How accurately does this ruler measure the red line, if each number stands for 1 cm?
A. 6 cm--it can only measure to the nearest cm.
Incorrect. An instrument can measure to the most precise limit you can read on the scale.
B. 6.0 cm--it can only measure to the nearest cm, but you put the decimal and 0 to show that you can estimate tenths.
Incorrect. If you can estimate tenths, then write them.
C. 5.8 cm—it can measure to the nearest cm.
Correct! The rule is correctly stated!
D. 5.82 cm—it can accurately measure to 5.8.
Incorrect. This ruler’s limit of precision is 1 cm increments.
A. The cheap thermometers are more precise than accurate.
Correct! They have precise markings, but do not always measure the “true” temperature.
B. The cheap thermometers are not precise, but they are accurate.
Incorrect. Accuracy refers to how close they come to the “true” temperature.
C. The cheap thermometers are easier to read than more expensive thermometers.
Incorrect. Think about accuracy and precision.
D. The cheap thermometers are not precise or even accurate.
Incorrect. They have precise markings.
Four physics students measured the density of a lead fishing weight three times each. The accepted scientific value for the density of lead based on a reference chart from the students' textbook is 11.34 g cm3 . The results of their experiments appear below:
|
Adriana
|
|
Tanner
|
|
Nicholas
|
|
Stephanie
|
||||
|
Trial
|
density
(in g cm3 ) |
Trial
|
density
(in g cm3 ) |
Trial
|
density
(in g cm3 ) |
Trial
|
density
(in g cm3 ) |
|||
|
1
|
11.31
|
1
|
11.43
|
1
|
11.58
|
1
|
11.62
|
|||
|
2
|
11.34
|
2
|
11.42
|
2
|
11.34
|
2
|
11.23
|
|||
|
3
|
11.37
|
3
|
11.41
|
3
|
11.54
|
3
|
11.72
|
|||
Looking at all four students’ results, which student exhibited the highest accuracy?
A. Adriana
Correct! Adriana’s results show high accuracy since they are all very close to the true or accepted value.
B. Tanner
Incorrect. While Tanner’s results are all very close to each other, they are not close to the true or accepted value.
C. Nicholas
Incorrect. Even though one of Nicholas’ results was exactly 11.34, the other two readings are not close to this result.
D. Stephanie
Incorrect. Stephanie’s results were the farthest from the accepted value.
Four physics students measured the density of a lead fishing weight three times each. The accepted scientific value for the density of lead based on a reference chart from the students' textbook is 11.34 g cm3 . The results of their experiments appear below:
|
Adriana
|
|
Tanner
|
|
Nicholas
|
|
Stephanie
|
||||
|
Trial
|
density
(in g cm3 ) |
Trial
|
density
(in g cm3 ) |
Trial
|
density
(in g cm3 ) |
Trial
|
density
(in g cm3 ) |
|||
|
1
|
11.31
|
1
|
11.43
|
1
|
11.58
|
1
|
11.62
|
|||
|
2
|
11.34
|
2
|
11.42
|
2
|
11.34
|
2
|
11.23
|
|||
|
3
|
11.37
|
3
|
11.41
|
3
|
11.54
|
3
|
11.72
|
|||
Which student had data that showed the greatest precision?
A. Adriana
Incorrect. Adriana’s results are not the closest together.
B. Tanner
Correct! Tanner’s results are all very close to each other.
C. Nicholas
Incorrect. Nicholas’ results are not the closest together.
D. Stephanie
Incorrect. Stephanie’s results are not the closest together.
In Chemistry class, the lab groups below recorded the mass of a product through three trials. Which lab group was the most precise in their measurements?
| Lab Group | Trial One | Trial Two | Trial Three |
| A | 121.45 g | 122.01 g | 130.20 g |
| B | 123.45 g | 122.90 g | 123.20 g |
| C | 120.90 g | 123.45 g | 124.00 g |
| D | 127.30 g | 124.50 g | 120.70 g |
A. Lab group A
Incorrect. The difference between measurements is too great.
B. Lab group B
Correct! The measurements are closest together!
C. Lab group C
Incorrect. The difference between measurements is too great.
D. Lab group D
Incorrect. The difference between measurements is too great.