Topic 0-Accuracy worksheet virtual 2021 PDF

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Consiste de una toma de apuntes sobre el articulo el caul habla de la teoria de Kelvin, tambien da una breve explicacion sobre su procedencia y explicacion....

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BUCKINGHAM SCHOOL WORKSHEET ACCURACY AND PRECISION Name:

Subject: Biology

Grade: 10th

Date

Source: Science, Measurement, and Uncertainty: Accuracy and Precision. Demystifying Scientific Data: RET 2006, Rev 2 25

ACCURACY AND PRECISION (teacher )

A. Definitions: Accuracy – how close a measurement is to Precision – how close a measurement is to

the actual value of the quantity being measured. the consistent measurement reproduced.

B. Precision versus Accuracy: Look at each target and decide whether the “hits” are accurate, precise, both accurate and precise,or neither accurate nor precise: (Note: An accurate “hit” is a bull’s eye!)

Accurate: Yes/No Precise: Yes/No

Accurate: Yes/No Precise: Yes/No

Accurate: Yes/No Precise: Yes/No (teacher )

Precision Problems: A group of students worked in separate teams to measure how far they can flip a coin. Here is the data of the first group: 1 3,65

2 2,75

trials cm +/- 0.01 cm 3 4 5 2,80 3,77 3,68

6 4,65

7 2,68

1)• The average length is = 3.42 cm This is the mean.

cm

2)• Subtract the lowest value from the highest value: =1.97 cm This is the range or spread.

cm

3)• Divide this number by 2:

cm

= ± 0.98 cm This is the approximate ± range from the average. 4)• The precision of the measurement can be shown as mean ± range. The precision of the measurement was 3.42 cm ± 0.98

cm.

A second group of students obtained the following data: 1 4,45

2 2,70

trials cm +/- 0.01 cm 3 4 5 3,90 3,70 4,63

6 2,66

7. 2,95

3,57

• The mean length is = • The precision of the measurement was

3,57

cm.

±

0.9 8

cm

In comparing groups, the first or the second, which group was more precise or was the precision the same? Justify your answer Both groups were equally precise given that the spread was the same (1.97) and so was the +/- range from the average (+/-0.98)

C.Expressing Errors in Measurement : Scientists often express their uncertainty and error in measurement by giving a percent error. The percent error is defined as: (value is absolute)

(teache r)

Theoretical value= actual…. Known…….true value Answer the following four questions. Pay attention to the amount of decimals (2 max) and show your work! 1. Sheila uses her thermometer and finds the boiling point of ethyl alcohol to be 75 ⁰ C. She looks in a reference book and finds that the actual boiling point of ethyl alcohol is 80 ⁰ C. What is her percent error? %error= exp. value/the. value* 100 %error= 75⁰ C/80⁰ C*100 %error= 93.75⁰ C 2. The Handbook of Chemistry and Physics lists the density of a certain liquid to be 0.7988 g/mL. Jonathan experimentally finds this liquid to have a density of 0.7925 g/mL. The teacher allows up to +/- 0.500% error to make a “7” on the lab. Did Fred make an “7”? Prove your answer.

(teacher )

%error= exp. value/the. value* 100 %error= (0.7925g/ml)/(0.7988g/ml) *100 %error= 0.78g/ml Fred didn’t get a 7 because his experiment error percentage was higher than the one the teacher allowed. 3. A student took a calibrated 200.0-gram mass, weighed it on a laboratory balance, and found it read 196.5 g. What is the percent error of his balance? %error= exp. value/the. value* 100 %error= 196.5g/200.0g*100 %error= 98.25g 4. Accuracy is often expressed as an average of several measurements. Look at the target to the right. In your opinion, how well do the measurements on the target represent……? (Justify your opinion.) a. Accuracy? This is a very bad representation of accuracy, because the different measurements are far away from the center, meaning the accuracy to hit the target is low. b. Precision? The respresentation of precision in the target is equally low to the accuracy, as the different measurements are not consistent and are very far from one another.

Maximum marks 21

Marks 21 19-20 16-18 13-15 10-12 7-9 1-6

Grade 7 6 5 4 3 2 1

MARKS

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