Analyzing Experiments
VARIABLES
INDEPENDENT VARIABLES
DEPENDENT VARIABLES
CONTROLLED EXPERIMENTS
What is the Problem?
 First step in the scientific method
 Establishes purpose
 Based on observations
 Stated as a question
Why Research?
 Learn more about the topic
 Pick out key words in the problem question
 Helps to make an educated hypothesis
 Gives insight into materials that may be needed
 Use internet, books, scientific magazines and articles,
scientific journals, scientists/teachers, interviews, prior
knowledge
What is a Hypothesis?
 Is not an opinion
 Is not a question. It is a statement.
 Is based on research and observations
 Must be testable.
 It is okay if it turns out to be wrong/unsupported by
data collected in experiment.
What is an Experiment?
 A way to test your hypothesis
 Allows you to gather data to make conclusions
 Contains more than one trial
 Contains variables:
 Controlled variables
 Independent (Manipulated) variables
 Dependant (Responding) variables
Ball Drop Experiment
 Problem: Will two balls of different masses fall at
the same rate?
 Research: Gravity will cause any thrown or
dropped ball to fall to the ground.
 Hypothesis: Galileo said that objects of different
masses fall at the same rate and will therefore hit the
ground at the same time (ignoring air resistance).
 Experiment: Drop two balls of different masses off
of a table. Observe to see if they hit the ground at the
same time.
What is a variable?
 Anything that a scientist can change in an
experiment
 What are some variables in the Ball Drop
Experiment?
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The mass of the ball
The size of the ball
The weight of the ball
The distance it falls
The height of the table
Who drops the ball
What is a Independent Variable?
 The one variable that is purposely changed
 Also called manipulated variable
 What should be the manipulated variable in the Ball
Drop Experiment?

The mass/type of ball
What is a Dependent Variable?
 Also called the responding variable
 The factor that MAY change in “response” to the
manipulated variable
 It “depends” on what was changed
 What is the Dependent variable in the Ball Drop
Experiment?

When it hit the floor/ time it takes to hit the floor
What is a Controlled Experiment?
 An experiment in which only one variable is
manipulated at a time.
 That means only the manipulated variable changes
and every other variable stays the same.
 What are some variables we need to “control” in the
Ball Drop Experiment?
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The size of the ball
The distance it falls
The height of the table
Who drops the ball
Analyze the Results
 Organize data from experiment into charts, tables,
and graphs
 Look for trends and/or patterns
 Identify discrepancies
 Supports claims in conclusions
How do I make Conclusions?
 Return to your problem question and try to supply some answer.
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(even if the answer is: “I still do not have an answer.”)
Summarize findings
Return to your hypothesis and compare your experiment results to
your hypothesis. Are they the same or different? Why do you think?
Make conjectures and support them with your data
Explain why your findings are important. How might they help
others?
Discuss possible problems with the experiment. How could it be
improved?
Discuss future experimentation that may help you answer your
question
Present new questions your experimentation results may have
unfolded
Drawing Conclusions
 Mary went downstairs. There was an aroma in the air. The table
was set with warm blueberry muffins, freshly squeezed orange
juice, and brewed coffee. A note was left on the table. It said,
"Dear Mary, Have a great day. Good Luck at your new job. Love,
Dan" Next to the note there was a wrapped present with a bow
on top.
 Who is Mary?
 A: a wife
B: a husband
C: a baker
D: a nice person
Drawing Conclusions
 Mary went downstairs. There was an aroma in the air. The table
was set with warm blueberry muffins, freshly squeezed orange
juice, and brewed coffee. A note was left on the table. It said,
"Dear Mary, Have a great day. Good Luck at your new job. Love,
Dan" Next to the note there was a wrapped present with a bow
on top.
 What time of day is it?
