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JOAN CARTAN-HANSEN, HOST: WHEN

YOU USE THE SCIENTIFIC METHOD TO
ANSWER A QUESTION, YOU START

WITH AN EXPERIMENT.

AND YOU DESIGN YOUR EXPERIMENT
TO USE VARIABLES.

THERE ARE THREE KINDS OF
VARIABLES: INDEPENDENT,

DEPENDENT AND CONTROLLED.

LET'S SAY YOU WANT TO TEST IF A
BIG DOG EATS MORE THAN A SMALL

DOG.

THE INDEPENDENT VARIABLE IS THE
THING YOU CHANGE IN THE

EXPERIMENT.

IN THIS CASE, THE BIG DOG AND
THE SMALL DOG.

THE DEPENDENT VARIABLE IS ONE
YOU MEASURE.

IN OUR EXPERIMENT, IT'S THE
AMOUNT OF FOOD EACH DOG EATS.

THE CONTROLLED VARIABLES ARE THE
THINGS YOU WANT TO REMAIN THE

SAME OR CONSTANT.

IN THIS EXPERIMENT, YOU WOULD
WANT TO MAKE SURE THE DOGS EAT

AT THE SAME TIME,
EAT THE SAME FOOD, AND HAVE NOT

EATEN FOR THE SAME AMOUNT OF
TIME BEFORE THE EXPERIMENT.

ONCE YOU'VE IDENTIFIED YOUR
VARIABLES, YOU'RE READY FOR THE

EXPERIMENT.

AND YOUR DOGS ARE READY FOR
DINNER.

FOR MORE INFORMATION ABOUT
INVENTIONS AND THE SCIENTIFIC

METHOD, CHECK OUT THE SCIENCE
TREK WEBSITE.

YOU'LL FIND IT AT
IDAHOPTV.ORG/SCIENCE TREK

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