Brainlag PlusVariables, fair tests, anomalies, accuracy and precision, random and systematic errors, and the words examiners use about investigations.
Three kinds of variable
The independent variable is the one you change on purpose.
The dependent variable is the one you measure to see the effect. Control variables are kept the same, so that only the independent variable can cause a change. Then the test is valid: it answers the question it set out to.
- investigation: does temperature change how fast amylase breaks down starch?
- independent: the temperature
- dependent: the time until iodine no longer turns blue-black
- control: the volume of amylase, the starch concentration, the pH
The rest of this lesson and its 10 practice questions are in Plus.
Screen 1 of 4, free to read.
- 10 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards