The Scientific Method
The scientific method is a process used by scientists to study the world around them. It can also
be used to test whether any statement is accurate. You can use the scientific method to study
a leaf, a dog, an ocean, or the entire Universe. We all have questions about the world. The
scientific method is there to test if your answer is correct. You could ask, "Why do dogs and
cats have hair?" One answer might be that it keeps them warm. A good scientist would then
come up with an experiment to test whether the statement was accurate. BOOM! It's the
scientific method in action.
1. IDENTIFY THE PROBLEM
The scientific method starts with identifying a problem and forming a question that can be
tested. A scientific question can be answered by making observations with your five senses
and gathering evidence. The question you ask needs to be something you can measure, so
you can compare results you are interested in. For example, “How does fertilizer affect plant
growth?” would be a testable scientific question. It’s important to do background research
to find out what’s already written about your question before starting your experiment.
2. FORM A HYPOTHESIS
The second step in the scientific method is to form a hypothesis. A hypothesis is a possible
explanation for a set of observations or an answer to a scientific question. A hypothesis must
be testable and measurable. This means that researchers must be able to carry out investigations and gather evidence that will either support or disprove the hypothesis. Many trials
will be needed before a hypothesis can be accepted as true. A hypothesis is written as an
“If… then…” statement. For example, “If I give my plants fertilizer in the spring, then they
will produce more flowers,” is a simple hypothesis about how plants grow. In this example,
you can measure the number of flowers.
3. DESIGN AN EXPERIMENT
The next step in the scientific method is to test the hypothesis by designing an experiment.
This includes creating a list of materials and a procedure— a step-by-step explanation of
how to conduct the experiment. Scientists must be careful in how they design an experiment to make sure that it tests exactly what the hypothesis states. A proper experiment
compares two or more things but changes only one variable—factors that change in an experiment. This type of experiment is called a controlled experiment. For example, when testing the affects of fertilizer on plants, you would test an experimental group (with fertilizer)
and a control group (without fertilizer). Then you would compare the results of the groups.
Types of Variables

Independent Variable– the variable that is tested and changed by the scientist.
֍ Ex. The amount of fertilizer used on your plants.

Dependent Variable– the variable that is measured by the scientist and
changes as a result of the independent variable.
֍ Ex. How many flowers grow on the plant.

Controlled Variable– the variables that are kept the same (constant)
throughout the entire experiment.
֍ Ex. Same type of plant, same amount of light and water
4. PERFORM AN EXPERIMENT
Keeping detailed, accurate records is an important part of the scientific method. Before you
begin your experiment, create a table in which to record your data. Data are the facts, figures, and other evidence gathered through observations. A data table provides you with an
organized way to collect and record your observations. For example, your data table should
list the independent variable (amount of fertilizer) in the first column and the dependent
variable (number of flowers) in the second column. Then you can use your table to create a
graph. Graphs help you understand and use that data. Graphs make it easy to identify
trends and make predictions. The x-axis of your graph represents the independent
variable, while the y-axis of your graph represents the dependent variable.
5. ANALYZE THE DATA
The next step in the scientific method is to analyze the data. Data analysis is the process of
interpreting the meaning of the data we have collected, organized, and displayed in the
form of a table or graph. The process involves looking for patterns—similarities, differences,
trends, and other relationships—and thinking about what these patterns might mean. The
scientist then summarizes their findings and relates them to their hypothesis. For example,
in your analysis of your plant experiment, you would refer to your table/graph to describe
any relationships you observed between the plants with and without fertilizer.
6. COMMINCATE THE RESULTS
The last step of the scientific method is to communicate the results. After you gathered and
analyzed your data, you draw a conclusion about your hypothesis. A conclusion is a summary of what you have learned from an experiment. In drawing your conclusion, you should
ask yourself whether the data supports your hypothesis. For example, if you found that your
experimental group produced 40 flowers and your control group produced 20 flowers, you
could draw the conclusion that the fertilizer increased the number of flowers produced and
your hypothesis is correct.
REVIEW
WHAT ARE THE 6 STEPS OF THE SCIENTIFIC METHOD?
1. Identify the Problem
2. Form a Hypothesis
3. Design an Experiment
4. Perform an Experiment
5. Analyze the Data
6. Communicate the Results
VOCABULARY

Observation– the process of using the five senses to gather information.

