1. Measurement Discuss meaning of the following with a partner: Accuracy
Precision
Keystones: 3.2.b Physics
Objective(s)/SWBAT (Students will be able to):
Define accuracy and precision
Count significant figures and significant digits
Perform operations with sig figs.
Activities:
Determine the perimeter and area of a desk.
Closure:
Practice problems from the text.
Keystones: 3.2.B

2. Measurement
Accuracy – Freedom from mistake or error: correctness. Or, degree of conformity of a measure to a standard.
Precision – The degree of refinement with which an operation is performed or a measurement stated.
Keystones: 3.2.B 2

3. Students will be able to:
Determine uncertainty and % uncertainty
Discuss precision and accuracy in measurement.
State significant figure rules.
Keystones: 3.2.B

4. Measurement: Measure the length and width of your desk.
Keystones: 3.2.B

5. Sig Fig rules for zero’s
Zero’s to the right of significant figures are significant.

6. Sig Fig rules for zero’s
Zero’s between other significant figures are significant.

7. Sig Fig rules for zero’s
Zero’s to the left are place holders and are NOT significant.
Keystones: 3.2.B

8. Let’s try some examples
How many sig figs in each?
0.06 g g
100 g
205 g
2020 cm
620 cm
0.101 cm
3.020 cm 1 3 4

9. Operations with Sig Figs
Addition and subtraction – Keep the least number of significant digits (decimal places).
Multiplication and division – Keep the least number of significant figures.
Demonstrate +/- with mass measurement or perimeter
Demonstrate x/÷ with volume of cylinder and time
Keystones: 3.2.B

10. Try these at our seats 9.3 cm x 17.62 cm x 18 cm 5.62 m x 1.7 m
853.2 g/ cm3
423.4 g – g
43.45 cm – cm
243.1mi – 8.25 mi
2900 cm3 ??? 9.6 m g/cm g 2.20 cm mi

11. Uncertainty Implied and explicit uncertainty. %uncertainty
+- 1 foot, good or bad. Distance to Florida, length of table.
Determine the uncertainty and %uncertainty in the length of the table and the area of a table.
Keystones: 3.2.B