Scientific Method
Observation
 This is the first stage in understanding a
problem that you are solving by conducting
an experiment.
 In this stage, you collect information from
your surroundings or from research.
Problem
 The specific problem or concept you are
investigating.
 Every step of the experiment is conducted
to solve this problem.
Variable
 A factor or condition that can exist in
differing amounts or types.
 Many experiments have 3 different types of
variables.
The 3 Variables
 Independent: The experimenter changes
this variable.
 Dependent: The variable that responds to
the changes of the independent variable.
The experimenter observes the outcomes of
the change.
 Control: The factor that
remains consistent.
Variables in Good
Experiments
 In a good experiment, there is only one
independent variable. That way, only one
factor creating change is observed at a
time.
 In a good experiment, the independent,
dependent, and control variables, can be
measured by the scientist.
Hypothesis
 An educated guess about how things work.
 Most of the time, a hypothesis is written like
this: “If ____ [I do this] ____, then ____ [this]
____ will happen.”
 This must be worded so that it can be tested
in your experiment.
 Do this by writing the hypothesis using your
independent variable and your dependent
variable.
Experiment
 Test your hypothesis by changing the
independent variable and observing the
changes of the dependent variable.
 Record the change of your dependent
variable.
 This is your data.
Experiment Participants
 People responding to your experiment.
 For example, you might ask people to
respond to a survey as your experiment.
 Collect identifying information that might
influence their response to the survey.
 For example: age, gender, geographic
location.
Experiment Tips
 Keep as many things in your experiment as
identical as possible so you isolate the
tested variable.
 If you have time, repeat the experiment!
That way you can find out if your results are
accurate.
Collecting Data
 Be consistent, careful, and accurate when you
take your measurements.
 There are 2 types of data

Qualitative – descriptions of qualities

Quantitative – quantities or numerical
measurements
 Numerical measurements are best.
 Take pictures as you conduct your experiment.
They will be extremely valuable in your
presentation.
Results
 An explanation of the data.
 Patterns are generally noted.
 Usually reported in a graph or chart to see
the pattern easier.
Conclusion
 The final step!
 State if the hypothesis was supported or not.
 It’s okay if the hypothesis is not supported!
 Explain why you think the hypothesis was
supported or not.
Lemonade
Experiment
Example of the Scientific Method
Observation
 Lemonade requires lemons, water, and
sugar.
 I try to watch how much sugar I consume.
 I wonder if I could use different sweeteners
like honey or agave nectar in my
lemonade?
Problem
 If I make my lemonade with agave nectar
or honey, then will it taste as sweet as
lemonade made with sugar?
The 3 Variables
 Independent: Type of sweetener – agave
nectar and honey
 Dependent: Taste of sweetness
 Control: Sugar
Lemonade Experiment
Hypothesis
 If I make lemonade using honey, then it will
be just as sweet as lemonade made with
sugar.
 If I make lemonade using agave nectar,
then it will be just as sweet as lemonade
made with sugar.
 Independent variable: honey or agave
nectar
 Dependent variable: sweetness
Experiment Set-Up
 I made 3 pitchers of lemonade
 Each pitcher has equal amounts of lemon
juice and water. In each pitcher, I mixed ¼
cup of lemon juice into 5 cups of water.
 Pitcher A: I added ½ cup sugar
 Pitcher B: I added ½ cup honey
 Pitcher C: I added ½ cup agave nectar
Experiment Set-Up
 Each participant received 3 clear plastic cups.
Each cup was labeled to match the pitcher
from which the lemonade was poured. Three
tablespoons of each lemonade were poured
into the corresponding plastic cup. Participants
drank the lemonade and ranked the sweetness
on a 1 – 5 scale, with one being not sweet to
five being very sweet.
 Keep in mind: all of this information should be
written in your procedures section of your report.
Experiment Title
 The effect of honey or agave nectar on the
sweetness of lemonade.
Experiment Participants
 25 people –
 12 males
 13 females
 Average age = 20 years
 Age matters in this experiment because
studies have shown that perceived
sweetness changes with age.
Data Sample
Participant
Pitcher A
Sweetness
Rating
Pitcher B
Sweetness
Rating
Pitcher C
Sweetness
Rating
A
4
2
4
B
4
2
3
Pictures
 Make sure you show:
 Procedure – making the lemonade, setting
up the pitchers and cups, participants
drinking lemonade
 Results – if anyone had a strong physical
reaction to drinking the lemonade, like if they
made a sour “pucker” face.
Results
 Pitcher A (sugar): Participants indicated an
average rand on the sweetness scale of 4,
sweet.
 Pitcher B (honey): Participants indicated an
average rank on the sweetness scale of 2,
somewhat sweet.
 Pitcher C (agave nectar): Participants
indicated an average rank on the
sweetness scale of 4, sweet.
Conclusion
 I I make lemonade using honey, then it will be
just as sweet as lemonade made with sugar.
NOT supported.
 If I make lemonade using agave nectar, then it
will be just as sweet as lemonade made with
sugar. Supported.
 Agave nectar might be perceived as sweeter
than honey. Another study to evaluate the
sweetness differences between honey and
agave nectar might provide more information
to determine whether or not this influenced
perceived sweetness of the lemonade.