Term | Definition |
Accurate | A measurement is considered to be accurate if it is judged to be close to the true value. |
Anomalous results | Results that do not match the pattern seen in the other data collected or are well outside the range of other repeat readings. They should be retested and if necessary discarded. |
Bar chart | A chart with rectangular bars with length proportional to the values they represent. The bars should be of equal width and are usually plotted horizontally or vertically. Also called a bar graph. |
Best-fit | Straight line or curve best suited to experimental results when plotted on a graph. |
Bias | Your Results are bias if your scientific judgement has been affected by something. E.g. your employers or politicians |
Calibration | Marking even intervals on a scale between two known fixed points. |
Control group | In an experiment to determine the effect of changing a single variable, a control group is often set up in which the independent variable is not changed, thus enabling a comparison to be made. |
Curved line | Line of changing gradient. |
Data | Information, either qualitative or quantitative, that has been collected. |
Directly proportional | A relationship that, when drawn on a line graph, shows a positive linear relationship that passes through the origin. |
Error | Somtimes called an uncertainty. |
Error- systematic | Causes readings to be spread about some value of the than the true value, due to results differing from the true value by a consistent amount each time a measurement is made. Can be due to environment, methods of observation or instruments used. |
Error-random | Causes readings to be spread about the true value, due to results varying in an unpredictable way form one measurement to the next. Random errors are present whenever any measurement is made and cannot be corrected. |
Error-zero | Any indication that a measuring system gives a false reading when the true value of the a measured quantity is zero. For example, the needle on an ammeter failing to return to zero when no current flows. |
Errror-human | Often present in the collection of data, and may be random or systematic. For example the effect of human reaction time when recording short time intervals using a stop watch. |
Estimated | Calculated approximately the value of something. |
Evidence | Data which have been shown to be valid. |
Extrapolation | Making an estimate beyond the range of results. |
Fair Test | A fair test is one in which only the independent variable has been allowed to affect the dependent variable. |
Gradient | Rate of change of two quantities on a graph; change in y/change in x. |
Hazard | A hazard is something ( for example, an object, a property of a substance or an activity) that can cause harm. |
Hypothesis | A proposal intended to explain certain facts or observations. |
Interpolation | Making an estimate beyond the range of results in a range. |
Interval | The quantity between readings, for example, a set of 11 readings equally spaced over a distance of 1m would give an interval of 10cm. |
Linear | A line of constant gradient on a graph. |
Line graph | Used when both variables are continuous. The line should normally be a line of best fit, and may be straight or a smooth curve. (Exceptionally, in some (mainly biological) investigations the line may be a ‘point to point’ line. |
Line of best fit | Straight line or curve best suited to experimental results when plotted on a graph. |
Magnitude | Size of something. |
Mean | The arithmetical average of a series of numbers. |
Monitor | Observations made over a period of time. |
Opinion | A belief not backed up by facts or evidence. |
Precise | A precise measurement is one 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. |
Precision | A precise set of repeat readings will be closely grouped together. |
Prediction | A forecast or statement about the way something will happen in the future. In science it is not just a simple guess because it is based on some prior knowledge or hypothesis. |
Random | Having no regular pattern. |
Range | The maximum and minimum of values of the independent or dependent variables; important in ensuring any pattern is detected. |
Relationship | The link between the variables that were investigated. |
Repeatable | A measurement is repeatable if the original experimenter repeats the investigation using same method and equipment and obtains the same results. |
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. |
Resolution | This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading. |
Risk | The likelihood that a hazard will actually cause harm. We can reduce risk by identifying the hazard and doing something to protect against that hazard. |
Straight line | Line of constant gradient. |
Trial run | Preliminary work that is often done to establish a suitable range or interval for the main investigation. |
Uncertainty | A measure of the possible range of values of a reading or outcome. |
Valid | Suitability of the investigation procedure to answer the question being asked. |
Variable | Physical, chemical or biological quantity or characteristic. |
Variable-Categoric | Categoric variables have values that are labels. For example names of plants or types of material. |
Variable-Continuous | Can have values (called a quantity) that can be given by measurement (for example, light intensity, flow rate etc.) |
Variable-Control | A variable which may, in addition to the independent variable, affect the outcome of the investigation and therefore has to be kept constant or at least monitored. |
Variable-Dependent | The variable for which the value is measured for each and every change in the independent variable. |
Variable-Independent | The variable for which values are changed, or selected, by the investigator. |