Learning Objectives: • Identify variables in a practical all• . • Decide on which variables to most change, measure and keep the same • Know the correct terms for some variables
Revision of variables Can you …an remember …a what is control …a meant independent dependent variable? by… variable? variable?
Revision of variables Summary:The independent variableis the one that you change or select.The dependent variableis the one changes as a result,and that you measure.The control variables must not change,so that it is a fair test.
In summary• Categoric These have word labels.• Ordered These categoric variables can be ranked, in an order.• Discrete These can only have whole number values.• Continuous These can have any numerical value.
Planning• When we plan an experiment we must always make sure that we choose a• suitable range• and• number of values for the independent variable.
Range• It is important in science to choose the correct range of Independent Variable.• E.g. the age of pupils in our school range from 11 18.
Fair Testing Assessment• A car manufacturer wanted to test the braking distances of its cars at different speeds.• What would you say the following should be? There is more information on the following slide – Independent Variable – – Dependent Variable – – Control Variables – – Range of Independent Variable- – Values of Independent Variable –
Fair Testing AssessmentBraking distances and speed.• Independent Variable – What am I changing in this investigation?• Dependent Variable – Because of what I am changing, what will I measure?• Control Variables – To make it a fair test what do I need to keep the same.• Control Variables – Ones I cannot Control – Which things will it be difficult to control?• Range of Independent Variable• Values of Independent Variable
Plenary• Use the post-it to mark which plan is the best• Write on it what you like about it