1. Measurement Lab 2 Significant Figures Calculations

2. Objectives: Informal Assessment: Formal Assessment:
Use proper technique to make accurate and precise measurements.
Apply the rules for significant figures to calculations.
Informal Assessment:
Monitoring student interactions and questions as they complete the measurement lab and significant figures practice
Formal Assessment:
Analyzing student responses to measurement lab and significant figures practice
Common Core Connection
Use appropriate tools strategically
Attend to precision
Make sense of problem and persevere in solving them

3. Lesson Sequence Evaluate: Warm-Up
Explain: Measuring to the Correct Sig Figs
Elaborate: Measurement Lab Trial 2
Evaluate: Significant Figures Inquiry
Elaborate: Significant Figures Practice
Explain: Significant Figures Calculations
Elaborate: Significant Figures Calculation Practice
Evaluate: Exit Ticket

4. Warm - Up Measure the length of the index card on your desk
What unit did you measure the length in?
How many decimal places did you measure it to?
Why did you measure it to that number of decimal places?

5. Objectives: Today I will be able to:
Use proper technique to make accurate and precise measurements.
Apply the rules for significant figures to calculations.

6. Homework Finish Significant Figures Calculations WS
Study for Significant Figures Quiz on Wednesday, September 3

7. Agenda Warm-Up Measuring to the Correct Sig Figs
Measurement Lab Trial 2
Significant Figures Inquiry Wrap-Up
Significant Figures Practice
Significant Figures Calculations
Significant Figures Calculation Practice
Exit Ticket

8. Draw this table on the back of your measurement lab
Lab Equipment
Unit of Measurement
(cm, g, mL, etc.)
Number of Decimal Places it Can be Read to
Ruler/ Meter Stick
Balance
Beaker
Graduated Cylinder
Erlenmeyer Flask
Complete the table and if you are having trouble look at your trial 1 measurements from yesterday

9. Measurement Lab Trial 2
Travel to the stations in the lab and measure the mass, volume or length to the correct number of decimal places. DON’T Record the number of sig figs in your trial 2 measurement. Record 3 of your measurements on the board

10. Class Discussion
How do the trial 2 measurements differ from the trial 1 measurements?
Why are significant figures important?

11. Take out the Sig Fig Inquiry Worksheet
Wrap-Up of the Sig Fig Rules

12. Significant Figure Notes

13. Atlantic Pacific Rule

14. Atlantic Pacific Rule
If a decimal point is Present as in km, count from the “Pacific Side” from the first nonzero digit to the end. Meaning, count from the left side of the number
52.3 has 3 sig figs
How many sig figs in
There are 5 sig figs (start counting at 9)

15. Atlantic Pacific Rule
If the decimal point is Absent, as in g, count from the Atlantic Side beginning with the first nonzero digit and going to the end, counting any zero as significant. This means start from the right
g has 3 sig figs
How many sig figs in 190,542,100ml
- There are 7 sig figs

16. Examples m
- 5 kg
- 6
25,000,000, 000 mm
- 2
1,908,150 L
- 6
520 ml
- 2
.0102 ns
- 3

17. Sig Fig Calculations
You cannot be more precise than your least precise measurement
In multiplication and division, the measurement with the smallest number of sig digits determines how many digits are allowed in the final answer
If you have several steps, carry the extra digits. Only the final answer is rounded

18. Examples Your answer can only have 3 sig figs 6.15 m x 4.026 m = ?
6.15 m has 3 sig figs
4.026 m has 4 sig figs
Your answer can only have 3 sig figs
m2  24.8 m2

19. Examples .03287 g x 45.2 g = ? 45.2 g has 3 sig figs
Your answer can only have three sig figs
g  1.49 g

20. Final Note
When doing calculations with significant figures, conversion factors do not figure in
Counts and defined numbers are EXACT and have no uncertain digits
Example: if you say there are 6 people in your family it is a counted number and is considered certain. There are not 6.1 people in your family
Example: 12 inches = 1 foot is defined – do not use significant figures. 1 foot will never be inches. In both cases, significant figures do not apply

21. Significant Figures Calculation Practice
Complete the practice at your desk. Problems not completed in class will become your homework.

22. Exit Ticket
Complete the calculation to the correct number of sig figs.
4.21 X =
– 2.2 =
Icebreaker:
If you could turn yourself into something different (car, animal, plant, etc) for one week, what would it be?
Would you rather be 4 inches tall or 100 ft tall?