1
Complete these notes as discussed in class to review the 6 steps.
STEP 1: Scientists ask
their surroundings.
STEP 2: Take an educated
based on
from
about what you think the
is to your question.
STEP 3: Set up an experiment to
your question.
STEP 4: Look at your
about your question.
and decide what they tell you
STEP 5: Decide what the
• Ask was my
to your question is.
right or wrong?
STEP 6: Ask if you need to do the experiment
to find out more.
• What’s
question I can ask related to this
topic?
Number the steps of the scientific method in order.
Step 1 ______
A. Ask a Question
Step 2 ______
B. Analyze Your Results
Step 3 ______
C. Test your hypothesis
Step 4 _____
D. Form a Conclusion
Step 5 _____
E. Form a Hypothesis
Step 6 _____
F. Ask another question
2
The Mystery of the Footprints
Use the footprint images from class to first write your observations and then make your inferences.
Observations (what you see)
Inferences (what you think)
Box
1
Box
2
Box
3
The Mystery of the Footprints – Short Story
3
Observations & Inferences Practice
Read the following observations – then make inferences that explain each
observation. Remember, there may be more than one logical explanation for each
observation!
Observation 1: You observe that the sky at noon is darkening
You inference:
__________________________________________________________________
__________________________________________________________________
Observation 2: Your principal interrupts class and calls a student from the
room
Your inference:
__________________________________________________________________
__________________________________________________________________
Observation 3: All middle school students are bringing lunch from home.
Your inference:
__________________________________________________________________
__________________________________________________________________
Observation 4: You hear a siren going past the school.
Your inference:
__________________________________________________________________
__________________________________________________________________
Observation 5: You leave the movie theater and observe that the street is wet.
Your inference:
__________________________________________________________________
__________________________________________________________________
4
1. Ask about
, organisms, and events in the
2. Can be answered through
or surveys
world
that involve experiments,
,
3. Are answered by collecting and analyzing evidence that is
4. Relate to scientific ideas rather than
or
5. Do not relate to the
or to
phenomena
Examples of Testable Questions
The key difference between a non-testable and a testable question is that testable questions are
always about changing one variable to see what the effect is on another variable.
Non-Testable Questions
Testable Questions
(lead to science reports)
(lead to investigations)

How do plants grow?


What makes something sink or float?
How do rockets work?



How does the sun heat up water?
How does changing the amount of water
affect the growth of tomatoes?
How does changing the type of soil affect
the growth of petunias?
How does changing the amount of sunlight
affect the growth of daffodils?
How does changing the type of fruit affect
its ability to float in water?
How does changing the shape of a rocket’s
fins affect its ability to fly?
How does changing the type of water affect
its ability to absorb thermal energy from
the Sun?
Write a testable question that uses some of the supplies on
your desk.
5
1. are any of the factors that could
2. only
may be
in a scientific investigation
factor is changed or manipulated at a time but one or more factors
during an experiment
3. all other factors remain
(the same) throughout the study
1. the factor that stands
and
because of what you are trying to measure
2. the factor
wish to test and that
manipulate or
3. in a testable question, is found after the words
4. in a hypothesis, is found after the word
1. the factor you
to gather results
2. the factor that changes as a result of what
in the experiment
3. in a testable question, is found after the word
4. in a hypothesis, is found after the word
Testable Question
How does changing the amount of time you heat a
cup of water affect how the amount of sugar that
dissolves in it?
How does changing the size of the openings in a
faucet affect the amount of water that flows through
it?
How does changing the amount of time a candle is
burned affect its height?
How does changing the age of a person affect the
amount of time they listen to music?
Independent Variable
(What I change)
Dependent Variable
(What I measured)
____________________________
water is heated
Amount of __________________
dissolved
Water faucet _________________
_________________________
(closed, half open, fully open)
Amount of __________________ that
flows through opening
_____________________________
candle is burned
Height of ___________________
___________________________of
people listening to music
Amount of __________________
music is listened to
6
Look back at your original testable question.
1. What should the independent variable be in your experiment?
2. What should the dependent variable be in your experiment?
3. Re-write your testable question, using the sentence format,
“How does changing the independent variable affect the
dependent variable?
How does changing the
affect the
Testable Questions, Independent & Dependent Practice
Let’s make sure you know how to write a testable question using independent & dependent
variables. Remember your sentence structure!
1) I wonder if the number of books I read will help me get smarter.
Independent Variable
Dependent Variable
Testable Question
2) I wonder what will happen to my plant if I leave it in the closet with no light.
Independent Variable
Dependent Variable
Testable Question
3. I wonder if I watch movies with a lot of swearing in it, I will start swearing more.
Independent Variable
Dependent Variable
Testable Question
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1. comes from
or prior knowledge
2. is a
that tells the answer to a question
3. Does not use
such as I, we, or you.
4. uses the format,

