Topic: Variables and Controls (ISN 23)

• EQ: What is scientific inquiry?

1. One way scientists find out about the world around us.

The scientific method is

2. A way scientists answer a specific question.

Problem/Question

Observation/Research

Formulate a Hypothesis

Experiment

Collect and Analyze Results

Conclusion

Communicate the Results

Steps of the Scientific Method

Step four of the Scientific Method • Experiment: Develop and follow

a procedure.

Include a detailed materials list.

The outcome must be measurable (quantifiable).

Experiment

•All Experiments include factors that have to be tested. These are called variables.

What is a Variable?

DEFINITION

Variable – Any factor that can change in a scientific investigation or experiment

2 types of variables

Types of Variables

1. Test/Independent VariableThe condition that is intentionally

changed by the investigator in an experiment

There can be only one in an experiment

Ask the question: What are we changing?

2. Outcome/Dependent Variable

The factors or conditions that will changeThe factors that you measure or observe as

dataThere can be one or moreAsk the question: What am I trying to

observe or measure?

Types of Variables

Controlled/Control GroupThe factors or conditions that are

kept the same (unchanged) in an experiment.

There are many controlled variables in an experiment

Types of Variables

Identify variables for the following experiments.

You can do it!

Practice

• Does changing the temperature of a ball affect the height the ball will bounce?

Testable Question #1

HotCold

Test/Independent Variable

Outcome/Dependent Variable

Identify Variables #1

Cold Hot

• Does changing the temperature of a ball affect the height the ball will bounce?

• Controlled Variables:

* Same ball

* Dropped from the same height

* Dropped onto the same surface

* etc…

Identify Variables #1

• Does changing the color of light affect the growth rate of plants?

Testable Question #2

Test/IndependentVari

able

Outcome/Dependent Variable

Identify Variables #2

• Does changing the color of light affect the growth rate of plants?

• Controlled Variables: * Same type / size of plant * Same wattage of bulb * Same amount of water * Same soil * Light on for the same amount of

time * etc…

Identify Variables #2

• How does the size of a parachute affect the time it takes a

hippo to fall 10 feet?

Testable Question #3

Test/Independent Variable

Outcome/Dependent Variable

Identify Variables #3

• How does the size of a parachute affect the time it takes a hippo to fall 10 feet?

• Controlled Variables:

* Same hippo

* Dropped from the same height

* Same parachute fabric

* Same length of strings on the parachute

* etc…

Identify Variables #3

What is the change variable in the experimental setup on the next page—what is the one thing the experimenter has changed with plant 1, 2 and 3?

In this case, the experiment is changing the amount of water that the plant receives each day.

Summarizing Activity(ISN 22)

• Complete the Simpsons Controls and Variables activity