Getting Started
• Warm Up Handout
• Learning Goal handout.
– Take out the handout titled “Biology
Learning Goal Scientific Method”
• Notebook
Take My Word For It
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The Earth is the center of the universe.
The sun revolves around the Earth.
All matter is made up of 4 elements: fire, water, earth, & air.
Bowling balls fall faster than basketballs because they are heavier.
The Vietnam war was about preventing the spread of communism.
Hugo Chavez was a dictator.
High-fructose corn syrup is a safe alternative to sugar.
– So is saccharine, and Nutrasweet, and sucralose, and dextrose
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Sadaam Hussein had weapons of mass destruction.
Milk is just as safe today as it was 50 years ago.
GMO’s pose no threat to your health.
7-up is made with 100% “all natural” ingredients.
• What do all these have in common?
• Highly debated statements that have been delivered to people as fact.
Warm Up Discussion Answers
• The world was once thought to be flat.
Discuss with a partner the following
questions and answer:
1. Why did people believe this?
2. What caused some to not believe this?
3. What is it about people that causes
someone to reject popular thoughts?
4. Is this behavior good or bad for
society?
The Learning Objectives are here to identify the
main concepts you are to know by the end of
this lesson.
Using A Scientific Approach
• Learning Objectives:
– Define & describe the steps in the scientific
method.
The Performance Objectives are here to
identify the activity
you will do to ensure
– Explain the groups and variables
in a controlled
you know it & I can be sure you are working
experiment.
towards reaching a “3” on the learning
– Compare and contrast scientific
theories and
scale. You accomplish mastering the
scientific laws.
learning objectives by doing the
– Define & explain the importance
of models
in
performance
objectives.
science.
• Performance Objective:
– At the end of class you will have completed a flow
chart outlining the scientific method. Your job is to
know all the steps of the scientific method and be
able to identify these in varying scenarios as well as
be able to set up an experiment that utilizes all
these steps.
Using A Scientific Approach
• Vocabulary:
– Scientific method
– Observation
– Hypothesis
– Control group
– Experimental group
– Dependent variable
– Independent variable
– Scientific theory
– Scientific law
– Model
The Scientific
Method
• The Scientific Method is a step-by-step
approach to problem solving.
• Used correctly, the scientific method can
help you solve problems of all sorts, from
personal to physical.
Your 1st “Handout” (like I have on the
board). Fill it in as we go. Refer to
the back board…
Make a claim
Using A Scientific Approach
Empirical science is
attributed to Aristotle,
however Muslim
scientists in the 10th –
14th centuries (most
notably al-Haytham)
were the first ones to
use the basic approach
to problem solving.
• Scientific Method:
– It is an organized plan for gathering,
organizing, and communicating
For notes: Write
information
down the underlined
portion!
• The goal of scientific methodology is to
solve a problem or to better understand an
observed event.
• The strength of the method is that, if
done right, the solution is highly credible
as opposed to merely opinion.
Beginning a Scientific Investigation
• The 1st Step…
• Observation: is information that
you obtain through your senses.
– Observation is the act of
noting or perceiving objects
or events using the senses.
– Observation takes interest
and patience.
– It takes care but a desire to
know WHY?
What the…
Using A Scientific Approach
• Observations lead to questions.
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You see lightning in a storm.
You might wonder, “What temperature is it?”
An apple hits you in the head as you sit under it.
You ponder, “Why do apples fall?”
You can’t eat raw eggs so you cook them.
You ask, “Why do eggs become solid when they are
boiled?”
Soaps come in all colors.
But you notice, “Why does soap always lather white
even though it comes in a bunch of other colors?”
The genes for hair are all the same.
But you ask, “Why is some hair brown and other
hair red?”
You get a candy bar from the store.
You say, “Dang this chocolate's good! I wonder
why?”
Using A Scientific Approach
• Making observations leads to questions.
• The 2nd Step…
• Form a Hypothesis:
– A hypothesis is a possible answer to a
question that CAN BE SCIENTIFICALLY TESTED!
• In other words, A hypothesis is a prediction that
can be tested by observation or experimentation.
• A hypothesis is NOT JUST AN EDUCATED
GUESS!
– It is useful to make create a hypothesis as
an ‘if… then… because…’ statement.
Scientific Method: Hypothesis
• Hypothesis examples…
• Which is best?
– Chocolate is sweet b/c of sugar.
– Candy is sweet because it makes me
happy.
– If I take sugar out of a chocolate
recipe then the resulting candy will
not be as good because sugar makes
the chocolate good.
