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Variables and Hypothesis. Variable. What is it? Variable : something that can change in an experiment. Most commonly known as the factor/thing being tested in the experiment. Example. The time it takes to run a kilometer depends on the amount of exercise a person gets.
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Variable What is it? Variable: something that can change in an experiment. Most commonly known as the factor/thing being tested in the experiment.
Example The time it takes to run a kilometer depends on the amount of exercise a person gets. What are the variables? amount of exercise time to run a km ***Must include how each variable is measured or described!!!
Example The higher the temperature of water, the faster an egg will cook. What are the variables? temperature of water time it takes an egg to cook
Types of Variables Independent/Manipulated Variable (IV): variable that is deliberately changed in order to test it (in most lab situations, you are changing this variable on purpose) Dependent/Responding Variable (DV): changes as a result of the independent variable: usually a measured change or visually observed change
Example The more you water the grass, the taller it will grow. IV amount of water DV height of the grass
Example More bushels of potatoes will be produced if the soil is fertilized more. IV amount of fertilizer DV bushels of potatoes produced
Types of Variables Control Variable (CV): A variable that is NOT changed. It is kept the same throughout and is often the most NORMAL situation. You compare the DV results to the CV results.
Students of different ages are given the same puzzle to assemble. The puzzle assembly time is measured. IV age of student DV time it takes to assemble the puzzle CV puzzle (same)
Tables: When creating data tables and graphs, the placement of the IV and DV is important. Title: Time to assemble a puzzle based on age Students of different ages are given the same puzzle to assemble. The puzzle assembly time is measured.
Graph X axis IV Y axis DV Students of different ages are given the same puzzle to assemble. The puzzle assembly time is measured. Time in Minutes Age of Students
Hypothesis • Hypothesis • possible explanation for a set of observations or an answer to a scientific question. • Based on a person’s observations and previous knowledge or experience. • Hypotheses must be testable through an investigation.
How to Write a Hypothesis • If the independent variablechanges then the dependent variablechanges . • Always write your hypothesis in the third person (no I or you statements).
Practice! • Write a hypothesis based on this question: • What is the relationship between free seating at lunch and the cleanliness of the tables?