Language of Measurement

Question 1

What is Accuracy?

Answer 1

A measurement is considered accurate if it is judged to be close to true value

Question 2

Accuracy of an experiment is described how?

Answer 2

• It is not quantifiable (no numbers to describe accuracy)
  It is describes as less or more accurate

Question 3

Accuracy of an experiment are dependant on which type of error/effects?

Answer 3

Both systematic and random errors

Question 4

What is Precision?

Answer 4

A quality denoting the closeness of agreement between measured values obtained by repeated measurements.

Simple terms - How close acquired results are to each other

Question 5

Describe what can be infered from precision of an experiment:

Answer 5

High Precision
* Less randome errors
* Controlled variables remained controleed and consistent
Low Precision
* High random errors

Precision does not indicate how close values are to true value

Question 6

How can Precison be described?

Answer 6

Can be described numerically by measurements of imprecision

Eg: Standard deviation

Question 7

What is Resolution?

Answer 7

The smallest change in quantity that an instrument can detect

Question 8

What is Gradation?

Answer 8

The gradation is the marked changes on analogoue instruments (Eg: A burette has gradation of 0.1mL is there is a line for every 0.1mL)

Question 9

Describe what is the extent of measurements obtained from analogue instruments in terms of resolution

Answer 9

Analogue intruments wll have resolution to a maximum of half the gradation
(Eg: If gradation is 1mL, then resolution is 0.5mL)

Question 10

Describe what is the extent of measurements obtained from digital instruments in terms of resolution

Answer 10

Digital instruments will have resolution to a maximum number of decimal places
(Eg: If balance can measure to 3 decimal places, then resolution is 0.001g)

Question 11

What is True Value?

Answer 11

Value that would be obtained in an ideal measurement

Question 12

Describe the characteristics of the true value

Answer 12

• Considered unknowable
• In special case of a fundamental constant, the constant is considered to have a true value.

Question 13

What are some examples of known true values/fundamental constants

Answer 13

• Molar Gas Constant
• Avogadro Constant
• Molar Volume of ideal gas at SLC

Question 14

What does Repeatability refer to?

Answer 14

The ability to achieve the same or very similar results consistently if experiment is performed again.

Question 15

Describe some things that contribute to high repeatability

Answer 15

• Same experimenter
• Same equipment
• Same conditions
• Same location
• Same technique
• Successive measurement over a short period of time

Question 16

High repeatbility is linked to what aspect of measurement?

Answer 16

High precisions
If there is high precision = high repeatability

Question 17

What is Reproducibility

Answer 17

Ability to achieve same or very similar results if experiment performed by someone else

Question 18

Describe some factors that can impact the reproducibility of an experiment:

Answer 18

• Difference in experimenter
• Difference in equipment
• Difference in conditions
• Difference in location
• Technique may vary or be the same

Question 19

High reproducilibility is linked to what aspect of measurement?

Answer 19

High Accuracy
If high accuracy = high reproducibility