Module 1 + 2 definitions

• 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 calipers 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 calipers and micrometers, 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