Hypothesis & Variables Notes

THE SCIENTIFIC METHOD

Forming a scientific hypothesis and identifying

scientific variables

Learning Target:
identify and form
independent and
dependent variables in
order to help form a good
hypothesis

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What is a hypothesis?

•An hypothesis is a proposed answer to a scientific question (an
educated guess)

•Scientist must do 2 things BEFORE forming a “Good”
hypothesis:

•Perform Background Research

•Identify Independent & Dependent Variable from the scientific
question

•A hypothesis is written in the form of a STATEMENT
NOT A QUESTION!

What must a Hypothesis have to be
considered correct?

A Good Hypothesis must be...

• A proposed answer/prediction to a question

• Must show a cause-effect relationship with the independent
dependent variable

• Written in away that it can be tested
using If.....then….because...

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Drag and Drop

Your hypothesis should always include

Placeholder

explaining what you will test, ​

Placeholder

for what you predict will happen, and ​

Placeholder

explaining why you predict that.

Drag these tiles and drop them in the correct blank above

If...

then...

because...

My prediction

My claim

My reasoning

A Hypothesis refers to a cause and effect

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Example: If plants get less sunlightthen they will grow less
Because plants use sunlight to produce food and grow.

A Hypothesis refers to a cause and effect

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Example: If a person eats more fiber bars,then they will use the
bathroom more regularly because fiber regulates the digestive system

Comparing a good and a bad hypothesis

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If an athlete drinks Gatorade
then it will make them jump
highest because it helps the
muscles work better.

If an athlete drinks Gatorade
then it will make them run
faster because it helps
replenish electrolytes in the
body.

Does Gatorade have an effect on how fast athletes run?

BAD

GOOD

Time to Practice!

Write a hypothesis for the
following questions in your
digital science journal.

Don’t forget to use if…

then I predict… because...
1.Does copper or
aluminum conduct
electricity better?

2. Do Mentos react with
more with Coke or Diet
Coke?

3. Does black or white
materials absorb more solar
energy and heat?

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Open Ended

Write a hypothesis for the following experiment: Will black or white material absorb more heat?

Open Ended

Write a hypothesis for the following experiment: Does copper or aluminum conduct electricity better?

What are the THREE Variables?

✘Independent Variable (IV) or Manipulated: the one factor
that is changed by the person doing the experiment
✗

This is the CAUSEin an experiment and is explained in
the first part of your hypothesis

✘Dependent Variable (DV) or Responding: the factor which
is measured in the experiment

✗

This is the EFFECT in an experiment and is the results
you are predicting.

✘Constants or Controlled Variable: all the factors that stay
the same in an experiment

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Examples of variables

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●What would be your Independent Variable (IV) or manipulated and changed
part of your experiment?

●What would be your Dependent Variable (DV) or measured and responding
part of your experiment?

●What would be your Constants or Controls that would be the same for all
three bird feeders?

Types of variables

● Independent Variable: color of the feeders

● Dependent Variable: amount of seed

eaten

● Constants: everything else that is kept the

same, for example:

– the location of the feeders

– the kind of feeder used

– putting the feeders out at the same time

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Amount of Seed
Eaten

Blue

Amount of
Seed Eaten

Amount of Seed
Eaten

Dependent
Variable

Green

Red

Independent
Variable

Location of feeders
Kind of seed
Type of feeder

Constants

Time to Practice!

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Terry loves birds and wants to see as many as she can in her
yard. She wants to know whether she is wasting money
buying an expensive mixed seed, when a cheaper brand just
arrived at her local store. She wonders… will the expensive
seed attract more birds to her back yard?

How would you advise her to find out if the expensive seed is better?

What would be the variables in her experiment?

Categorize

Options (6)

What is CHANGED in the experiment

Expensive or cheap bird seed

What is MEASURED in the experiment

How many birds eat the food

What is kept the SAME in an experiment

Type of feeder, amount of time birds are watched

Terry loves birds and wants to see as many as she can in her
yard. She wants to know whether she is wasting money
buying an expensive mixed seed, when a cheaper brand just
arrived at her local store. She wonders… will the expensive
seed attract more birds to her back yard?

Independent or Manipulated

Dependent or Responding

Controlled

Terry’s Experimental Design

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Independent Variable
(IV) or Manipulated
What is Changed?

Dependent Variable
(DV) or Responding
What is measured?

Constant or Controlled
What stays the same?

Terry’s Experimental Design

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Independent Variable
(IV) or Manipulated
What is Changed?

Type of bird seed

●Expensive

●cheap

Dependent Variable
(DV) or Responding
What is measured?

Amount of seed the birds eat

Constant or Controlled
What stays the same?

Same bird feeder, same location, same amount of
days, same time of year