Variables Scientific Inquiry! This unit on Scientific Method & lab

Bell-Ringer Get out your Choice book. Silent reading for 10 minutes.

OBJECTIVE 1-3 SWBAT identify variables.

VARIABLES (Write down) Science is largely about manipulation and observation. Manipulation: to purposefully change Observation: to notice/measure and record

VARIABLES (Write down) So what is a variable? Variable: a factor/part of an experiment that changes (varies)

VARIABLES (Write down) There are 3 main types of variables: Independent variables: the variable that the scientist changes. This is the ONE thing that is being tested. Everything else must stay the same! Dependent variables: the variable that the scientist measures/observes. This variable is directly affected by the independent variable. Control variables: The variables that stay the same between all trials or groups. Hint: Write these down!

VARIABLES (Write down) Why do we need to keep things the same? Let’s compare 2 experiments. Both are trying to see if increasing fertilizer will affect the growth of a plant.

EXPERIMENT 1 (Don’t write) What did we change in this experiment? What can we conclude from this experiment?

EXPERIMENT 2 (Don’t write) What did we change in this experiment? (What type of variable is this?) What was our dependent variable? What was our control variable? What can we conclude from this experiment? What made Experiment 2 better than Experiment 1? How many independent variables are you allowed to have in a given experiment?

EXAMPLE (Don’t write) Two groups of students were tested to compare their speed working math problems. Each group was given the same problems. One group used calculators, the other group computed without calculators. IV: calculators DV: speed working math problems CV: math problems

PRACTICE (Don’t write) Students of different ages were given the same puzzle to assemble. The puzzle assembly time was measured. IV: age DV: puzzle assembly time CV: puzzle