HYPOTHESIS AND VARIABLES

Step 3: Form a Hypothesis

Hypothesis- a testable explanation of an observation.

A hypothesis is NOT just an educated guess about what you think will happen. It must be able to be tested!

Step 3: Form a Hypothesis

We write the hypothesis in an If-Then statement

ex: If the amount of fertilizer is increased, then the height of the

plant will increase.

Variables & Controls

A variable is anything that changes in a scientific experiment.

The control is what you use to compare the results to in the end of the experiment.

There are 2 types of variables: Independent Dependent

Step 3: Form a Hypothesis

The Independent Variable goes after the “If”

I.V. If the amount of fertilizer is increased, then the height of the plant will increase.

Step 3: Form a Hypothesis

The Dependent Variable goes after the “Then”

If the amount of fertilizer is increased, then the height of the plant will increase.

D.V.

Now You Try:

If you spend more time studying, then your grade will improve.

Independent Variable = Dependent Variable =

Now You Try:

If you spend more time studying, then your grade will improve.

Independent Variable = amount of time spent studying

Dependent Variable = grade

Now You Try:

If the temperature of the room is increased, then the bacteria will grow faster.

Independent Variable = Dependent Variable =

Now You Try:

If the temperature of the room is increased, then the bacteria will grow faster.

Independent Variable = temperature of room

Dependent Variable = bacterial growth

Variables & Controls

A variable is anything that changes in a scientific experiment.

The control is what you use to compare the results to in the end of the experiment.

2 Types of variables:

Independent Variable: What you change.

Dependent Variable: What changes because of the Independent Variable.

2 Types of variables:

Independent Variable: Cause

Dependent Variable: Effect

Independent Variable

Independent Variable: What you change.

Cause a.k.a Manipulated Variable Graphed on x axis

Dependent Variable

Dependent Variable: What changes because of the Independent Variable.

Effect a.k.a Responding Variable Graphed on y axis

Independent Variable vs. Dependent Variable

Independent Variable

Dependent Variable

Also Known As:

Manipulated Variable

Responding Variable

Results: Cause Effect

On a graph: X axis Y axis

After all of the data from the experiment is collected, then its time to organize the data.

Step 6: Organize your data Put your data into a data table

IndependentVariable

__________(unit)

Levels

Dependent Variable _______________ (unit)

Trial 1 Trail 2 Trail 3 mean range

Step 6: Organize your data Make the data table into a graph

GRAPHS make it EASIER to see patterns in the data!

Step 6: Organize your data

How do you know what goes on each axis of the graph?

Step 6: Organize your data

DRY MIX Dependent Variable = Responding Variable = Y

axis Manipulated Variable = Independent Variable =

X axis

Parts of a graph

Y Axis

X Axis

Parts of a graph

Y Axis (Dependent Variable)

X Axis (Independent

Variable)

Graphing: DRY MIX

Independent Variable

Dep

ende

nt V

aria

ble

Any Questions????