
but

6. Practice Round 3.5150114 to: A) five significant figures
(Rule 1)
B) three significant figures
3.52 (Rule 4)
C) one significant figure
4 (Rule 3)

7. You practice Page 41 # 33 Round all numbers to four sig. fig.
A) 84,791 kg
84,790 kg
B) g
38.54 g
C) cm
256.8 cm
D) m
4.936 m

8. Graphing
Relationships

9. Why do you think…
Why do you think scientists present their data in graphs?
Write your thoughts in your notebook.

10. Why use graphs? To find relationships in data
To see if a pattern exists that may help analyze data.

11. Circle graphs

12. Circle graphs Pie chart Divided into wedges
Useful for showing parts of a fixed whole
Parts usually labeled as percents (%) with the circle as a whole representing 100%
Looking at the example, how many people like vanilla ice cream?

13. Bar graph

14. Bar graphs
To show how a quantity varies with factors like time, location, temperature, etc…
Quantity measured is on the y-axis (vertical axis)
Independent variable is on the x-axis (horizontal axis)
Examples would include how rain rates change over 30 years in a location.

15. Line graphs

16. Line graphs What you’ll use most in chemistry
The points on a line graph represent the intersection of data for two variables.
The x axis
independent variable (the variable the scientists deliberately change during an experiment)
The y axis
dependent variable (the variable that changes according to the independent variable)

17. Best fit line

18. Best fit line
Because the points are scattered, the line cannot pass through all the data points.
The best fit line is drawn so that about as many points fall above the line as fall below the line.
If the best fit line is straight, there’s a linear relationship between the variables, and they are directly related
Slope :

20. Finding slope

21. Direct Proportion
Two quantities are directly proportional if dividing one by the other gives a constant value.
Density = Mass
Volume

22. Direct Proportion

23. For a fixed amount of gas, Constant = Pressure x Volume
Inverse Proportion
Two quantities are inversely proportional if their product is constant.
For a fixed amount of gas,
Constant = Pressure x Volume

24. Inverse Proportion
graphing y = 1 x
yields a straight line

25. practice
Mercury
Wood
Iron
Lead

26. What needs to be on a graph

27. You make a graph with your partner
Make sure you choose a graph that is appropriate to your data
Make sure you have the following:
Title for your graph
Title for all axes
Units
Proper scale
Data points with connected lines if appropriate

28. What’s on your test Units of measurement Scientific notation Density
Temperature
Dimensional analysis
Accuracy vs precision
Percent error
Significant Figures
Rounding numbers
Graphing
Review tomorrow
Test Thursday