Examine the Hypothesis
• What are parts of a good hypothesis?…
If I take sugar
Some thing that’s tested
out of a
chocolate recipe
Compared to something
then the
that’s known
resulting candy
The prediction
will not be as
good because
The measurable outcome
sugar makes the
chocolate good.
Using A Scientific Approach
• The 3rd Step…
• Design & Conduct a Controlled Experiment:
• A controlled experiment is one that is
designed so that only one variable is changed
at a time.
– What is a variable?
• It’s a factor or value that can change or has multiple
values.
• Experiments come in all shapes & sizes:
– Trials, taste tests, competitions, simulations,
Using A Scientific Approach
• Good Experiments have TWO Groups
• Group #1
• Control Group:
– This group has expected results
– This group is the predictable standard
– Ex. Chocolate candy bar made from the original
recipe…you know how the chocolate is going to
taste.
Using A Scientific Approach
• Group #2
• Experimental Group:
– This group has the ONE and only ONE variable
changed (related to the hypothesis) to cause a
measurable change different from the control
group.
– Ex. Chocolate that has been made w/out sugar…you
aren’t really sure how the chocolate is going to
taste but you’re pretty sure
Controls
• A CONTROL can be challenging to figure out.
• The thing to remember about controls is that
they need to exist for comparison purposes.
• If your experiment is testing one thing
changing, like the chocolate recipe, this is
easy to decide.
• When you are comparing several unknowns,
this can be a little more difficult to decide…
The Variables
• The thing that is being tested in an
experiment is called the independent
variable.
– This is sometimes called the manipulated
variable.
– A special aspect of the scientific method is
that one controlled experiment has only 1
independent variable.
– Remember, the independent variable is the
ONE thing being tested in an experiment.
Using A Scientific Approach
• On experimentation variables…
– Experiments have variables.
– Independent Variables (aka manipulated variables) are
changes that are directly caused by the experimenter
(you.)
• Ex. Amount of sugar added to candy
• This is the thing that is stated in the hypothesis.
• It will generate data = dependent variables.
– Dependent Variables (aka responding variables) are
changes that occur due to independent variables.
• These are the values that can be measured!
• Ex. Candy is not as good b/c of lack of sugar
Identify The Control
• Hypothesis: If I feed a fish four times a day
it will grow bigger than a fish fed twice a day
because food causes organisms to grow.
• Experiment: One tank of gold fish is fed the
normal amount of food once a day, a second tank
is fed twice a day, and a third tank four times a
day during a six week study. The fish’s weight is
recorded daily.
• What is the control?
• The fish that’s fed once a day.
• Why? This is the baseline measurement.
Everything else compared to this would be a
change.
• What would be the independent & dependent
variables?
Identify Control Group
Hypothesis: If we use broadleaf weed killer, then the dandelions will die.
• Experimental Control:
– You have two flower beds that are exactly the same, they both contain the same
type of dandelion, a broadleaf weed.
– The bed on the left is watered everyday.
– The bed on the right is watered everyday and sprayed with weed killer everyday.
• This is the one thing that’s changed.
– Eventually the dandelion in the bed on the right dies.
– Which bed of flowers is the control group? 1 minute with partner.
Both
Watered normally
Same Soil
Same Sunlight
Weed Killer Added
This is the only thing
different
Using A Scientific Approach
• The Payoff For Having 2 Groups
• The essential part of good scientific
investigation lies in the comparison between
the 2 groups.
• The differences between the two gives data
that is used to defend claims.
Control
Group
Compare
Experimental
Group
Compare
Control
Group
Experimental
Group
Expected
Results
Experimental
Results
The difference between the
two = evidence that is used
to defend claims!
Identify Control Group
Hypothesis: If we use broadleaf weed killer, then
the dandelions will die.
• Experimental Control:
– Why this becomes a good experiment is because there
is only 1 variable changed, the weed killer.
Both
Watered normally
Same Soil
Same Sunlight
Weed Killer Added
This is the only thing
different
Which is the Control,
Which is the Experimental?
Kisses Batch #1, Normal
Kisses Batch #2, No Sugar
What is the Independent Variable?
What will be the Dependent Variable?
What difference do we hope to get?
1 minute
with partner
Using A Scientific Approach
• What would be a good test for my
chocolate hypothesis?
• In this case we could make a few
batches of chocolate and have people
taste test it.
Using A Scientific Approach
• The 4th Step:
• Data is created & analyzed to draw
conclusions.
– You will need to take a look at data to make
a decision on what it tells you.
