Scientific Method Review
Run this PPT show to help you
review for your midterm.
The PROBLEM of an
experiment is in the form of
a ____.
Question
A ______ is an EDUCATED
GUESS to the problem of
the experiment.
Hypothesis
The hypothesis is based
on
background research
The ___________ states
whether your hypothesis is
correct or incorrect.
conclusion
What would make the results of an
experiment carried out by a
research team VALID or more
RELIAABLE?
• The experiment was repeated and
the same results were obtained
each time.
• Use a larger sample size.
The ________________does
not contain the independent
variable.
control group
What is MEASURED is known
as the ______ variable.
dependent
A new
idea that IS TESTED in
a scientific experiment is
known as the ________.
hypothesis
The results of one experiment carried
out by a research team would be
considered valid if
1. the experiment had no control
setup
2. all the members of the research
team came to the same conclusion
3. the experiment had more than one
variable
4. the experiment was repeated and
the same results were obtained
each time
Which is the dependent
variable in Amelia's
experiment?
1. the number of bean
plants in each group
2. the amount of water
given daily to each plant
3. the height of each bean
plant
4. the amount of fertilizer
given to each group of
bean plants
A new idea that is tested in a
scientific experiment is known as
a(an)
1. theory
2. hypothesis
3. inference
4. observation
Which statement about the use of independent
variables in controlled experiments is correct?
1. A different independent variable must be used
each time an experiment is repeated.
2. The independent variables must involve time.
3. Only one independent variable is used for
each experiment.
4. The independent variables state the problem
being tested.
Why do scientists consider any hypothesis
valuable?
1. A hypothesis requires no further investigation.
2. A hypothesis may lead to further investigation
even if it is disproved by the experiment.
3. A hypothesis requires no further investigation
if it is proved by the experiment.
4. A hypothesis can be used to explain a
conclusion even if it is disproved by the
experiment.
The first step in the scientific
method is
a. to state the problem
b. experimentation
c. to state the hypothesis
d. observation
An educated guess to the
problem of an experiment
is known as a
a. variable
b. theory
c. hypothesis
d. law
When performing an
experiment, you are testing
the
a. problem
b. hypothesis
c. data
d. conclusion
The hypothesis is based on
the
1.conclusion
2.dependent variable
3.data collected
4.background research
Your senses can be used to
make a(n)
a. observation
b. conclusion
c. hypothesis
d. problem
Which statement represents an
observation?
a. Does the vitamin supplement affect plant
growth?
b. The plants under blue light grew 10cm
more than plants under yellow light.
c. 60 grams of drug X was administered to
group A. The new drug was not
administered to group B.
d. I think the vitamin supplement will help
pants grow taller.
Which statement represents the problem of
an experiment?
a. Does the vitamin supplement affect plant
growth?
b. The plants under blue light grew 10cm
more than plants under yellow light.
c. 60 grams of drug X was administered to
group A. The new drug was not
administered to group B.
d. I think the vitamin supplement will help
pants grow taller.
Which statement represents a hypothesis?
a. Does the vitamin supplement affect plant
growth?
b. The plants under blue light grew 10cm
more than plants under yellow light.
c. 60 grams of drug X was administered to
group A. The new drug was not
administered to group B.
d. I think the vitamin supplement will help
pants grow taller.
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
did not receive the beta-carotene supplement.
Their health was studied over their lifetime.
Cancer rates for women taking the betacarotene supplement did not really differ from
the cancer rates of those women taking the
placebo.
Identify the independent variable.
Beta-carotene supplement
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
did not receive the beta-carotene supplement.
Their health was studied over their lifetime.
Cancer rates for women taking the betacarotene supplement did not really differ from
the cancer rates of those women taking the
placebo.
Identify the dependent variable.
Their health
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
did not receive the beta-carotene supplement.
Their health was studied over their lifetime.
Cancer rates for women taking the betacarotene supplement did not really differ from
the cancer rates of those women taking the
placebo.
Identify the control group.
Group B (did not receive the beta-carotene
supplement)
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 experimental group.
Group A (received the beta-carotene
supplement)
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
did not receive the beta-carotene supplement.
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 2 constants or controls.
Gender (all women)
Amount of food eaten
Number of women in each group
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
did not receive the beta-carotene supplement.
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.
How can the results of this experiment be made
more valid?
Repeat the experiment.
Use a larger sample size
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.
Identify the independent variable.
Substance Z
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.
Identify the dependent variable.
Plant height (how tall the plant grew)
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.
Identify the control group.
The group that did not receive Substance Z.
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.
Identify the experimental group.
The group that received Substance Z.
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.
Identify 2 constants or controls.
Same species
Amount of water
Amount of sunlight
Temperature
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.
How can the results of this experiment be
made more valid?
Repeat the experiment.
Use a larger sample size.
To test the effect of hormones on plant
growth, 6 potted plant seedlings of the
same species were measured and then
sprayed with a growth hormone. After 4
weeks of growth under ideal conditions,
the plants were measured again.
How would you set up the control group?
There should be another group with 6 plants that
DO NOT receive water.
To test the effect of hormones on plant
growth, 6 potted plant seedlings of the
same species were measured and then
sprayed with a growth hormone. After 4
weeks of growth under ideal conditions,
the plants were measured again.
Identify the independent and dependent
variables.
Independent variable: Growth hormone
Dependent variable: Length of the seedling
To test the effect of hormones on plant
growth, 6 potted plant seedlings of the
same species were measured and then
sprayed with a growth hormone. After 4
weeks of growth under ideal conditions,
the plants were measured again.
Identify 2 factors that must be kept constant.
The amount of water each plant receives.
The temperature the plants were kept.
The species of plant used.
The amount of soil in each pot.