Science- specific vocab

• Accuracy


  A measurement result close to the true value
• Calibration


  Marking a scale on a measuring instrument to ensure reliable results
• Data


  Information, either qualitative or quantitative
• Calibration Example

  Placing a thermometer in melting ice to see whether it reads zero, to check if it has been calibrated correctly
• measurement error


  the difference between a measured value and the true value
• Random error


  These cause readings to be spread about the true value, due to results varying in an unpredictable way from one measurement to the next. Random errors are present when any measurement is made, and cannot be corrected. The effect of random errors can be reduced

  by making more measurements and calculating a new mean.
• Systematic error


  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. Systematic errors cannot be dealt with by simple repeats. If a systematic error is suspected, the data collection should be repeated using a different technique or a different set of equipment, and the results compared.
• Zero error


  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.
• Fair test


  0nly one independent variable has been allowed ti affect the dependent variable
• Interval


  the quality between readings
• precision


  Precise measurements are ones in which there is very little spread about the mean value. Precision depends only on the extent of random errors – it gives no indication of how close results are to the true value.
• Repeatable

  A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results. Previously known as reliable.
• Reproducible


  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. Previously known as reliable.
• uncertainty


  ±
• control variable


  the one, in addition to the independent variable, that may affect the outcome of the investigation and therefore has to be kept constant or at least monitored
• dependent variable


  measured for every change in the independent variable
• independent variable


  changing value