Modules 1 and 2 Definitions

Question 1

Absolute Uncertainties

Answer 1

The interval that a value is said to lie within, with a given
level of confidence.

Question 2

Accuracy

Answer 2

A measure of how close a measurement is to the true value.

Question 3

Analogue Apparatus

Answer 3

Measuring apparatus such as rulers, beakers and thermometers that rely on the experimenter reading off a scale to determine the measurement.

Question 4

Anomalies

Answer 4

Data points that don’t fit the pattern of the data. You should determine why an anomalous result has occurred before removing it.
Repeat readings help remove anomalies.

Question 5

Control Variables

Answer 5

Variables that must remain the same throughout an

experiment so as to not affect the results.

Question 6

Dependent Variables

Answer 6

The variable being measured in an experiment. It is
dependent on the independent variable. The dependent variable should be plotted
on the y-axis of a graph

Question 7

Digital Apparatus

Answer 7

Measuring apparatus such as ammeters, voltmeters and

digital callipers that digitally measure and display a measurement

Question 8

Fiducial Marker

Answer 8

A thin marker, such as a splint, that is used to ensure readings
are taken from the same place each time. They are used to improve the accuracy
of measurements.

Question 9

Gradient

Answer 9

The change in the y-axis value over the change in the x-axis value
between two points. If the graph is curved, a tangent can be drawn to calculate the
gradient at a specific point.

Question 10

Independent Variables

Answer 10

The variable that is changed by the experimenter in an

experiment. The independent variable should be plotted on the x-axis of a graph.

Question 11

Line of Best Fit

Answer 11

A line drawn on a graph to demonstrate the pattern in the plotted
data points

Question 12

Percentage Uncertainties

Answer 12

The uncertainty of a measurement, expressed as a

percentage of the recorded value.

Question 13

Precision

Answer 13

A measure of how close a measurement is to the mean value. It only
gives an indication of the magnitude of random errors, not how close data is to the
true value

Question 14

Prefixes

Answer 14

Added to the front of units to represent a power of ten change.

Question 15

Random Errors

Answer 15

Unpredictable variation between measurements that leads to a
spread of values about the true value. Random error can be reduced by taking
repeat measurements.

Question 16

Repeatable

Answer 16

The same experimenter can repeat a measurement using the same
method and equipment and obtain the same value.

Question 17

Reproducible

Answer 17

An experiment can be repeated by a different experimenter using
a different method and different apparatus, and still obtain the same results.

Question 18

Resolution

Answer 18

The smallest change in a quantity that causes a visible change in the
reading that a measuring instrument records.

Question 19

Resolution of Forces

Answer 19

The splitting of a force into its horizontal and vertical

components.

Question 20

Scalar Quantities

Answer 20

A quantity that only has a magnitude, without an associated

direction. Examples include speed, distance and temperature.

Question 21

SI Units

Answer 21

The standard units used in equations. They are: metres, kilograms,
seconds, amps, Kelvin and moles.

Question 22

Significant Figures

Answer 22

A measure of a measurement’s resolution. All numbers
except zero are counted as a significant figure. When zeros are found immediately
after a decimal place, they too are counted.

Question 23

Systematic Errors

Answer 23

Causes all readings to differ from the true value by a fixed
amount. Systematic error cannot be corrected by repeat readings, instead a
different technique or apparatus should be used.

Question 24

Triangle of Forces

Answer 24

A method of finding the resultant force of two forces. The two
forces are joined tip to tail and the result is then the vector that completes the
triangle.

Question 25

Vector Quantities

Answer 25

A quantity that has both a magnitude and an associated

direction. Examples include velocity, displacement and acceleration.

Question 26

Vernier Scales

Answer 26

The type of scale used on callipers and micrometres, that involve
reading from a fixed scale and a moving scale to produce accurate
measurements.

Question 27

Zero Errors

Answer 27

: A form of systematic error, caused when a measuring instrument
doesn’t read zero at a value of zero. This results in all measurements being offset
by a fixed amount.