The document outlines the experimental method in science, which involves asking questions and developing hypotheses, designing and carrying out research to test theories by manipulating the independent variable and measuring the dependent variable, and analyzing whether the findings support or refute the theory. It discusses the different types of hypotheses, provides examples of experimental hypotheses and studies, and explains the importance of controlling for extraneous variables that could influence the results.

1. How Science Works
Experimental method

2. Experimental Process
1. Ask questions and develop theories
about how, why and where things
happen
2. Develop these into a specific
hypothesis (predictions)
3. Design & Carry out research to test
these theories – what happens when
we try it out?

3. Experimental Process
Findings support
or refute theory =
refine theory

4. Hypotheses
• 2 types:
Experimental Hypothesis Null Hypothesis
(Alternative Hypothesis)
- A prediction of the outcome -Findings are due to chance
-There is no relationship or
difference as predicted

5. Try writing an Experimental & Null
hypothesis for these possible
studies
1. A study that aims to look at the effect of music
on concentration
2. A study that aims to look at the amount of TV a
child watches and their behaviour at school
3. A study that aims to see whether a task, such
as counting backwards from the number 15
after seeing a list of letters, will affect the
ability to recall of those letters

6. Experimental Hypotheses
You may wish to predict the direction of the effect
= Directional / One-tailed
e.g.
– Students’ performance will improve with practice
– Eating chocolate will increase happiness
– Taking regular exercise will decrease risk of heart
disease
• Alternatively, you can just say that there will be
an effect
= Non-directional / Two-tailed

8. Examples
1. Students remember more words when
recalling them in the same location in
which they were learnt than when in a
different location.
2. Recall of a story is affected by the length
of time since hearing the story.

9. Experimental Process
• Experiments are one of the most commonly used
methods in psychology
• An experiment is a research method in which the
researcher – the experimenter – has a high
degree of control.
• The experimenter controls/manipulates the
independent variable (IV) and measures the
dependent variable (DV)

10. Example
• If we were to conduct an experiment
on whether television distracts
students from studying, what would
be the IV and the DV?
HINT:
Look for what is being measured (DV)
first, IV is then easy to identify!

11. • Both IV & DV MUST be measurable =
Operationalise
• There are usually two values of the IV e.g.
– Noise or no noise
– Smoker or non-smoker
– Male or Female
• These determine the conditions of the
experiment
• The conditions can be arranged in several
different ways (There can be more than 2
conditions)

12. Other variables
• What else might affect the study?
• Any variable (except for the IV) that
can influence your findings =
extraneous variables
E.g.
Participant Variables = age, gender,
experience, emotion
Situational Variables = noise, light, time
of day, crowds, interruptions

13. • If an extraneous variable is NOT
controlled for and impacts the results =
Confounding variable