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 ___________ states
whether your hypothesis is
correct or incorrect.
conclusion
What would make the results of an
experiment carried out by a
research team valid?
The experiment was repeated and the
same results were obtained
each time.
The _______ group does not
contain the independent
variable.
control
What is measured is known
as the ______ variable.
dependent
A new
idea that is tested in a
scientific experiment is
known as the ________.
hypothesis
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.
1. 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.
2. 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.
3. Give 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.
You studied the effect of the amount of fish food on
the mass of goldfish. One tank of goldfish is fed the
normal amount of food once a day. A second tank of
goldfish was fed twice a day. A third tank of goldfish
was fed three times a day. The fish's mass was
measured three times a week.
1. State the problem.
What is the effect of the amount of fish food
on the mass of goldfish?
2. Give a possible hypothesis.
I think that feeding the goldfish three times a day
will increase the mass of the goldfish the most.
You studied the effect of the amount of fish food on
the mass of goldfish. One tank of goldfish is fed the
normal amount of food once a day. A second tank of
goldfish was fed twice a day. A third tank of goldfish
was fed three times a day. The fish's mass was
measured three times a week.
3. Identify the independent variable.
The amount of food
4. Identify the control group.
The group of goldfish that were fed once a day.
You studied the effect of the amount of fish food on the mass of
goldfish. One tank of goldfish is fed the normal amount of food
once a day. A second tank of goldfish was fed twice a day. A
third tank of goldfish was fed three times a day. The fish's mass
was measured three times a week.
3. Identify the dependent variable.
The mass of the goldfish.
4. Identify 2 controls (factors that must remain constant).
Amount of fish in each group
Temperature of the water
Amount of light the fish are exposed to
The original mass of the fish
Identify the
independent
variable.
280
260
240
220
200
Water temperature
180
160
140
120
Identify the
independent
variable.
100
80
60
40
20
Average water flea
heart rate
5
10
15
20
25
30 35
You want to test which size soccer is easier to
juggle with your feet. You test the size 3, size 4,
and size 5 ball. You count the number of seconds
the ball stays in the air for each trial. You allow
yourself to use both feet, knees and head to
juggle the ball.
1. Identify the independent variable.
The size of the soccer balls.
2. Identify the dependent variable.
The number of seconds the ball stays in the air.
You want to test which size soccer is easier to
juggle with your feet. You test the size 3, size 4,
and size 5 ball. You count the number of seconds
the ball stays in the air for each trial. You allow
yourself to use both feet, knees and head to
juggle the ball.
3. What can be done to increase the validity of
the experiment.
Repeat the experiment.
Use a larger sample size.
State the
relationship
between the
average water flea
heart rate and
water temperature.
280
260
240
220
200
180
160
140
120
As water
temperature
increases, the
average water flea
heart rate
increases.
100
80
60
40
20
5
10
15
20
25
30 35
What is the average
flea heart rate at
15ºC?
280
260
240
220
200
118 beats/min
180
160
140
120
What is the average
flea heart rate at
30ºC?
100
80
60
40
20
240 beats/min
5
10
15
20
25
30 35
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
Why do scientists make graphs of data from
experiments?
1. to observe general trends and patterns in
the data
2. to make the observed data more
accurate
3. to prevent errors in measuring data
4. to help change the original data tables
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.
An investigation is carried out to determine the
effect of exercise on the rate at which a
person can squeeze a clothespin.
In this investigation, the independent variable is
the
1. control
2. exercise
3. rate of squeezing
4. number of participants
An investigation is carried out to determine the
effect of exercise on the rate at which a
person can squeeze a clothespin.
In this investigation, the dependent variable is the
1. control
2. exercise
3. rate of squeezing
4. number of participants
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.