Hypothesis- a possible explanation for a set of observations or an answer to a
scientific question. Written as an “If… then…” statement.

Procedure- a step-by-step explanation of how to conduct an experiment.

Variable– a factor that changes in an experiment.

Independent Variable- the variable that is tested and changed by the scientist.

Dependent Variable- the variable that is measured by the scientist and changes
as a result of the independent variable.

Controlled Variable- the variables that are kept the same (constant) throughout
the entire experiment.

Controlled Experiment– an experiment that compares two or more things but
only changes one variable.

Data- the facts, figures, and other evidence gathered through observations.

Data Analysis- the process of interpreting the meaning of the data collected in
an experiment, finding patterns in the data, and thinking about what the patterns
mean.

Pattern– a similarity, difference, trend, or other relationship found in data.

Conclusion– a summary of what has been learned from an experiment and how
the data relates to the hypothesis.
Across
1. A possible explanation for a set of observations or an answer to a scientific question.
5. The variable that is measured by the scientist and changes as a result of the independent variable.
7. The variables that are kept the same (constant) throughout the entire experiment.
8. The step of the scientific method that involves creating a list of materials and writing a procedure.
9. The process of interpreting the meaning of the data collected in an experiment, finding patterns in the
data, and thinking about what the patterns mean.
11. The variable that is tested and changed by the scientist.
12. A summary of what has been learned from an experiment and how the data relates to the hypothesis.
13. A similarity, difference, trend, or other relationship found in data.
14. The process of using the five senses to gather information.
Down
2. The step of the scientific method that involves forming a scientific question to test.
3. The step of the scientific method that involves collecting data, creating a table and drawing a graph.
4. A factor that changes in an experiment.
6. A step-by-step explanation of how to conduct an experiment.
10. The facts, figures, and other evidence gathered through observations.
IDENTIFYING SCIENTIFIC QUESTIONS
So what is the most important distinction between a scientific question and a non-scientific
question? Evidence. The evidence must be measurable and repeatable. These questions
cannot be about personal opinion or judgment. Evidence to answer scientific questions is
gathered using the scientific method and carefully organized in a controlled experiment.
Scientists make observations and inferences about their scientific question and use
evidence to support their answers.
Directions: Below are several questions. In the spaces provided below each
question, explain if it is a scientific question or not. If it is a scientific question, explain
what types of measureable evidence you could collect in order to answer it. If it is not
a scientific question, then explain why.
Question #1: What is the optimal cooking time to make microwave popcorn?
Question #2: Which is the best type of microwave popcorn?
Question #3: What conditions will make the fluffiest popcorn?
Question #4: Why do people love popcorn so much?
IDENTIFYING VARIABLES
It is important to identify the variables in any experiment. You want to have as few variables
as possible when conducting your experiment, but you will always have three types of
variables: independent, dependent, and controlled. The independent variable is WHAT YOU
CHANGE ON PURPOSE IN AN EXPERIMENT. The dependent variable is WHAT YOU
MEASURE IN AN EXPERIMENT. The controlled variables are all the other factors that are
KEPT THE SAME.
Directions: Identify the independent, dependent and controlled variables in
each of the example experiments below.
1. Steven is testing different energy drinks. He wants to see which drink helps him
have energy all day. For one week, he drinks one 8 oz. can of a different energy
drink each morning.
Independent variable: ______________________________________________
Dependent variable: _______________________________________________
Controlled variables: _______________________________________________
2. Kendra wants to see if water, milk or vinegar will heat the fastest when placed on
a stove. She puts one cup of each liquid in a sauce pan and turns the heat on low.
Using a thermometer, he records the temperatures of each liquid after two
minutes on the stove.
Independent variable: ______________________________________________
Dependent variable: _______________________________________________
Controlled variables:
_______________________________________________
3. Jack fell off his bike and scrapped both of his knees. He decides to put ointment
and a band-aid on one knee and just a band-aid (no ointment) on the other knee
to see which knee heals faster.
Independent variable: ______________________________________________
Dependent variable: _______________________________________________
Controlled variables: _______________________________________________
4. Ryan is very tired when he wakes up for school every morning. He thinks it is
because he stays up late playing video games at night. He decides to go to bed
two hours early every night for a week to see if that makes him feel less tired.
Independent variable: ______________________________________________
Dependent variable:
Controlled variables:
_______________________________________________
_______________________________________________
WRITING SCIENTIFIC QUESTIONS & HYPOTHESES
