1. Create placemat and answer the question:
Drill
Create placemat and answer the question:
How many mm are in 3.45dm?
Take out Metric Mania HW
Take out Book Form

2. Check for Understanding
Complete half sheet and put it in the bin
You can use your note sheet! 

3. Agenda Drill Check for Understanding Create book
Accuracy Vs. Precision
Sig Fig Rules
Bag of Lies
HW 
Exit Slip

4. Objectives Evaluate if lab data is precise, accurate, neither, or both
Determine the 4 rules of significant figures (sig figs) with your group
Apply the 4 rules of sig figs accurately
Comprehend the importance of using sig figs for future application of use

5. Warm-Up
I am weighing a rock that I just found on two different scales. When I weigh the rock on a scale found at Dulaney, I find that the rock is 82g. When I weigh the rock on an expensive NASA laser scale, the rock weighs g.
Does it matter how I record this data? Why or why not?

6. Accuracy vs. Precision

7. 1 What does the bulls-eye below show? Accuracy Precision Both Neither

8. 2 What does the bulls-eye below show? Accuracy Precision Both Neither

9. 3 What does the bulls-eye below show? Accuracy Precision Both Neither

10. 4 What does the bulls-eye below show? Accuracy Precision Both Neither

11. Accuracy Definition
The closeness of a measurement to its actual value

12. Reproducibility Repeatability Precision Definition
The degree to which measurements show the same or similar results
Reproducibility
Repeatability

13. 5 Which team was most precise for the two trials?
g/cm3
Team 1
Team 2
Team 3
Team 4
Team 5
Team 6
Trial 1
2.75
2.80
2.70
2.71
2.68
Trial 2
2.76
2.73
2.69
2.65
TEAM 6 = SAME DATA IN BOTH TRIALS
The density of aluminum is known to be 2.70 g/cm3

14. 6 Which team was most accurate for the two trials?
g/cm3
Team 1
Team 2
Team 3
Team 4
Team 5
Team 6
Trial 1
2.75
2.80
2.70
2.71
2.68
Trial 2
2.76
2.73
2.69
2.65
TEAM 4 = AVG 2.70
The density of aluminum is known to be 2.70 g/cm3

15. How Can We Increase Precision in the Lab?
Be honest when reporting a measurement, so that it does not appear to be more accurate than the equipment used to make the measurement allows. We can achieve this by controlling the number of digits, or significant figures, used to report the measurement.

16. Significant Figure Definition
Shorthand way to express how certain one is about one’s data and calculations coming from the data

18. Rules for Significant Figures

19. How many digits are significant?
# of Sig Figs
3 2 5

20. Rule #1
All digits 1-9 are significant

21. Examples:
Number
Number of Sig Figs
459 3
2.1 2
.87992 5

22. How many digits are significant
# of Sig Figs
3 5

23. Rule #2
Zeros in between 1-9 digits are significant

24. Examples
Number
Number of Sig Figs
104 3
1.0402 5
10.508
10001

25. How many digits are significant?
# of Sig Figs
4 1 3

26. Rule #3
Trailing zeros are significant when there is a decimal point

27. Examples
Numbers
Number of Sig Figs
1.800 4
8.060
100 1
100. 3
100.0

28. How many digits are significant?
# of Sig Figs
2 4 3

29. Rule #4
Place holding zeros are NOT significant

30. Examples
Number
How many Sig Figs
0.0090 2 4
0.470 3

31. Rule #4 Continued Scientific Notation 2.40 x 104 - 3 sig figs
The significant digits are the ones before the “x” sign

32. Bag of Lies There are 20 strips of paper in a bag Goal
Determine which strips tell the truth with the correct amount of sig figs and which ones are lies
If you are done early, you will be provided with additional questions to answer in your group.
There can be more than one rule for the reasoning

33. Bag of Lies Example
Truth or Lie?
Why?
If lie, how many sig figs?

34. Challenge: Write your own number
Working in pairs with your group, you will be given specific criteria to write a number with an allotted amount of sig figs.
You will write the number and then will share with the other group.
Groups of 3 will switch from single person to double

35. Example of Challenge
Write a number that is greater than 100 that has 2 significant figures.
Examples include:
120
790
580

36. Challenge questions
Give a number between -1 and 1 that has 5 sig figs.
Give a number greater than 1,000 that has 2 sig figs.
Give a number that is 4 digits but only has 3 sig figs.
Give a number less than 1 that has 3 digits, but only 1 sig fig.
Give a number that is between 5 and 9 that has 4 sig figs.

37. HW Watch the sig fig math and measurement video
Next Class: Metric Olympics and Measurement

38. Exit Slip Please complete exit slip What I am collecting Exit Slip
Place in the bins! 

39. Looking Forward Monday Tuesday Wednesday Thursday Friday 29
Measuring in the lab 2 3
Density 4 5
Percent Error 6 9
Review 10 11
Unit 1 Test 12 13