CATALYST 1.) Pick up your HOMEWORK PACKET and graded quizzes in the graded work folders.

2.) Answer the following questions on the LEFT PAGE:

What is an independent variable? What is a dependent variable?

Agenda

• Quick Reminders

• Quiz Tracker

• Variables•Independent •Dependent

• Practice

• Wrap Up

General Science – Tues, 09.02.2008

Quick Reminders

•Bring science fair notebook tomorrow!

•HW Packet #3 Due Friday, 09.05.2008.

• Quiz #3 on Friday, 09.05.2008.

General Science – Tues, 09.02.2008

QUIZ TRACKER

General Science – Tues, 09.02.2008

TRACKER

Quiz Grade 1 M A A E M A EQuiz Grade 2 MUnit Test GradeMidterm Grade

ObjectivesSWBAT:

Articulate what independent and dependent variables are.

Write a statement which contains independent and dependent variables.

Variables 09.02.2008

VariableDefinition“varius” (Latin)

means “changing” “able” (Latin)

is used to form words that describe (adjectives) and means “capable or worthy of”

So when you combine the two roots of the word variable you get the meaning:Something that is capable of changing

Variables 09.02.2008Origin -Varius (“changing”) + able

(“capable of”) = variable (“capable of changing”)

Variable

In a scientific experiment, a variable is anyfactor or trait or condition that can exist in

differing amounts or types.EX: The effect of weather conditions on the

amount of citrus fruit produced.

Why are variables important in scientific inquiry?

Scientists use variables in their

experiments to search forRelationships in nature.

Variables 09.02.2008Origin

Importance

-Varius (“changing”) + able (“capable of”) = variable (“capable of changing”)

- Helps find relationships in nature

Why are variables important in scientific inquiry?In other words, they design an experiment so

that changes to one item cause something else to vary (change) in a predictable way.

Variables 09.02.2008Origin

Importance

-Varius (“changing”) + able (“capable of”) = variable (“capable of changing”)

-Helps find relationships in nature- Setup expmts. to change one item & see how affects other items

Types of Variables

An experiment usually has three kinds of variables: independent, dependent, and controlled.

Today we are only going to talk about independent and dependent variables.

Independent Variable

An independent variable (IV) is a variable in the experiment that the experimenter changes or manipulates

Independent variable is

what I can change.

Variables 09.02.2008Origin

Importance

Types

-Varius (“changing”) + able (“capable of”) = variable (“capable of changing”)

-Helps find relationships in nature- Setup expmts. to change one item & see how affects other items

- Independent (IV) – experimenter changes (“Independent = I change”)

Independent Variable

As the scientist changesthe independent variable,he or she observes whathappens.

Dependent VariableThe dependent variable is

what changes when the independent variable

changes

The dependent variable is what

we measure

Variables 09.02.2008Origin

Importance

Types

-Varius (“changing”) + able (“capable of”) = variable (“capable of changing”)

-Helps find relationships in nature- Setup expmts. to change one item & see how affects other items

-Independent (IV) – experimenter changes (“Independent = I change”)

- Dependent (DV) – what changes when IV changes; what we measure

Dependent VariableThe scientist focuses his or her observations on

the dependent variable to see how it responds tothe change made to the independent variable.

The new value of the dependent variable is caused by and depends on the value of the independent variable.

Practice Identifying VariablesQUESTION 1

How much water flows through a faucet at different openings (closed, half open, fully open)?

INDEPENDENT VARIABLE

DEPENDENT VARIABLE

Variables 09.02.2008Types

Examples

-Independent (IV) – experimenter changes (“Independent = I change”)

-Dependent (DV) – what changes when IV changes; what we measure

- Q1: How much water flows through a faucet at different openings?

Practice Identifying VariablesQUESTION 1

How much water flows through a faucet at different openings (closed, half open, fully open)?

INDEPENDENT VARIABLEWater faucet opening (closed, half open, fully open)

DEPENDENT VARIABLE Amount of water flowing measured in liters per minute

Variables 09.02.2008Types

Examples

-Independent (IV) – experimenter changes (“Independent = I change”)

-Dependent (DV) – what changes when IV changes; what we measure

- Q1: How much water flows through a faucet at different openings? IV1: Water Faucet Opening (Closed / Half Open / Fully Open) DV1: Amount of Water Flowing

Practice Identifying VariablesQUESTION 2

Does heating a cup of water allow it to dissolve more sugar?

INDEPENDENT VARIABLE

DEPENDENT VARIABLE

Practice Identifying VariablesQUESTION 2

Does heating a cup of water allow it to dissolve more sugar?

INDEPENDENT VARIABLETemperature of the water measured in degrees Celsius

DEPENDENT VARIABLE Amount of sugar that dissolves completely measured in

grams

Practice Identifying VariablesQUESTION 3 (ON LEFT PAGE)

Does an electric motor turn faster if you increase the voltage?

INDEPENDENT VARIABLE

DEPENDENT VARIABLE

Practice Identifying VariablesQUESTION 3 (ON LEFT PAGE)

Does an electric motor turn faster if you increase the voltage?

INDEPENDENT VARIABLEVoltage of the electricity measured in volts

DEPENDENT VARIABLE Speed of rotation

Variables OVERVIEWIndependent Variables

What I change

Dependent Variables What is being measured

SUMMARY & PRACTICETake 3 minutes to write your summary.

When you are done, begin working on your HW Packet!