If the independent variable changes this way, then the dependent variable will
change this other way because your reasoning.
Poor Hypotheses
Good Hypotheses
If I put my fingers in different water then they
will wrinkle at different times.
If fingers are put in warm water and then cold
water, then the fingers in the warm water will
wrinkle faster, because the warm water will
dissolve the oils on the skin faster and then the
fingers will begin to absorb the warm water
more quickly.
If pea plants are grown in 3 different types of
soil (sand, clay, and top soil), then the plants
growing in the top soil will grow the tallest,
because it contains the most nitrogen which is
a nutrient required for plant growth.
If I grow plants then the best growing plant
will be the one that gets the most food.
Write a hypothesis for your testable question. Be sure to you the “If the independent
variable changes this way, then the dependent variable will change this other way because your
reasoning” sentence structure. Try using the words “increase” and “decrease” as you describe
how the independent and dependent variables will change.
8
Experimental Design Practice
Use the following statements to practice good experimental design.
1) Chocolate may cause pimples.
Testable Question:
Independent Variable:
Dependent Variable:
Hypothesis:
2) Temperature may cause leaves to change color.
Testable Question:
Independent Variable:
Dependent Variable:
Hypothesis:
9
A Variable Way to Practice Variables Assignment - 25 points
Variables are basically something that changes in the experiment.
A Quick Recap… use your notes to quickly define these four term.
Testable Question:
Independent Variable:
Dependent Variable:
Hypothesis:
First, read the following hypotheses and identify the different variables.
1) If you increase the number of cigarettes you smoke, then you will increase your risk for lung
cancer because cigarettes have chemicals in them that have been known to cause cancer.
a. Independent : ________________________________________________
b. Dependent: __________________________________________________
2) If you increase the amount of blood in the water, then you will increase the number of sharks
in the area because sharks think the blood is from a wounded animal that they want to eat.
a. Independent : ________________________________________________
b. Dependent: __________________________________________________
3) If you increase the amount of milk you drink, then you will increase the strength of your
bones because milk has calcium in it and calcium has been proved to fortify bones.
a. Independent : ________________________________________________
b. Dependent: __________________________________________________
4) If you increase the number of hours you spend in practice, then you will increase the number
of free throw shots you will make because the more time you practice the better your muscles
will remember what to do when you go to the free throw line.
a. Independent : ________________________________________________
b. Dependent: __________________________________________________
10
Next, in this section, you will read about 2 experiments that I am performing.
Please help me write a testable question, a hypothesis and help me identify the
different variables. – independent and dependent.
5. I am doing a test to see if there is a connection between how long you run and how fast your
heart beats. I will be performing an experiment where a person will run for a 1 minute and I
will check their heartbeat. Then they will run for 2 minutes and I will check their heart rate. I
will do this up to 6 minutes and see if there is a connection. What do you think my
hypothesis should be? What are my variables?
Testable Question:
Independent variable: __________________________________________________________________
Dependent Variable: ___________________________________________________________________
Hypothesis:___________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
6. Volleyball season is right around the corner and I think I need to make sure I am healthy and I
want to lose some weight. I keep seeing these commercials for Special K cereal and if you eat
it for 2 weeks, you will lose 10 pounds. I want to test this idea and see if it actually works. I
plan on eating whatever I want for the next two weeks and am going to track my weight every
morning. Then I will eat nothing but Special K cereal, milk and water for two weeks and track
my weight in the morning. What do you think my hypothesis should be? What will my
variables be?
Testable Question:
Independent variable: __________________________________________________________________
Dependent Variable: ___________________________________________________________________
Hypothesis:___________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
11
1. except for the independent and the dependent variables, every other factor in the
experiments
2. are all of the factors that
3. are often
across all of the groups you are comparing
, temperatures,
, and materials
Testable Question
Constant Variables
(What I keep the same)
How does changing the amount of time you heat a cup of
water affect how the amount of sugar that dissolves in it?



