1. Scientific MethodScientific Method

2. Put the steps in order…
Analyze Data Ask a Question
Experiment Hypothesis
Observation/Research
Conclusion
Theory
Scientific Law

3. Steps in the ScientificSteps in the Scientific
MethodMethod
 ObservationObservation (ask(ask
question)question)
 HypothesisHypothesis
 ExperimentExperiment
 Analyze DataAnalyze Data
 ConclusionConclusion
 TheoryTheory
 Scientific LawScientific Law

4. ObservationsObservations
 GatheredGathered
through yourthrough your
sensessenses
 A scientistA scientist
noticesnotices
something insomething in
theirtheir naturalnatural
worldworld

5. ObservationsObservations
 AnAn exampleexample of anof an
observationobservation mightmight
be noticing thatbe noticing that
heating CuCOheating CuCO33 aa
gas is released.gas is released.

6. ObservationsObservations
 AnotherAnother exampleexample
of an observationof an observation
might be noticingmight be noticing
that every timethat every time
that your sisterthat your sister
blows a bubbleblows a bubble
bigger than herbigger than her
head, it POPS!head, it POPS!

7. HypothesisHypothesis
 A suggestedA suggested
solution to thesolution to the
problem.problem.
 Must beMust be testabletestable
 PredictsPredicts anan
outcomeoutcome

8. HypothesisHypothesis
 AnAn example of aexample of a
hypothesishypothesis mightmight
be that the bubblebe that the bubble
pops because ofpops because of
the quality of thethe quality of the
gum.gum.

9. ExperimentExperiment
 A procedureA procedure
toto testtest thethe
hypothesis.hypothesis.

10. ExperimentExperiment
VariableVariable ––
factor in thefactor in the
experimentexperiment
that is beingthat is being
testedtested

11. ExperimentExperiment
A good orA good or
“valid”“valid”
experimentexperiment
will only testwill only test
ONEONE
variable!variable!

12. What is the Purpose of aWhat is the Purpose of a
Control?Control?
 Controls are NOT being
tested
 Controls are used for
COMPARISON

13. EXAMPLE:
 What variables does one need to
account for if one were to design an
experiment to test whether or not hot
water dissolves salt faster than cold
water? What would be the control?

14. Other Variables
 The factor that is changed is
known as the independent
variable.
 The factor that is measured or
observed is called the dependent
variable.

15. Example of Controls &Example of Controls &
VariablesVariables
 For example, suppose you want to figure
out the fastest route to walk home from
school.
 You will try several different routes and
time how long it takes you to get home by
each one.
 Since you are only interested in finding a
route that is fastest for you, you will do
the walking yourself.

16. What are the Variables inWhat are the Variables in
Your Experiment?Your Experiment?
 Varying the route is theVarying the route is the
independent variableindependent variable
 The time it takes is theThe time it takes is the
dependent variabledependent variable
 Keeping the same walkerKeeping the same walker
throughout makes the walker athroughout makes the walker a
control variable.control variable.

17. One more thing… it is best
to make several trials with
each independent variable.

18. How About Another Example?
 Pumpkin growers would like to know if
phosphorus has a key role in growing
GIANT PUMPKINS!
 THINK: How would you set up a
controlled experiment?

19. Remember:Remember:
 Two groups are used:
 the control & experimental groups
 There should be only one
variable tested at a time.
 Perform multiple trials

20. DataData
 Results of the
experiment
 May be
quantitative
(numbers) or
qualitative

21. DataData
 Must be
organized
 Can be
organized into
charts,
tables, or
graphs

22. ConclusionConclusion
 The answer to
the hypothesis
based on the
data obtained
from the
experiment

23. RetestRetest
In order to
verify the
results,
experiments
must be
retested.

24. Theory Vs. Law
 supported by
many
experiments.
 can be modified
 Ex. - Einstein's
Theory of
Relativity, Atomic
Theory
•Summarizes a
pattern in nature.
•No known
exceptions occur.
•Ex. - Law of
Universal
Gravitation, Law of
Conservation of
Mass, Gas Laws

25. Ticket-Out-The-Door: CP
 You want to buy a new car. You are interested
in three different models (model 1, model 2,
model 3). Today you are test driving the cars,
and you want the car with the best gas mileage.
 Independent Variable:
 Dependent Variable:

26. Ticket-Out-The-Door: CPH
Within a classroom setting, subjects were asked to
listen to a guest instructor. All subjects were given a
description of the instructor. Some subjects read a
description containing the phrase “People who know
him consider him to be a rather cold person...”, while
other people read a description where the word
“warm” was substituted for the word cold (otherwise,
the descriptions were identical). After the lecture,
subjects were asked to rate the instructor. Subjects
who were told the instructor was warm gave him
more favorable ratings compared to subjects who
were told that the instructor was cold.