Using A Scientific Approach
• Gathering Data
• In the case of all experiments, the most
important step is to gather reliable data.
– Data is any information from your experiment
that you collect.
• Can be numbers or polls or other.
• Quantitative = Numbers
• Qualitative = Descriptions
Data
• There are several aspect of data that
must be taken into account:
– It must be accurate & precise as possible.
– There must be enough data. (“In Triplicate”)
• In this example, there will be 3 trials ran.
– It must not be biased.
• = shouldn’t be employed or paid by Hershey
– It must be neat.
Using A Scientific Approach
• What does the data tell you?
• For our example with the chocolate we
will gather tables of the preference
between the control and experimental
groups.
• If we have taken enough reliable,
accurate, unbiased data then we should
be able to make a decision.
Chocolate Taste Tests
Decision: does our data support our hypothesis?
Which chocolate is sweeter
Poll opinion # Votes
– If I take sugar out of a chocolate recipe then the resulting candy will
not be as good because sugar makes the chocolate good.
Trial Data: out of 100
A
B
Trial 1
95
5
Trial 2
75
25
Trial 3
85
15
A = Sugar
B = No Sugar
Chocolate A B
Trial
1
A B
2
A B
3
Using A Scientific Approach
• Drawing Conclusions:
• When drawing a conclusion we must consider the
hypothesis. What was the hypothesis?
– If I remove Sugar from a recipe then it will not be as good.
• If your conclusion supports the hypothesis then you
have performed one good experiment.
– You could compare with similar tests, run another test, or
repeat the same test over to be sure.
• If you conclusions do not support the hypothesis then
you must revise your experiment and test a new
variable.
– How would this happen?
– Maybe cocoa actually is the sweetening agent.
Using A Scientific Approach
• Usually one experiment isn’t enough to
draw a definitive conclusion so multiple
trials should be ran with the same
experiment.
– In our case we should run several trials,
repeating the experiment exactly with
different polls.
– The data should be illustrated in a graph to
help interpret the results.
BREAK DOWN THE STEPS…
What are the two groups in the experiment?
Control Group
Predictable standard = the group where
you expect the results!
Experimental Group
Exactly the same as the control group
except for one thing…the independent
variable.
You measure the
dependent variables in
the experiment.
What Could Happen:
Option 1: the data doesn’t
support the hypothesis.
What Could Happen:
Option 1: the data does
support the hypothesis.
After the Conclusion
• The Last Step… options here.
• After validating a hypothesis several times
you can come to a conclusion.
• This is also called “making a claim”.
– In our case we could claim that sugar makes
chocolate sweet.
• But one study usually isn’t enough.
• A good scientist will retest multiple times
testing a variety of similar hypotheses.
Make A Claim
Developing a Theory:
• After validating many similar
hypotheses you then come up with a
theory that explains the result of your
experiments.
• A scientific theory is a well tested
explanation for a set of observations or
experimental results.
Make a claim
Scientific Theories
• One drawback to theories is that
scientific theories are never completely
proven.
• Ex: The theory of relativity
• Ex: The theory of evolution
• Ex: The theory that chocolate is the
best candy on Earth.
Using A Scientific Approach
• Scientific laws
– Scientific laws are patterns in nature that
don’t need to be proven.
– summarizes an observed pattern found in
nature without needing to explain it
anymore (it’s a constant – like death and
taxes). The explanation of such a pattern is
provided by many scientific theories.
– Law of Gravity - Newton
– Law of Thermodynamics - Hess
– Law of Electricity - Ohm
– Conservation of mass - Lavoisier
CheckPoint
Describe what the difference is between
scientific hypotheses, theories, & laws.
• Hypotheses are narrow
– They are reasonable predictions to answer
questions for observed singular events
• Theory is a well tested explanation for
patterns observed in nature based upon many
related hypotheses.
– Theory of evolution = change happens over time
• A law describes patterns in nature
– A law doesn't need testing or validation anymore
– The law of gravity.
Scientific Models
• After you prove a law, make a claim, or develop a
theory, you should make a model to represent the
concept.
• What is a Model?
• Scientific models are physical or mental
representation of an object or an event
• What is the Purpose of a Scientific Model?
• Models make it easier to understand things that are
very complex, very large, very small or difficult to
observe directly.
– By illustrating the theory/law/phenomenon in 2- or 3-D
Make a claim
Model
Scientific Models
• Example: When
designing a new airplane
the designer will often
make a computer model
demonstrating how the
airplane should handle
air current.
• What would be a model
for:
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The solar system?
The earth’s rotation?