____________________________
____________________________
____________________________
How does changing the size of the openings in a faucet
affect the amount of water that flows through it?



___________________________
___________________________
__________________________



___________________________



___________________________
___________________________
___________________________
How does changing the amount of time a candle is burned
affect its height?
How does changing the age of a person affect the amount of
time they listen to music?
___________________________
___________________________
Looking at your testable question and hypothesis, list 5-8 the constant
variables you would need in an experiment to test your question.
1.
2.
3.
4.
5.
6.
7.
8.
12
1. part of the experiment _________________________ from the rest of the experiment
where the independent variable being tested _______________ influence the results
2. __________ changes are done to this object in the experiment by the scientist
3. is used to compare the ____________________ against
4. not all experiments need a control
5. Example: How does changing the amount of medicine you give a patient affect how fast
they recover from the flu?

The experimental control would be the patient given _______________ medicine.
13
More Experimental Design Practice
1. “I want to see if different colors of light help plants grow better. I am going to take four plants
(all the same type) and set them up underneath different lights. One will be a white light, one will
be red, one will be blue, and one will be green. Every day, I will water them the same amount at the
same time. I will also record how high each plant grows for two weeks and then look at my results.”
Write a testable question.
What is the independent variable? __________________________________________
What is the dependent variable? ____________________________________________
Write a hypothesis.
What are the constant variables?
1. ______________________________________
2. ______________________________________
3. ______________________________________
What is the control? ____________________________________________________
2.“I want to see how taping my thumbs will affect my time it takes to button up a shirt. I will test
the same person – they will do three trials buttoning up the same shirt with their thumbs taped to
their palms. Then I will do three trials where their thumbs are not taped up. I will average the time
in seconds that it takes to button up and shirt with their thumbs taped and without their thumbs
taped.”
Write a testable question.
What is the independent variable? __________________________________________
What is the dependent variable? ____________________________________________
14
Write a hypothesis.
What are the constant variables?
1. ______________________________________
2. ______________________________________
3. ______________________________________
What is the control? ____________________________________________________
3. “I want to see if there if drinking a lot of milk will affect how much you eat at dinner. I will
take 5 people. For three days, I will give them two glasses of milk to drink before they eat dinner. I
will serve the same food for those three days and they will eat at the same time every day. After
three days of drinking milk, I will then have the people eat for three days without drinking milk
before they eat dinner (again, same food, same time). I will measure how much food they eat in the
three days that they drink milk and the three days that they don’t drink milk and compare my
results.”
Write a testable question.
What is the independent variable? __________________________________________
What is the dependent variable? ____________________________________________
Write a hypothesis.
What are the constant variables?
1. ______________________________________
2. ______________________________________
3. ______________________________________
What is the control? ____________________________________________________
15
Experimental Design Review - 50 points
Mrs. Smith’s science classes have all been working hard on their science experiments to help
understand the different parts of the Scientific Method and experiments. One day, Ryan and
Mike are testing the effect of an unknown chemical on the memory of their classmates.
SUDDENLY, the large beaker with the unknown chemical is knocked over by Ian, who was on
his way to the pencil sharpener. The chemical spills everywhere in front of Mrs. Smith’s desk,
and although Alex tries to save her, Mrs. Smith collapses to the floor in a fainting spell. When
she is finally revived, Mrs. Smith can’t remember anything about experimental design,
hypotheses or variables! She can only remember that everyone needs to pick their papers up
when they come in the classroom. Please help fill out this worksheet so that you can teach Mrs.
Smith how to come up with hypotheses, identify variables and figure out a conclusion from
certain data. Please help her!!!!
Part 1: Review
In this worksheet, you will be practicing your science skills. The first problems help you with writing a
hypothesis. Remember – a hypothesis is an _________________ ____________ . When writing a
hypothesis, you need to make sure that it starts with _____ . After this, you put something about the
variable that you control, which is the ____________________________ variable. That is the first part of
