TOPIC: Scientific Method
Aim: Explain the steps of the
Scientific Method.
Do Now: Explain how you would find
your lost science text book
HW: Textbook. Read pgs. 6-13, p. 13
#’s 1-5 (Copy questions and write
answers underneath each question. )
p. 6 copy and define vocabulary
What is the Scientific Method?
• Model, or guide used to solve
problems and to get information
2
5
3
1
6
4
STEPS
1.Problem: in the form of a
QUESTION
• What you want to solve
Problem
Under what color light will
plants grow best?
2. Hypothesis: EDUCATED GUESS
• Suggested answer to the
problem
• HOW? Research problem
Hypothesis
I think the plant under green
light will grow best because
plants are green.
3. Experiment: TEST IF
HYPOTHESIS IS RIGHT OR WRONG
– Gather materials
– Design procedures
– Record results
Experiment
Grow the plants for 5 weeks. Each is placed
under a certain color light. They will get the
same amount of light, & will be watered
every 2 days. Their height will be measured
(in centimeters) once a week.
4. Observation: organize and analyze
data
• How? Graphs, charts…
Observations
Growth of plants
12
Height (cm)
10
8
6
4
2
1
2
3
4
PLANTS
5
6
5. Conclusion
• Is hypothesis right or wrong?
• Answers the question stated in the
problem
Conclusion
My hypothesis was wrong. Plants grow best
under blue light, not green light. The plant
under green light grew 11cm while the plant
under green light grew only 2 cm.
THEORY
• A hypothesis
supported by
MANY
experiments
• Thought to be
true but can
be changed
LAW
• A statement
that is believed
to be true
• Does not give an
explanation
PROBLEM
People
HYPOTHESIS
Hate
EXPERIMENT
Elephants
On
OBSERVATION
Couches
CONCLUSION
Let’s summarize…
1. List the steps of the scientific method.
2. Explain the difference between the problem and
the hypothesis.
3. What are you testing when performing an
experiment?
4. Describe an example of an observation.
5. What are some ways to organize your data?
6. Explain the difference between a theory and law.
Review:
1. The first step in the scientific method is
a. to state the problem
b. experimentation
c. to state the hypothesis d. observation
2. Information gained from experimentation and
observation is known as
a. theory b. data c. laws d. hypothesis
3. An educated guess to the problem of an
experiment is known as a
a. variable
b. theory
c. hypothesis
d. law
4. When performing an experiment, you are testing
the
a. problem b. hypothesis
c. data
d. conclusion
5. Your senses can be used to make a(n)
a. observation
b. conclusion
c. hypothesis
d. problem
Topic: Scientific Method
MI: Explain how a controlled experiment
is performed.
Do Now: (PASS UP HOMEWORK)
Complete Review Questions on the notes
sheet from yesterday.
HW: Ditto – Lab Safety (Quiz is
tomorrow!!!!)
Does fertilizer X help plant
growth?
Variable
• The one factor that is
different
• Factor that changes in each
set up
Controlled Experiment
• 2 groups:
1.Experimental group = contains the
VARIABLE
2. Control group = DOES NOT contain
the variable
– used to compare (normal setup)
Control Group
Experimental
Group
Everything
between the
2 groups
must be
exactly the
same except
for the
variable!!!
Topic: Scientific Method
MI: Explain how a controlled experiment
is performed.
Do Now: Explain the difference between
the experimental group and the control
group.
HW: Work on developing your science
fair problem.
2 types of variables
1. Independent Variable: the
factor that’s different between
exp. group and control group
1
Independent variable = ?
SUNLIGHT
2. Dependent Variable = what is
MEASURED
• data or results obtained
HEIGHT
Height = 12 cm
Height = 21 cm
What must be done to make results of
an experiment more reliable or valid?
• Repeat
experiment
• Use a larger
sample size
• Use only one
variable
Experiment
1. What is the independent variable?
2.What is the dependent variable?
3.Explain the difference between the
control group and experimental groups
in this experiment.
Let’s summarize…
1. Explain the difference between the control and
experimental groups.
2. Explain the difference between the
independent and dependent variables.
3. How can the results of an experiment be more
accurate?
