Testable QuestionsRules for Creating Them!

A good scientist asks many questions; however, only those questions that are testable using science experiments are useful to a scientist.

Read the following questions and decide if they are testable.

1. Do cats eat more in the daytime or nighttime?

2. On which continents can rainforests be found?

3. What would happen to a student if he/she didn’t sleep for 48 hours?

4. Which brand of dish soap makes the most bubbles: Dawn, Ivory, or Palmolive?

5. What is the best brand of breakfast cereal?

6. Does temperature affect the life of a battery?

7. Why is eating junk food bad for your health?

Testable questions are always about changing

one thing to see what the effect is on another

thing.

Now that you can identify a testable question…let’s see how to actually WRITE a testable question!

Sample Testable Question

Does changing the height of the ramp affect the speed of a car going down the ramp?

Testable Question Formats

Does changing _______ affect _______?

How does changing _____ affect _____?

If I change ______, will it affect ______?

In a scientific experiment, these two blanks have special names: variables – things that can change.

Testable Questions have two parts:

An independent variable

A dependent variable

Let’s compare the two types of variables… Independent Variable

CHANGEd by you on purpose

What you have CONTROL over

What you as a scientist MANIPULATE

There can be ONLY ONE

Dependent Variable What is

measured in the experiment

changes because of what you changed on purpose

Testable Question Formats

Does changing _______ affect _______?

How does changing _____ affect _____?

If I change ______ will it affect ______?

independentvariable

dependentvariable

independentvariable

independentvariable

dependentvariable

dependentvariable

Example: Does changing the height of the ramp affect the

speed of the car going down the ramp? Identify the IV and DV in this question.

Practice Does the temperature of water affect

the time it takes a sugar cube to dissolve?

Identify the INDEPENDENT variable

_________________________

Identify the DEPENDENT variable

_________________________

Hypothesis Writing

No it’s not JUST an educated guess!

What you need to know…A hypothesis is an “educated guess” about how

things work.

What does “educated” mean?You have to be “educated” on a topic before

you can “guess” about it! ….DUH!!!!

Most of the time a hypothesis is written like this: "If _____[I do this – independent variable], then _____[this – dependent variable] will happen." (Fill in the blanks with the appropriate information from your own experiment.)

Hypothesis

A hypothesis expresses your independent variable and your dependent variable.

"If I open the faucet [faucet opening size is the independent variable], then it will increase the flow of water [flow of water is the dependent variable].”

EXAMPLES"If I put fenders on a bicycle

[having fenders is the independent variable], then they will keep the rider dry when riding through puddles [the dependent variable is how much water splashes on the rider]."

EXAMPLESIf a plant receives fertilizer

[having fertilizer is the independent variable], then it will grow to be bigger than a plant that does not receive fertilizer [plant size is the dependent variable]."

EXAMPLES"Raising the temperature of a cup of water [temperature is the independent variable] will increase the amount of sugar that dissolves [the amount of sugar is the dependent variable]."

CHECKLIST

What makes a good hypothesis? For a good hypothesis, you have a checkmark in each box.

Is the hypothesis based on information contained in the Research Paper?

Does the hypothesis include the independent and dependent variables?

Have you worded the hypothesis so that it can be tested in the experiment?

• Start thinking about the hypothesis you wrote at the beginning of class. Use this checklist to see if you wrote a testable statement.

Now you try! What effect does high temperature have on radish germination?  Hypothesis- Independent variable: Dependent variable:

What effect does studying with music have on student test scores?  Hypothesis- Independent variable: Dependent variable:

Let’s practice writing a few…

Does carbon dioxide in the atmosphere cause the atmosphere to warm?

Ask yourself: 1. Which variable can I change ON PURPOSE

(IV)?2. What is going to change because of what

I changed (DV)?Write the testable question:Does changing the amount of carbon dioxide affect atmospheric temperatures?

Is achievement in school higher when students are tested frequently?

Ask yourself: 1. Which variable can I change ON

PURPOSE (IV)?

2. What is going to change because of what I changed (DV)?Write the testable question:How does frequency of testing affect student achievement?

Do crickets chirp faster in warmer temperatures or cooler temperatures?

Ask yourself: 1. Which variable can I change ON

PURPOSE (IV)?

2. What is going to change because of what I changed (DV)?Write the testable question:How does the change in temperature affect the speed of a cricket’s chirp?

Now you try! What effect does food color have on the amount of food fish eat?  Hypothesis- Independent variable: Dependent variable:

What effect does light have on plant growth?  Hypothesis- Independent variable: Dependent variable:

 

Now you practice on your own

Hypothesis Practice: all by your lonesome