Modules 1 and 2 Definitions Flashcards
Absolute Uncertainties
The interval that a value is said to lie within, with a given
level of confidence.
Accuracy
A measure of how close a measurement is to the true value.
Analogue Apparatus
Measuring apparatus such as rulers, beakers and thermometers that rely on the experimenter reading off a scale to determine the measurement.
Anomalies
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.
Control Variables
Variables that must remain the same throughout an
experiment so as to not affect the results.
Dependent Variables
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
Digital Apparatus
Measuring apparatus such as ammeters, voltmeters and
digital callipers that digitally measure and display a measurement
Fiducial Marker
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.
Gradient
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.
Independent Variables
The variable that is changed by the experimenter in an
experiment. The independent variable should be plotted on the x-axis of a graph.
Line of Best Fit
A line drawn on a graph to demonstrate the pattern in the plotted
data points
Percentage Uncertainties
The uncertainty of a measurement, expressed as a
percentage of the recorded value.
Precision
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
Prefixes
Added to the front of units to represent a power of ten change.
Random Errors
Unpredictable variation between measurements that leads to a
spread of values about the true value. Random error can be reduced by taking
repeat measurements.
Repeatable
The same experimenter can repeat a measurement using the same
method and equipment and obtain the same value.
Reproducible
An experiment can be repeated by a different experimenter using
a different method and different apparatus, and still obtain the same results.
Resolution
The smallest change in a quantity that causes a visible change in the
reading that a measuring instrument records.
Resolution of Forces
The splitting of a force into its horizontal and vertical
components.
Scalar Quantities
A quantity that only has a magnitude, without an associated
direction. Examples include speed, distance and temperature.
SI Units
The standard units used in equations. They are: metres, kilograms,
seconds, amps, Kelvin and moles.
Significant Figures
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.
Systematic Errors
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.
Triangle of Forces
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.
Vector Quantities
A quantity that has both a magnitude and an associated
direction. Examples include velocity, displacement and acceleration.
Vernier Scales
The type of scale used on callipers and micrometres, that involve
reading from a fixed scale and a moving scale to produce accurate
measurements.
Zero Errors
: 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.
