a control variable is one that must be kept constant for a fair test
DESCRIPTION
Control Variables. A control variable is one that must be kept constant for a fair test. You must make sure that you keep control variables constant throughout your experiment to ensure that you are carrying out a fair test. Example:. - PowerPoint PPT PresentationTRANSCRIPT
A control variable is one that must be kept constant for a fair test.
You must make sure that you keep control variables constant throughout your experiment to ensure that you are carrying out a fair test.
Control VariablesControl Variables
Example:
When investigating the effect of the number of batteries on the current in a circuit, the control variables would be:
Size of the batteries Thickness and type of the wire Length of wire Number and type of components in the circuit
Categoric VariablesCategoric Variables
Categoric variables are classes, names, labels or categories, e.g...
Categoric VariablesCategoric Variables
Makes of cars, e.g. Ford, Vauxhall, Mercedes States of matter, e.g. solid, liquid or gas
Colour of eyes, e.g. brown, green, blue
Months of the year, e.g. Jan, Feb, Mar...
Exam results, e.g. pass or fail Preferences, e.g. like or dislike
brown green blue eyes.
Discrete VariablesDiscrete Variables
Discrete variables can only have whole numbers.
Example:
The number of peas in a pod
The number of coils of wire in an electric motor
The number of dandelions in a square metre
The number of layers of insulation
The number of cells in an electric circuit
Ordered VariablesOrdered Variables
Ordered variables have a natural order to them, They can be used to describe objects, people, happenings and scientific events.
Ordered variables are not precise - if possible, use continuous variables in scientific work.
Ordered VariablesOrdered Variables
Cooler, Warmer
Taller, Shorter
Large, Medium, Small
Low, Middle, High
Continuous Variables
Continuous variables are measured and can have a decimal point.
The current or voltage in a circuit
Continuous VariablesContinuous Variables
The length of a leaf
The time taken to travel 1 metre
The mass of salt dissolved
If we measure height, the reading could be 1.56m, 1.562m, or 1.5623m, etc.
Example:
Identifying VariablesIdentifying Variables
Answer the following questions on types of variables...
Which Type of Variable?Which Type of Variable?
Drag these variables to the correct box...
Types of Variable - SummaryTypes of Variable - Summary
Point the cursor to review these types of variable...
End of Show