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Creating a Hypothesis

What do you predict will happen when you do your experiment?!

It does not matter that your experiment has been done a thousand times before!

What matters is that you don't know the results and that you can independently find a verifiable answer.

Real hypotheses should be written before the experiment!

What does verifiable mean?

It does not matter that your experiment has been done a thousand times before!

What matters is that you don't know the results and that you can independently find a verifiable answer.

Real hypotheses should be written before the experiment!

Verifiable: capable of being tested (verified or falsified) by experiment or observation.

A hypothesis is a statement that proposes a possible explanation to some phenomenon or event.

A useful hypothesis is a testable statement which may include a prediction.

If … then …

Real hypotheses should be written before the experiment!

The key word is testable!

Testing a HypothesisYou will perform

a test of how two variables might be related.

This is when you are doing a real experiment.

You are testing variables.

Previous Observations

Usually, a hypothesis is based on some previous observation

For example: In November many trees undergo

color changes in their leaves AND the average daily temperatures are dropping.

Are these two events connected? How?

How are hypotheses written? Chocolate may cause pimples.

Salt in soil may affect plant growth. Plant growth may be affected by the color of

the light. Bacterial growth may be affected by

temperature. Ultra violet light may cause skin cancer. Temperature may cause leaves to change

color.

Do you think that these statements make good

hypotheses?

The word MAY does not suggest how we would prove these statements.

Chocolate may cause pimples. Salt in soil may affect plant growth. Plant growth may be affected by the color of

the light. Bacterial growth may be affected by

temperature. Ultra violet light may cause skin cancer. Temperature may cause leaves to change

color.

We need to create If… then… statements.

If… then… statementsOriginal: Ultra violet light may cause skin cancer. If… then… If skin cancer is related to ultraviolet light , then

people with a high exposure to UV light will have a higher frequency of skin cancer because…

Original: Temperature may cause leaves to change color. If… then… If leaf color change is related to temperature , then

exposing plants to low temperatures will result in changes in leaf color because…

VariablesIf… then… If skin cancer is related to ultraviolet light , then

people with a high exposure to UV light will have a higher frequency of skin cancer because…

If… then… If leaf color change is related to temperature , then

exposing plants to low temperatures will result in changes in leaf color because…

DEPENDENTVARIABLE

INDEPENDENTVARIABLE

VariablesIf… then… If skin cancer is related to ultraviolet light , then

people with a high exposure to UV light will have a higher frequency of skin cancer.

If… then… If leaf color change is related to temperature , then

exposing plants to low temperatures will result in changes in leaf color.

DEPENDENTVARIABLE

The variable that you observe and measure the

results

INDEPENDENTVARIABLE

The variable that you control and change.

Practice Chocolate may cause pimples. Salt in soil may affect plant growth. Plant growth may be affected by the color of

the light. Bacterial growth may be affected by

temperature.

Rewrite the first four hypotheses as If… then…

statements.Single underline the dependent variable

and double underline the independent

variable.

Your hypothesisWrite the hypothesis for your experiment as an If… then… statement using the worksheet.

Be sure to identify the dependent variable

and the independent variable.