DO NOW – LEVEL 0

Pass in Cornell Notes HomeworkRead “Risk Taking” Article

IDENTIFYING VARIABLES&DESIGNING INVESTIGATIONS

CAUSE AND EFFECT

Relationship between two things when one thing makes something else happen

Scientists use an experiment to search for cause and effect relationships

Experiments are made so that changes to one item cause something else to vary or change in a predictable way

EXAMPLE Does eating a McDonald’s Big Mac everyday

cause people to be obese? What is the cause and effect relationship?Which variable may

CAUSE something else to happen?

Which is changing due to the other one?

TESTABLE QUESTIONS

Turn cause and effect into something that can be tested They make a testable question

Testable Questions:1. Not based on opinion2. Must have clear cause and effect

relationship3. Must be measurable

DOES EATING A MCDONALD’S BIG MAC EVERYDAY CAUSE PEOPLE TO BE OBESE?

Let’s make it testable:

Does it have clear cause and effect? _________

Is it based on opinion? _________

Is it measurable? _______ How can we make it measureable?

______________________________________

NOT TESTABLE

YesNo

No

Explain what we will measure

TESTABLE QUESTION

What is the effect of eating a McDonald’s Big Mac every day on a person’s weight?

YOUR TURN

Write TQ next to each question that can be tested.

For the TQ’s circle the factor CAUSING something to change

And underline the EFFECT

For those that are not TQ’s, write why they are not testable

TQ OR NOT

1. Which type of music is better Hip Hop or Punk?

2. Does reading 30 minutes each night help your grades?

3. Will eating protein shakes increase my upper body strength?

4. Which brand of shoe is better for running, Nike or Adidas?

5. Does fertilizer help a plant grow taller?

EXPERIMENTAL VARIABLES

Independent Variable – something that is changed by the scientistWhat is being testedWhat is manipulated/changed

What is the effect of eating a McDonald’s Big Mac every day on a person’s weight?

Independent Variable???

IV = Amount of Big Macs that someone eats

EXPERIMENTAL VARIABLES

Dependent Variable – something that might be affected by the change in the independent variableWhat is observedWhat is measuredThe data collected during the investigation

What is the effect of eating a McDonald’s Big Mac every day on a person’s weight?

Dependent Variable???

DV = Person’s Weight in (kg)

EXPERIMENTAL VARIABLES

Controlled Variable – a variable that is not changed, kept the same or constant Also called constantsAllow for a “fair test”

FOR EXAMPLE:

STUDENTS OF DIFFERENT AGES WERE GIVEN THE SAME JIGSAW PUZZLE TO PUT TOGETHER. THEY WERE TIMED TO SEE HOW LONG IT TOOK TO FINISH THE PUZZLE.

IDENTIFY THE VARIABLES IN THIS INVESTIGATION.

WHAT WAS THE INDEPENDENT VARIABLE?

Ages of the studentsDifferent ages were tested by the scientist

WHAT WAS THE DEPENDENT VARIABLE?

The time it to put the puzzle togetherThe time was observed and measured by the scientist

WHAT WAS A CONTROLLED VARIABLE?

Same puzzleAll of the participants were tested with the same puzzle.

It would not have been a fair test if some had an easy 30 piece puzzle and some had a harder 500 piece puzzle.

ANOTHER EXAMPLE:

THE HIGHER THE TEMPERATURE OF WATER, THE FASTER AN EGG WILL BOIL.

Independent variable – temperature of water

Dependent variable – time to cook an egg

LAST ONE:

THE TEMPERATURE OF WATER WAS MEASURED AT DIFFERENT DEPTHS OF A POND.

Independent variable – depth of the water

Dependent variable – temperature

DESIGNING INVESTIGATIONS

THE GREATER THE AMOUNT OF SOAP IN A SOAP AND WATER MIXTURE, THE BIGGER A SOAP BUBBLE CAN BE BLOWN.

Design an investigation to test this hypothesis.

Identify the variablesWhat exactly will be changed?

How will it be changed?What exactly will be measured?

How will it be measured?

THE FARTHER A BALL DROPS, THE HIGHER IT WILL BOUNCE.

Design an investigation to test this hypothesis.Identify the variablesWhat exactly will be changed? How will it be changed?

What exactly will be measured? How will it be measured?

http://www.youtube.com/watch?v=tG5NX7fC8VM&p=F515918DB6082821&playnext=1&index=15

What color do Sharks prefer?

WHILE WATCHING VIDEO: What is the IV

Remember: this is the variable that is being changed

What is the DVThis is the variable that is being

measured What is the testable question?