This document provides teaching notes for a PowerPoint presentation introducing different types of variables. It explains that the presentation defines and gives examples of categoric, ordered, discrete, and continuous variables, as outlined in a physics textbook. The notes provide guidance for using the presentation in a classroom, including revealing information step-by-step and asking questions to help students understand.

1. Teacher’s Notes
This sequence of slides is designed to introduce, and explain, the different
types of variables (categoric, ordered, discrete, continuous), as
explained on pages 360 in New Physics for You, 2006 & 2011 editions.
It should be used after the other PowerPoint on ‘Variables’.
Note : When you start this PowerPoint if you see a message about “Read-only embedded fonts” then you
are recommended to select “Open Read-Only” as this (i) gives a clearer font for those
at the back of the room and (ii) ensures that the text-highlighting of key words is correct.
On each slide the key points are revealed step by step,
at the click of your mouse (or the press of a key such as the space-bar).
Before making the next mouse-click you can ask questions of the class
or make statements about what is about to be revealed.
This should help students to become clearer about the ideas involved.
Naturally it pays to have quick practice-run first.
To start the slide-show, press function-key F5
(or right-click->Full Screen)
(to return to ‘normal view’ press the <Esc> key).
For more (free) PowerPoint presentations, visit www.physics4u.co.uk

2. How Science works:
Types of
Variables
N w Phy s ic s fo r Yo u, page 360
e

3. Learning Objectives
You should learn :
• About different types of variables,
• How to identify them when doing
your practical work.

4. Revision of variables
Can you
…an independent
remember what
dependent
…a …a control
is meant by…
variable?
variable?
variable?

5. Revision of variables Summary:
The independent variable
is the one that you change or select.
The dependent variable
is the one changes as a result,
and that you measure.
The control variables must not change,
so that it is a fair test.

6. Types of variables
There are 4 other types of variables that
you may meet.
Their names are:
• Categoric
• Ordered
• Discrete
• Continuous
We’ll look at two examples of each one.

7. Categoric variables
These have word labels.
Example 1
In this experiment
on conduction of heat:
The Categoric variables are:
copper, iron, glass

8. Categoric variables
These have word labels.
Example 2
In this experiment to find
the resistance of wires:
The Categoric variables could be:
copper wire, iron wire, steel wire, etc

9. Ordered variables
These are categoric variables
that can be ranked, in an order.
Example 1
In this experiment to find
the resistance of wires:
The Ordered variables could be:
thick copper wire,
thinner copper wire,
very thin copper wire.

10. Ordered variables
These are categoric variables
that can be ranked, in an order.
Example 2
In an experiment to investigate
a falling parachute:
The Ordered variables could be:
large parachute,
medium parachute,
small parachute.

11. Discrete variables
These variables can only have
whole number values, 1, 2, 3,…
Example 1
In an experiment to investigate
the stretching of a spring:
The discrete variables are:
1 weight, 2 weights, 3 weights, …

12. Discrete variables
These variables can only have
whole number values, 1, 2, 3,…
Example 2
In an experiment on the cooling
of an insulated beaker:
The discrete variables are:
number of layers of insulation
= 1 layer, 2 layers, 3 layers, …

13. Continuous variables
These variables can have
any numerical value.
Example 1
In this experiment to investigate
the stretching of a spring:
The continuous variable is:
length of the spring
= 15.1 cm, 15.5 cm, 15.9 cm …

14. Continuous variables
These variables can have
any numerical value.
Example 2
In this experiment to investigate
the cooling of water:
The continuous variable is:
the temperature of the water
= 70.6oC, 68.4oC, 66.2oC …

15. 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.

16. Learning Outcomes
You should now:
• Understand the difference between
- Categoric,
- Ordered,
- Discrete, and
- Continuous variables
• Be able to identify these variables
when doing your practical work.

17. For more details, see:
 New Physics for You, page 360
For more free PowerPoints, visit
 the web-site at www.physics4u.co.uk

18. If you are connected to the web at the
moment, click below to see what’s
available:
http://www.physics4u.co.uk/