A scientific question should include your independent variable and dependent variable.
These questions usually reflect a cause/effect relationship, and should never have a yes or
no answer.
How does (independent variable) affect (dependent variable)?
How is (independent variable) related to (dependent variable)?
What causes (independent variable) to (dependent variable)?
What is the effect of (independent variable) on (dependent variable)?
A hypothesis should be written in the form of an “If… then…” statement. It should include
your independent and dependent variables.
If ____(independent variable)________, then _____(dependent variable)___________.
Directions: Use one of the question starters above to write a scientific question
about each topic. Then write a hypothesis as an “If … then…” statement. Make sure to
include the independent and independent variables in both.
Example: You are eating a hot dog and accidently spill mustard on your white
shirt. You ask your mom what to do and she says to use bleach. You wonder
if bleach is the best stain remover is to use.
Independent variable: using bleach
Dependent variable: how well the mustard stain is removed
Question: What is the effect of bleach on the removal of a mustard stain?
Hypothesis: If I use bleach on my shirt, then it will remove the stain.
1. You notice that Jenny scores 100% on her vocabulary test every week. When you
ask her how she does it, she tells you that she uses flashcards. You wonder if using
flashcards would work for you.
Independent variable: _________________________________________________
Dependent variable: __________________________________________________
Question: ___________________________________________________________
____________________________________________________________________
Hypothesis: _________________________________________________________
____________________________________________________________________
2. You see Jose making many more basketball goals than you are able to. He always
bends his knees to make the shot, but you don’t. You want to know if bending your
knees is really that important.
Independent variable: _________________________________________________
Dependent variable: __________________________________________________
Question: ___________________________________________________________
____________________________________________________________________
Hypothesis: _________________________________________________________
____________________________________________________________________
3. You accidently leave a glass of milk in your room for several days. When you
remember it, you see that it has turned mushy and sour. You wonder how long it
took for the milk to become like that.
Independent variable: _________________________________________________
Dependent variable: __________________________________________________
Question: ___________________________________________________________
____________________________________________________________________
Hypothesis: _________________________________________________________
____________________________________________________________________
4. You buy chocolate chip cookies at the grocery store. When you eat them, you
notice that some cookies have more chocolate chips than others. You are curious
about how that happens at the cookie factory.
Independent variable: _________________________________________________
Dependent variable: __________________________________________________
Question: ___________________________________________________________
____________________________________________________________________
Hypothesis: _________________________________________________________
____________________________________________________________________
WRITING A PROCEDURE
Once a problem has been observed and a hypothesis suggested, the next step in the
scientific method is to design an experiment that will either prove or disprove the
hypothesis. Experiments will be repeated many times by other scientists. When scientists
publish their work, they expect that it will be repeated and verified by other scientists in
their field of study. Scientists must be able to write clear descriptions of the steps of their
experiment so that others may be able to follow and repeat it.
Directions: Build a unique structure out of the blocks provided by your teacher.
Write a set of instructions (procedure) that provide clear directions for how to build
your structure. You must be exact and precise. As you are writing your instructions
consider whether the instructions are clear enough for others to follow. Write your
instructions in a stepwise fashion.
For example:
Step 1. Place the red square on the table to provide a base.
Step 2. Take the blue triangle and……
Once your directions have been completed, swap instructions with another person.
Read the directions from the other person and try to build their structure using their
building materials. When both of you have finished building, compare your original
structures to the replicated structures. Then answer the analysis questions below.
Analysis Questions:
1. Were your instructions written clearly enough for the other person to follow?
2. How close was the other person in replicating your structure?
3. Identify the step of your instructions that you feel was the most unclear and
rewrite that step.
4. Why is it important that scientists write procedures that can be reproduced or
replicated?
Procedure: (don’t forget to number your steps)
CREATING TABLES
Tables are a way for scientists to organize data they have collected during an
experiment and be able to analyze it quickly and accurately. Data is arranged in such a way
that it makes it easier for people to see and understand.





