# Shared Flashcard Set

## Details

How Science works
Key words for the AQA GCSE Sciences
20
Physics
04/22/2008

Term
 What is accuracy
Definition
 Accuracy is how close you are to the true value.
Term
 What is an independent variable?
Definition
 This is the varaible which you decide to change and choose the values to investigate.
Term
 What is a dependent variable?
Definition
 This is the variable which you cannot control and could be affected by the independent variable.  You have to measure this variable.
Term
 What is a categoric variable?
Definition
 This is a variable where the variable is made up of named groups.
Term
 What is a continuous variable?
Definition
 This is a varaible which could have any numerical value
Term
 What is a discrete variable?
Definition
 This is a variable which can only come in certan amounts.
Term
 What is systematic error
Definition
 This is an error caused by human error.  A badly designed experiment or measurement.  You can improve the experiment and therefore reduce this type of error.
Term
 What is random error?
Definition
 This is a type of error which you cannot control.  The only way to reduce this type of error is to carry out many repeats (better reliabilty).
Term
 What is zero error?
Definition
 Zero error is caused by a faulty measuring device.  For example if someone cut the first centimetre of a ruler.
Term
 What is range?
Definition
 Range is the samllest to largest measurement made.
Term
 What does precise mean?
Definition
 Precise describes the quality of a measuring device or the smallest interval it can measure to.  A cm ruler is less precise than a mm ruler.
Term
 What is a fair test and control variable.
Definition
 ANy valid experiment must have only one changing independent varaible otherwise you cannot be sure what caused the change in the dependent variable.
Term
 How can you improve the reliability of an experiment?
Definition
 If you repeat an experiment the results should be similar.  The more times you repeat an experiment, the more reliable the results will be.The experiment should also be repeated by another independent group to make sure results are unbiased.
Term
 When should you draw a line graph (scattergram) to represent your results.
Definition
 If the independent variable is a continuous varaible then your results should be displayed as a line graph/ scattergram.
Term
 When should you use a bar chart to represent your results.
Definition
 If the independent variable is a discrete or categoric variable then the results should be represented using a bar chart.
Term
 What should a good results table include?
Definition
 A good results table should include columns which have titles and relevant units describing the independent and dependent variable.Units should always be in the header row.The results should also be record to the precision of the measuring device.  For example if you measure length using a ruler with mm scale then the result should be recorded as 10.0 not 10.
Term
 What should a good line graph look like?
Definition
 The independent variable goes on the x axis and the dependent variable on the y axis.Each axis should have a title and units clearly labelled.Suitable and consistent scales on the axis.Results correctly plotted and checked.A straight line of best fit (use a ruler) or a smooth (no bumps) curved line of best fit.
Term
 What does random sampling mean?
Definition
 A sample chosen that allows all subjects an equal probability of being selected. It is not deliberately chosen.
Term
 What does the independent and dependent variable are proportional mean?
Definition
 Whatever happens to the independent variable will also happen to dependent variable
Term
 What does the independent and dependent variable are inversely proprtional mean?
Definition
 If the independent variable gets bigger (doubles to be specific) then the dependent variable gets smaller (halves).
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