Water cycle?
An atom?
Macroeconomics? Just
kidding….
Scientific Models
Overview
Make a claim
Model
Practice
1.
2.
3.
4.
5.
6.
7.
Put the steps below in order…
Analyze the data
Create a hypothesis
Draw conclusions
Perform the experiment
Observe the phenomenon.
Collect the data
Do some background
research.
8. Ask questions.
9. Design a controlled
experiment.
10. Make a claim.
5. Observe
8. Ask questions
7. Do some research
2. Create hypothesis
9. Design experiment
4. Experiment
6. Collect data
1. Analyze data
3. Draw conclusions
10. Make a claim
Conclusion
• Questions…
• On your warm-up page, grade your
learning score & state at least one thing
you learned…
• How do you feel you progressed?
• Show me with fingers.
On the topic of OBSERVATIONS: Be careful, objects can be
confusing and individual objects are really dependent upon their
surroundings and your perspective.…
YOUR EYES ARE STUPID:
http://youtu.be/dJyvcNmYwr4
Follow the dots.
Now stare at the cross.
More
A Problem with Perspective…
There’s A Man In Here, But Where?
Facts Can Be Manipulated to Reach
Different Conclusions.
Count How Many People Are in the Picture
Clouds Are Beautiful
Observe the Facts
• Read:
• Christie comes into class and sits in her regular
seat in the front row. The teacher walks in,
writes his name on the chalkboard, picks up the
attendance book, and calls out the students'
names to see who is present. Then he points to
Christie and says, "If anyone has any assigned
homework from last night, please give it to this
girl now.“
• Name all you observe from the following
scenario?
• What is the situation?
Answer
• From the facts, you can infer that the
teacher is a substitute teacher.
– Why? He wrote his name, probably because
the students didn't know who he was. If he
were the regular teacher, he'd probably have
known Christie's name and not called her "this
girl." And he's unsure if students had
homework from the day before, probably
assigned by their regular teacher.
• Without all the facts it’s hard to make
decisions…so we need to ask questions.
Sample
Homer notices that his shower is covered in a strange green slime. His friend
Barney tells him that coconut juice will get rid of the green slime. Homer decides
to check this out by spraying half of the shower with coconut juice. He sprays the
other half of the shower with water. After 3 days of "treatment" there is no
change in the appearance of the green slime on either side of the shower.
1. What was the initial observation?
2. What is Barney’s hypothesis?
Identify the3. Control Group
The shower side sprayed with water
4. Independent Variable
The shower side sprayed with coconut juice
5. Dependent Variable
None…But what would it be if this was a successful experiment?
6. What should Homer's conclusion be?
That the coconut juice does not work on the slime. Barney’s crazy.
You have a problem…
"Early to bed, early to rise makes a man healthy, wealthy and
wise," said Ben Franklin. But does this adage apply to teenagers?
Research in the 1990s found that later sleep and wake patterns
among adolescents are biologically determined; the natural
tendency for teenagers is to stay up late at night and wake up
later in the morning. This research indicates that school bells that
ring as early as 7:00 a.m. in many parts of the country stand in
stark contrast [the start times contradict] with adolescents' sleep
patterns and needs.
Evidence suggests that teenagers are indeed seriously sleep
deprived. A recent poll conducted by the National Sleep
Foundation found that 60% of children under the age of 18
complained of being tired during the day, according to their
parents, and 15% said they fell asleep at school during the year.”
http://www.sleepfoundation.org/article/sleep-topics/school-start-time-and-sleep
How Would You Prove It?
• High school starts early in the morning but there are
highly educated researchers that claim that if high
school was started just 1.5 hours later students’
scores and health would increase.
• In your groups develop a good strategy that you could
use to help prove that sleep does in fact help students
in their studies.
• You will have 5 minutes then we will discuss.
Practice with Scientific Method
• Objectives:
• Identify aspects (hypotheses, controls,
variables, conclusions) of the scientific method.
– Whole class = Simpson’s examples
• Identify aspects of the scientific method in
groups.
– SpongeBob Worksheet
– 25pts.
• Mythbusters
– Watch & critique an experiment conducted by the
team identifying how well they followed the
scientific method.
The Scientific Method
• Every day you most likely experience something that makes
you wonder…
– Why?
– How?
• Sometimes you may not believe something someone tells or
sells you.
– A positive behavior called skepticism.
• If you can’t look up the answer how would you find a
solution?
• What technique could you use to try and get the answer?
• The most highly effective technique you could use is the one
that has been used by scientists for thousands of years….