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SueM How Sci Works
How Science Works Key Words
Question | Answer |
---|---|
A fair test | An investigation or experiment where only the independent variable has been allowed to affect the dependent variable. This means only changing one variable and keeping everything else the same. |
Independent variable | The variable that you change to see what happens. |
Dependent variable | The variable that you measure to see how it has changed. |
Controlled variable | A variable which might affect the Dependent variable. It must be kept constant to make sure that the only thing affecting the Dependent variable is the Independent variable. |
Continuous variables | Variables that can have any numerical value. You should use a line graph to show this type of data. |
Discrete variables | Variables that are described by specific numbers. You should use a bar chart to show this type of data |
Categoric variables | Variables that are described by labels. You should use a bar chart to show this type of data. |
Ordered variables | Variables that are put in order but not measured. You should use a list to show this type of data. |
Accuracy | How close a measurement is to its true value. |
Precision | How small a measurement is. Millimetres are more precise than centimetres because they are smaller. |
Reliability | If someone else can repeat your measurements and get the same results then your results are reliable. Carrying out repeat measurements checks the reliability of your results. |
Validity | Your results must be valid if you are going to be able to draw a conclusion from them. To get valid results you need to carry out a fair test. |
Random errors | Errors caused by factors we can’t control, like tiny temperature changes in a room. They can also happen if you make a mistake – like pushing the stopwatch button too early. |
Systematic errors | Errors caused by inaccurate equipment, equipment that doesn’t zero properly or by problems with a method. |