your hypothesis. The second part starts with _________ . After this, you write something about the
variable that depends on the first variable – this is the _____________________ variable. It will change
because you are changing the first variable. The final part of the hypothesis begins with
Presto, the perfect recipe for an awesome hypothesis. Also, remember – a constant is something that
stays the __________ in an experiment. And, the ___________________ is the group that we don’t
change in order to compare results from the group we are testing.
Part 2 : Identifying Variables
You are given a hypothesis – you need to identify the independent and dependent variables in each
question.
1) If the amount of sugar added to water is increased, then the amount of hummingbirds
attracted to the water will increase because hummingbirds like to eat sweet nectar.
Independent Variable:
_______________________________________________________
Dependent Variable:
________________________________________________________
2) If the depth of Lake Erie increases, then the temperature will decrease because of convection.
Independent Variable:
______________________________________________________
Dependent Variable:
________________________________________________________
16
3) If the amount of snow increases on the roads, then the amount of school buses able to pick up
students will decrease because the roads will be impassible due to the snow.
Independent Variable:
_______________________________________________________
Dependent Variable:
________________________________________________________
Part 3: Writing a hypothesis
You are given the independent variable and the dependent variable. Please use this information to write a
hypothesis. Remember – you need to write it in an “If, then, because ” statement.
1) Independent Variable: The number of recycling posters.
Dependent Variable: The total number of cans being recycled.
2) Independent Variable: Number of light bulbs on a front porch.
Dependent Variable: Number of bugs at night on the porch.
3) Independent Variable: Temperature of the refrigerator
Dependent Variable: Amount of rotten food
17
Part 4: Using an experimental example to write a hypothesis and identify the variables
1) Kelsie wanted to see if caffeine helped improve how her friends did on their science test.
After making sure that they all studied the same amount, she gave Alex, Alexis, and Chelsea
three Cokes a half hour before their test. She took Madison, Mary, and Calynn and let them
take their science test with no caffeine at all. They all took the test at the same time and in the
same room.
Hypothesis: ________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Independent Variable: _____________________________________________
Dependent Variable: _______________________________________________
2) Patrick decided to test if wearing red increased his chances of getting a date for the football
game. He wore all red clothing on Monday and Tuesday and then wore just jeans and a white
T-shirt on Wednesday and Thursday. Each day, he asked out three different girls (at different
times) with the same pickup line and the same place in the hallway.
Hypothesis: ________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Independent Variable: _____________________________________________
Dependent Variable: _______________________________________________
Part 5: Understanding the results and reaching a conclusion
1) From the previous experiment, Kelsie found that Alex, Alexis and Chelsea all flunked their
science test. Madison, Mary and Calynn all got an A on their science test.
What should Kayla’s conclusion be?
________________________________________________________________________
________________________________________________________________________
What girls were the control group in Kelsie’s experiment? (circle the correct group)
Alex, Alexis, Chelsea
or
Madison, Mary, Calynn
What was one constant in Kelsie’s experiment? _______
A. What the girls wore
B. How many times the girls answered a question wrong
C. The amount that each girl studied
D. Where the girls sat in the room
18
What are TWO other constants from Kelsie’s experiment?
1) ________________________________________________________
2) ________________________________________________________
2) Patrick found that more girls said yes when he asked them to the football game when he was
wearing all red clothing. He got 5 dates while wearing red and only one in a jeans and T-shirt.
What should Patrick’s conclusion be?
_______________________________________________________________________
________________________________________________________________________
What days were his “control group” days? (circle one)
Monday/Tuesday
Wednesday/Thursday
What were the two constants in his experiment?
1) _____________________________________________________
2) _____________________________________________________
Looking at Patrick’s experiment, what do you think are some other variables that
could have affected his results? Meaning that red had nothing to do with Patrick
getting more dates on Monday and Tuesday – something else could have affected
Patrick’s luck. What do you think could have happened other than Patrick in red?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
_______________________________________________________________________