Science
The Scientific Method:
Lesson 4:
The Scientific Method
Study Guide – Day 2
The BIG Question:
What are the steps
scientists use to
find answers to
their questions?
The BIG Question:
WHY do
scientists use
the Scientific
Method?
Does the weight
of a paper
airplane affect
how far it can fly?
Do dogs sleep
more than
human beings?
Does the
amount of light
a bean plant
receives affect
its growth?
Now it’s
your turn to
write a good
question!
The Scientific Method
Step 2:
Make a hypothesis.
The scientist tries to answer the question with a hypothesis. A hypothesis is an
“educated guess” that you make about what will happen during an experiment. However,
a good hypothesis is more than just a guess. A good hypothesis must explain what the
scientist has observed and must be testable.
For example, after observing children flying paper airplanes, the scientist may
make the hypothesis that a paper airplane will fly farther with a pointy nose than with a
flat nose. This hypothesis can be tested by an experiment.
An experiment may show that the hypothesis is either right or wrong. In science,
proving that a hypothesis is wrong can be just as valuable as proving that it is right.
Can sharks be
taught to
press a wooden
target to get
food?
Sharks CAN
learn to press
a target to get
their food.
The Scientific Method
Step 3:
Design and Perform the Experiment.
The scientist then performs an experiment. An experiment is a scientific test
of a hypothesis. It is important to plan the experiment carefully. First you must
identify the materials and tools that are needed. Then you must list the steps to be
followed to perform the experiment. These steps are known as the procedure.
A good experiment must follow certain rules:
The experiment must be repeatable.
The experiment must only test one variable at a time.
A variable is one of the things in an experiment that can be changed or controlled.
In a good experiment, a scientist changes one variable to see what effect this has on
something else. All other conditions are kept exactly the same. The scientist then
observes the effect of this change.
For example, in the experiment on paper airplanes, the scientist will choose one
variable to test, such as the shape of the nose. The scientist will change only this
variable and see how it affects how far the airplane will fly. All other conditions are
kept exactly the same. Each plane should be the same size, be made out of the same
type of paper, and have the same shape, except for the nose. Keeping all the other
conditions the same allows the scientist to see how the shape of the nose affects the
distance the plane flies.
Can sharks be
taught to
press a wooden
target to get
food?
Sharks CAN
learn to press
a target to get
their food.
variable = food
Good
Experiment
or
?
…must be repeatable.
…must only test one
variable at a time.
Carol wanted to find out
whether geranium plants would
grow better in sunlight or in
shade. She thought the plants
would grow better in sunlight.
Carol found two geraniums that
were the same size. She
placed one plant in a sunny
window and the other plant in a
shaded part of the house. She
tried to remember to water the
plants regularly, but sometimes
she forgot. At other times, she
gave more water to the shaded
plant than to the one in the
window.
Bob loves to garden and
wants to grow lots of pink
flowers for his pal Sandy. He
bought a special Flower
Power fertilizer to see if will
help plants produce more
flowers. He plants two plants
of the same size in separate
containers with the same
amount of potting soil. He
places one plant in a sunny
window and waters it every
day with fertilized water. He
places the other plant on a
shelf in a closet and waters it
with plain water every other
day.
Tina and Jazmine want
to know which hard
candy lasts the
longest. They choose
4 flavors of the candy.
Tina puts two different
candies in her mouth,
and at the same time,
Jazmine puts two
different candies in her
mouth. They use a
stopwatch to time how
long each candy lasts.
Step 4:
Record and analyze the data.
During the experiment, the scientist carefully records the results. Sometimes
scientists just observe and write facts to describe what they see, hear, smell, taste, or
touch. At other times, they use special tools to measure what they observe and then
record these measurements. The recorded facts and measurements from an experiment
are called data.
After recording the data, scientists then analyze the data and look to see if
there are any patterns. To help them find these patterns, scientists often organize
their results in the form of a table, graph, or diagram.
For example, in the experiment on paper airplanes, the scientist might use a tape
measure to measure how far each airplane flies. The data might then be recorded in the
chart below.
Type of
Plane
Distance Flown
Trial 1
Trial 2
Trial 3
Trial 4
Average
Flat Nosed
12 feet
15 feet
12 feet
9 feet
12 feet
Pointy Nosed
18 feet
15 feet
21 feet
18 feet
18 feet
Tools for Taking Measurements
beaker
thermometer
ruler
spring
scale
stop
watch
balance
Step 4:
Record and analyze the data.
During the experiment, the scientist carefully records the results. Sometimes
scientists just observe and write facts to describe what they see, hear, smell, taste, or
touch. At other times, they use special tools to measure what they observe and then
record these measurements. The recorded facts and measurements from an experiment
are called data.
After recording the data, scientists then analyze the data and look to see if
there are any patterns. To help them find these patterns, scientists often organize
their results in the form of a table, graph, or diagram.
For example, in the experiment on paper airplanes, the scientist might use a tape
measure to measure how far each airplane flies. The data might then be recorded in the
chart below.
Type of
Plane
Distance Flown
Trial 1
Trial 2
Trial 3
Trial 4
Average
Flat Nosed
12 feet
15 feet
12 feet
9 feet
12 feet
Pointy Nosed
18 feet
15 feet
21 feet
18 feet
18 feet
22
Key:
Distance Flown (feet)
20
18
Pointy-nosed
16
Flat-nosed
14
12
10
8
6
4
2
0
1
2
3
Trial
4
Water Temperature
Times the Shark
Pressed the Target for
Food
Step 5:
Draw a conclusion.
The scientist thinks about what the results show and uses the results to draw a
conclusion. A conclusion is the final answer to the question that was asked at the
beginning of the experiment.
For example, in the experiment on paper airplanes, the scientist can conclude that
the airplane with a pointy nose will fly farther than an airplane with a flat nose. The
scientist can conclude that this occurs because the pointy nose can cut through the air, jus
like the pointy tip of a knife can easily cut through a piece of cheese.
The results of a good experiment should clearly support or not support the
hypothesis. In the experiment on paper airplanes, the results supported the scientist’s
hypothesis that a paper airplane will fly farther with a pointy nose than with a flat nose.
What if the results of an experiment do not support the hypothesis? The
scientist may need to change the hypothesis or form a completely new hypothesis. Then
the scientist must do new experiments to test the new hypothesis.
Sharks are smart enough to
learn to press a wooden
target to get food.
Word Splash
1
Making Observations
2
Balloon Experiment
3-4
The Scientific Method
5-7
Sum
it up!
What did
you learn?
hypothesis
a guess about what will
happen in an experiment
experiment
a scientific test of
a hypothesis
data
recorded facts or
measurements in an
experiment
conclusion
variable
the final answer to the
question you asked at the
beginning of the experiment
one of the things that can
be changed or controlled
in an experiment