Each table should have a title to say what type of information the table is showing.
The first column in a table lists the independent variable (what the scientist changed).
The second column in a table lists the dependent variable (what is being measured).
Units of measurement are listed next to the variable.
Within the grid of the table, the collected data is recorded.
Example: Students of different ages were given the same puzzle to assemble. The
assembly time was measured.
Student Ages Assembly Time (minutes)
5
20 minutes
6
15 minutes
7
12 minutes
8
10 minutes
9
8 minutes
Directions: Use the notes above to help you give the table a title and properly
label the columns and rows based on the given experiment.
1. Two groups of students were tested to compare their speed working math
problems. Each group was given the same problems. One group used calculators
and the other group computed without calculators.
Title: _____________________________________________________
With calculators
2 questions per minute
Without calculators
1 question per minute
2. Three different brands of paper towels are tested to see how much liquid they are
able to absorb. Each paper towel is cut to a size of 225 cm2.
Title: __________________________________________________________
Bounty Paper Towels
220 mL
Viva Paper Towels
230 mL
Brawny Paper Towels
200 mL
3. Four different cars are tested to see which one gets the best gas mileage on the
highway. Each car traveled 20 miles at 60 miles per hour.
Title: __________________________________________________________
Toyota Camry
35 mpg
Honda Accord
36 mpg
Chevrolet Malibu
36 mpg
Ford Fusion
37 mpg
4. Five students want to know if the amount of time spent studying affects their test
scores. Student 1 studied for 30 minutes and earned a 75%. Student 2 studied for 1
hour and earned a 79%. Student 3 studied for 1 hour and 30 minutes and earned an
84%. Student 4 studied for 2 hours and earned a 90%. Student 5 studied for 3 hours
and earned a 100%. Draw a table below that represents all of the data. Make sure to
include a title, column labels, all of the students and their scores.
Title: __________________________________________________________
CREATING GRAPHS
Graphs are a way for people to see the data you have collected during an experiment
and be able to analyze it quickly and accurately. Looking at a graph can help you find
trends in the data.




Each graph should have a title to show the relationship between the independent and
dependent variable.
The axes are labeled correctly: independent variable on x-axis (bottom), dependent
variable on y-axis (side).
The number scales on the x-axis and y-axis are in equal increments and start at 0.
Your data is graphed correctly.
Example: Students of different ages were given the
same puzzle to assemble. The assembly time was
measured.
Directions: Use the notes above to help you properly label and draw the graph
below based on the given table.
Activity
1) A survey of students' favorite after-school
activities was conducted at a school. The
table below shows the results of this survey.


# of Students
45
Visit With Friends
99
Earn Money
44
School Clubs
22


Play Sports
Do you have:
Graph Title
X-axis Title & Scale
Y-axis Title & Scale
All data plotted
2. Three different brands of paper towels are tested to
see how much liquid they are able to absorb. Each
paper towel is cut to a size of 225 cm2.




Brand of Paper Amount of Liquid
Towels
Absorbed (mL)
Bounty Paper
Towels
220 mL
Viva Paper Towels
230 mL
Brawny Paper
Towels
200 mL
Do you have:
Graph Title
X-axis Title & Scale
Y-axis Title & Scale
All data plotted
2. Four different cars are tested to see which one gets
Car
the best gas mileage on the highway. Each car
Toyota Camry
traveled 20 miles at 60 miles per hour.




Gas mileage
35 mpg
Honda Accord
36 mpg
Chevrolet Malibu
36 mpg
Ford Fusion
37 mpg
Do you have:
Graph Title
X-axis Title & Scale
Y-axis Title & Scale
All data plotted
WRITING AN ANALYSIS AND CONCLUSION
When writing an analysis, you must summarize and explain the results of the experiment.
For example: When looking at how the amount of time studying affects test scores, I found
student 1 studied for 30 minutes and earned a 75%. Student 2 studied for 1 hour and earned
a 79%. Student 3 studied for 1 hour and 30 minutes and earned an 84%. Student 4 studied for
2 hours and earned a 90%. Student 5 studied for 3 hours and earned a 100%. The more time
spent studying resulted in higher test scores. When students study longer, it gives them more
time to remember and understand the information.
When writing a conclusion, restate your hypothesis, state whether it was correct or
incorrect, and explain why using evidence.
For example: My hypothesis was, “If you spend more time studying, then your test scores will
be higher.” My hypothesis was correct, because Student 1 studied for the least amount of time
and got the lowest test score. Student 5 studied for the most amount of time and got the
highest score.
Directions: Use the data from your Testing a Variable: Whirlybird Size lab and the
notes above to help you write an analysis and conclusion for the lab.
1) Write an analysis of your data.
2) Write a conclusion for the experiment.