Working Scientifically

Question 1

Accuracy

Answer 1

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

Question 2

Calibration

Answer 2

Marking a scale on a measuring instrument. This involves establishing the relationship between indications of a measuring instrument and standard or reference quantity values, which must be applied.

Question 3

Data

Answer 3

Information, either qualitative or quantitative, that has been collected.

Question 4

Error

Answer 4

See also uncertainty

Question 5

Measurement error

Answer 5

The difference between a measured value and the true value.

Question 6

Anomalies

Answer 6

These are values in a set of results which are judged not to be part of the variation caused by random uncertainty.

Question 7

Random error

Answer 7

These cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next.

Question 8

Systematic error

Answer 8

These cause readings to differ from the true value by a consistent amount each time a measurement is made. Sources of systematic error can include the environment, methods of observation or instruments used.

Question 9

Zero error

Answer 9

Any indication that a measuring system gives a false reading when the true value of a measured quantity is zero, eg the needle on an ammeter failing to return to zero when no current flows. A zero error may result in a systematic uncertainty.

Question 10

Evidence

Answer 10

Data which is shown to be valid

Question 11

Fair test

Answer 11

A fair test is one in which only the independent variable has been allowed to affect the dependent variable.

Question 12

Hypothesis

Answer 12

A proposal intended to explain certain facts or observations.

Question 13

Interval

Answer 13

The quantity between readings, eg a set of 11 readings equally spaced over a distance of 1 metre would give an interval of 10 centimetres.

Question 14

Precision

Answer 14

Precise measurements are ones in which there is very little spread about the mean value.

Question 15

Prediction

Answer 15

A prediction is a statement suggesting what will happen in the future, based on observation, experience or a hypothesis.

Question 16

Range

Answer 16

The maximum and minimum values of the independent or dependent variables; important in ensuring that any pattern is detected.

Question 17

Repeatable

Answer 17

A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results.

Question 18

Reproducible

Answer 18

A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained.

Question 19

Resolution

Answer 19

This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.

Question 20

Sketch graph

Answer 20

A line graph, not necessarily on a grid, that shows the general shape of the relationship between two variables. It will not have any points plotted and although the axes should be labelled they may not be scaled.

Question 21

Treu value

Answer 21

This is the value that would be obtained in an ideal measurement.

Question 22

Uncertainty

Answer 22

The interval within which the true value can be expected to lie. Whenever a measurement is made, there will always be some uncertainty or doubt about the result obtained.

Question 23

Validity

Answer 23

Suitability of the investigative procedure to answer the question being asked.

Question 24

Valid conclusion

Answer 24

A conclusion supported by valid data, obtained from an appropriate experimental design and based on sound reasoning.

Question 25

Variables

Answer 25

These are physical, chemical or biological quantities or characteristics.

Question 26

Categoric

Answer 26

Categoric variables have values that are labels, eg names of plants or types of material.

Question 27

Continuous

Answer 27

Continuous variables can have values (called a quantity) that can be given a magnitude either by counting (as in the case of the number of shrimp) or by measurement (eg light intensity, flow rate etc). Previously known as discrete variable.

Question 28

Control

Answer 28

Control variable is one which may, in addition to the independent variable, affect th

Question 29

Dependant

Answer 29

Dependent variable is the variable of which the value is measured for each and every change in the independent variable.

Question 30

Independant

Answer 30

Independent variable is the variable for which values are changed or selected by the investigator.