Do Now

Do Now

You have 5 minutes to answer the following question(s). When you are done take out your binder and turn to the notes section.

• What factors affect your ability to make an “A” in a class?

• What factors affect how fast a plant grows?

Announcements/ Expectations

• You will start seeing grades go in this weekend.

• Headings• Prepared for class– Binder, divider and composition notebook

• Class Points

Variables and Hypothesis

What is a variable?

• Scientists use an experiment to search for cause and effect relationships in nature.

• A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled.

Independent Variable

• Also called the manipulated variable.• This is the variable that the scientist will manipulate

to see how it affects the dependent variable. • The independent variable is the one that is changed

by the scientist. • To insure a fair test, a good experiment has only

one independent variable. • As the scientist changes the independent variable,

he or she observes what happens.

Dependent Variable• Also called the responding variable.• Are the result of something that the scientist

has changed • Is actually being measured in the experiment• The scientist focuses his or her observations

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

Controlled Variable

• Also called the constant variable• The control variable will be the one that does

not change.• Most experiments have more than one

controlled variable. • The control variable is something that is

constant and unchanged in an experiment.

Form a HypothesisHypothesis: an educated guess or prediction; an “if, then” statement

If independent/manipulated variable, then dependent/responding variable.

Break

Example• Mandy set up an experiment to show the

relationship between plant growth and amount of water given to the plants.

• The stated problem was "Does the amount of water affect the growth of bean seeds?”

• Mandy's hypothesis was written in "if-then" format:

• If I don't water my plants, then they will not grow.– Independent variable- Amount of water– Dependent variable- Plant growth

Use this hypothesis to identify the variables

If I leave all the lights on all day, then my electric bill will be high.

IV: ______________________

DV: ______________________

If I drink Mountain Dew before bed, then I will not sleep very much.

IV: ______________________

DV: ______________________

If I brush my cat more, then there will be less fur on my furniture

IV: ______________________

DV: ______________________

Now read the following experiment and identify the independent and dependent variables and write a

hypothesisElizabeth wanted to test if temperature affected how fast milk

goes bad and curdles. She left milk in a room temperature closet, a fridge, and a oven that was turned on low heat. She then measured how rotten the milk was after 10 days.

Hypothesis: ______________________________

IV: ____________________________________

DV: ____________________________________

Independent Practice

Worksheet ExampleHypothesis:______________________________

IV: ____________________________________

DV: ____________________________________

Independent Practice

Exit Ticket

What is an independent variable?

What is a dependent variable?

What is a hypothesis?

ACT Prep