1. Accuracy and Precision
Measurements are qualitative or quantitative.
Qualitative measurements give results that are descriptive and non-numerical.
Example:
Quantitative measurements give results that are definite, usually as numbers and units.

2. Can you hit the bull's-eye?
Three targets with three arrows each to shoot.
How do they compare?
Both accurate and precise
Precise but not accurate
Neither accurate nor precise
Can you define accuracy and precision?

3. a)78.1 mL, 43.9 mL, 2 mL accurate precise should be 100mL both neither
b) 68.1 mL, 68.2 mL, 68.0 mL accurate precise should be 68.1mL both neither
c) 98.0 mL, 98.2 mL, 97.9 mL accurate precise should be 100mL both neither
d) 72.0 mL, 60.3 mL, 68.1 mL accurate precise should be 100mL both neither
BOTH
BOTH
NEITHER

4. Accuracy and Precision
Measurements work best when they are accurate and precise
Accuracy is a measure of how close a measurement comes to the actual or true value of whatever is measured.
To evaluate the accuracy of a measurement, it must be compared to the correct value.
Precision is a measure of how close a series of measurements are to one another.
The precision of a measurement depends on more than one measurement. Repeatability.

5. Accuracy and Precision

6. Accuracy and Precision
DRAW THESE 4 in your
Notebook. Label what each
Indicates.

7. Accuracy and Precision
In this picture, all of the darts land on the bulls-eye which illustrates good precision and accuracy.
In this picture, all of the darts land near each other, but away from the bulls-eye which illustrates good precision, but poor accuracy.

8. Accuracy and Precision
Here the darts are not close to each other, but are close to the bulls-eye indicating poor precision, but good accuracy.
Finally, the darts are not close to each other or near the bulls-eye indicating both poor accuracy and poor precision.

9. Accuracy and Precision
What is the following an example of:
You did an experiment to see at what degree water boiled in Celsius.
You got the following results.
T1- 65
T2- 67
T3 – 66
Accuracy or Precision????
PRECISION

10. Accuracy and Precision
A basketball player throws 100 free-throws; 95 of these balls go through the goal; 5 miss the goal entirely.
Describe the precision and accuracy of the free-throws.
95% accurate and 95% precise

11. The same player is having an off day;
5 balls go through the goal; the other
95 balls bounce off of the rim.
Describe the precision and accuracy
of the throws
5% accurate
95% precise .

12. Each of five students used the same ruler to measure the length of the same pencil. These data resulted: cm, cm, cm, cm, cm. The actual length of the pencil was cm.
Describe the accuracy and precision for these measurements.
Precise but not accurate

13. Draw a target diagram that shows precision but not accuracy .

14. Draw a target diagram that shows accuracy but not precision

15. Draw a target diagram that shows both accuracy and precision

16. TOOLS WE NEED
TO READ TO BE
ACCURATE AND
PRECISE

17. Temperature Scales 00 K Fahrenheit Celsius Kelvin 32 ˚F 212 ˚F 180˚F
Boiling point of water
32 ˚F
212 ˚F
180˚F
100 ˚C
0 ˚C
100˚C
373 K
273 K
100 K
Freezing point of water
-273
00 K
Absolure Zero
Notice that 1 kelvin = 1 degree Celsius
KELVIN scale-absolute zero –temperatures do
not exist. ABSOLUTE 0=00 K

19. Reading a Meterstick
. l I I I I cm
First digit (known) = ?? cm
Second digit (known) = ? cm
Third digit (estimated) between
Length reported = cm
or cm
or cm

20. Learning Check . l8. . . . I . . . . I9. . . .I . . . . I10. . cm
What is the length of the line?
1) cm
2) cm
3) cm
How does your answer compare with your neighbor’s answer? Why or why not?
ARE YOU ACCURATE OR PRECISE?

21. Zero as a Measured Number
. l I I I I cm
What is the length of the line?
First digit ?? cm
Second digit ? cm
Last (estimated) digit is cm

22. Volume Displacement 25 mL
A solid displaces a matching volume of water when the solid is placed in water.
33 mL
25 mL

24. Record to nearest tenth.
190.2 g
37.4 g
105.6 g

25. 6.62mL
52.7 mL

26. Read from
bottom
HOW MUCH?
350 mL