Review:
To investigate how temperature affects seed
germination, a student placed 10 radish seeds of
the same variety on moist paper in each of 3 petri
dishes and placed the dishes in the following
environments:
Dish # 1: Refrigerator, 5ºC
Dish # 2: Room Temperature, 20ºC
Dish # 3: Incubator, 37ºC
1. Which factor is the variable in this
investigation?
a. temperature
b. kind of seeds
c. moisture
d. number of seeds
To investigate how temperature affects seed germination, a student
placed 10 radish seeds of the same variety on moist paper in
each of 3 petri dishes and placed the dishes in the following
environments:
Dish # 1: Refrigerator, 5ºC
Dish # 2: Room Temperature, 20ºC
Dish # 3: Incubator, 37ºC
2. The control group is
a. Dish #1
b. Dish #2
c. Dish #3
3. The dependent variable is the
a. temperature
b. how many days till germination
c. The # of seeds
d. the amount of water
4. What is the factor in an experiment that remains
constant?
a. control b. variable c. theory d. hypothesis
5. Which statement is true about the experimental
group (s) in an experiment?
a. It does not contain the independent variable.
b. It contains 2 variables.
c. It contains the independent variable.
d. It is exactly the same as the control group.
6. The results of one experiment carried out
by a research team would be considered
valid if
a. the experiment had no control setup
b. all the members of the research team came
to the same conclusion
c. the experiment had more than one variable
d. the experiment was repeated and the same
results were obtained each time
Topic: Scientific Method
Aim: How do we graph data?
Do Now: Complete the review
questions from yesterday's notes.
HW: Graphing Ditto
Beta-carotene supplements have been thought to
protect against cancer. A study was conducted
with 39,000 women aged 45 and up. Group A
received a beta-carotene supplement. Group B
received a placebo. Their health was studied
over their lifetime. Cancer rates for women
taking the beta-carotene supplement did not
really differ from the cancer rates of those
women taking the placebo.
Identify the independent variable, dependent
variable, control group, and experimental
group.
Students of different ages
were given the same jigsaw
puzzle to put together. They
were timed to see how long it
took to finish the puzzle.
What was the independent
variable?
• Ages of the students
• Different ages were tested
by the scientist
What was the dependent
variable?
• The time it to put the puzzle
together
• The time was measured by
the scientist
An investigation was done with an
electromagnetic system made from a
battery and wire wrapped around a nail.
Different sizes of nails were used.
The number of paper clips the
electromagnet could pick up was
measured.
Independent variable:
• Sizes of nails
• These were changed by the
scientist
Dependent variable:
• Number of paper clips picked
up
The higher the
temperature of water,
the faster an egg will
boil.
• Independent variable?
• temperature of water
• Dependent variable?
• time to cook an egg
Graphs
• Visual display of information or
data
• Organize and arrange data to
be easily understood
• Independent variable = “x” axis
• Dependent variable = “y” axis
• Title should compare the
independent to the dependent
As the independent variable increases,
the dependent variable...
3 main graphs (used in
science) are bar, line, &
pie
1. Bar : Comparing information
collected by counting
2. Circle Graph
(or Pie Chart)
• Different parts of
a whole quantity
• Slices represent
percentages of the
total
3. Line:
Data changes over time
Ex # 2: To investigate the effect of a substance on plant
growth, 2 bean plants of the same species were grown
under identical conditions with Substance Z added to the
soil of one of the plants. At the end of 2 weeks, the plant
grown with Substance Z was 12.5 cm tall. The plant
grown without Substance Z was 12.2cm tall. The
researcher concluded that the presence of Substance Z
causes the plants to grow taller.
What is the independent variable?
Substance Z
What is the dependent variable? height
Which setup is the control?
Plant without Substance Z
Ex #3: A student placed 5 geranium plants
of equal size in 5 environmental chambers.
Growing conditions were the same for each
plant except for the amount of water each
received. At the end of 20 days, the width of
the leaves was measured.
What is the independent variable?
What is the dependent variable?
Which setup is the experimental group?
5. An investigation was designed to determine
the effect of ultraviolet light on mold spore
growth. Two groups of mold spores were
grown under identical conditions, except
one group was exposed only to ultraviolet
light, while the other group was grown in
total darkness. In this investigation, the
group of mold spores grown without
receiving any ultraviolet light is known as
the
a. experimental variable
b. hypothesis
c. control
d. limiting factor