 A: morning
B: afternoon
C: evening
Drawing Conclusions
 Mary went downstairs. There was an aroma in the air. The table
was set with warm blueberry muffins, freshly squeezed orange
juice, and brewed coffee. A note was left on the table. It said,
"Dear Mary, Have a great day. Good Luck at your new job. Love,
Dan" Next to the note there was a wrapped present with a bow
on top.
 What was the purpose of the note?
 A: to inform
B: to entertain
C: to congratulate
D: to thank
Drawing Conclusions
 Mary went downstairs. There was an aroma in the air. The table
was set with warm blueberry muffins, freshly squeezed orange
juice, and brewed coffee. A note was left on the table. It said,
"Dear Mary, Have a great day. Good Luck at your new job. Love,
Dan" Next to the note there was a wrapped present with a bow
on top.
 Who is Dan?
 A: her husband
B: her boss
C: her neighbor
Drawing Conclusions
 Mary went downstairs. There was an aroma in the air. The table
was set with warm blueberry muffins, freshly squeezed orange
juice, and brewed coffee. A note was left on the table. It said,
"Dear Mary, Have a great day. Good Luck at your new job. Love,
Dan" Next to the note there was a wrapped present with a bow
on top.
 What is Mary's new job?
 A: store clerk
B: baker
C: real estate agent
D: not enough information given
Drawing Conclusions
 Mary went downstairs. There was an aroma in the air. The table
was set with warm blueberry muffins, freshly squeezed orange
juice, and brewed coffee. A note was left on the table. It said,
"Dear Mary, Have a great day. Good Luck at your new job. Love,
Dan" Next to the note there was a wrapped present with a bow
on top.
 Who probably made the muffins, orange juice, and,
coffee?
 A: Mary
B: Dan
Drawing Conclusions
 Mary went downstairs. There was an aroma in the air. The table
was set with warm blueberry muffins, freshly squeezed orange
juice, and brewed coffee. A note was left on the table. It said,
"Dear Mary, Have a great day. Good Luck at your new job. Love,
Dan" Next to the note there was a wrapped present with a bow
on top.
 Why was there a present on the table?
 A: to congratulate
B: a thank you gift
C: to say sorry
D: not enough information given
Drawing Conclusions
 Miss Amole is always trying to save money, but she also likes a
quality product. She decided to do an experiment to see if the
“cheap” paper towels were just as strong as the “expensive”
ones. She bought two types of paper towels: Brawny (expensive)
and Bounty (cheap). Miss Amole thought the Brawny paper
towels would be stronger since they were more expensive. She
placed both paper towels in a bowel that contained the same
amount of water. After soaking for one minute, Miss Amole rung
both paper towels out as best she could and unwrinkled them.
She then placed a soup can on the paper towels and observed
how long the paper towels could hold the can before tearing. The
Bounty held for 20 seconds and the Brawny held for 5 seconds.
 What conclusions can we make?
Drawing Conclusions
 The graph below shows the relationship between
maternal age and the incidence of children born
with Down syndrome (a condition that results in
an individual having an extra chromosome 21).
 What conclusion is best supported by the data?
 A. There is no risk of Down syndrome in children
born to mothers under age 34.
 B. The risk of Down syndrome increases
dramatically in children born to mothers after age
34.
 C. The risk of Down syndrome doubles in children
born to mothers for each year over the age of 34.
 D. There is no correlation between the number of
Down syndrome births and age.
Drawing Conclusions
 Environmental monitoring of a lake
 located to the southeast of a factory has
 shown a consistent decrease in pH over
 the period of a year. A researcher
 investigating the pH change hypothesizes that either a factory or a farm
along the river is responsible for the pH change. The river flows into the
lake.
 The researcher collects a water sample from locations Y and Z in the
diagram and runs pH analyses on each sample. He finds that the pH in
sample Z is lower than the pH in sample Y and concludes that the factory is
responsible for the low pH values in the lake.
 Based on the diagram and the researcher’s investigation, provide two
reasons why this may not be a valid conclusion. Describe how each reason
could invalidate the conclusion.