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Concepts of experimental design independent variable dependent variable constants control group experimental group(s) trials

A variable is something that changes.

independent variable the variable that is changed on purpose by the experimenter aka: chosen, cause, stimulus, tested, manipulated, etc.

dependent variable the variable that responds aka: observed, measured, effect(s), result(s), measurement(s), etc.

constants all factors which are NOT allowed to change during the experiment  stay the SAME

control group the group used for comparison (the normal or no treatment group)

experimental group(s) the group(s) being tested with the independent variable Each test group has only one factor different from the other test groups: the independent variable

Trials the number of times the experiment is repeated The more times you repeat the experiment, the more VALID your results are.

is used to design an experiment. IVCDV The chart

ivdv constants fertilizer The variable (factor) that you will change is the independent variable. These are the fertilizer amounts chosen and changed by the experimenter. 0 drops 2 drops 4 drops 6 drops Plants with no fertilizer make up the control or control group. 0 drops

ivdv constants plant height fertilizer 0 drops 2 drops 4 drops 6 drops The variable (factor) resulting from the independent variable is the dependent variable.

iv dv constants plant height fertilizer amt. of water type of soil type of plant type of planter size of planter amt. of soil type of light location 0 drops 2 drops 4 drops 6 drops These are the factors that must NOT change during experimentation. They must remain constant.

no fertilizer 2 drops fertilizer 4 drops fertilizer 6 drops fertilizer

no fertilizer 2 drops fertilizer 4 drops fertilizer 6 drops fertilizer What is this called? CONTROL What are these called? EXPERIMENTAL GROUP

What are these called? CONSTANTS

What is this called? The plant growth that you observe here can be called... the results (of adding fertilizer) the response (to adding fertilizer) the effects (of adding fertilizer) dependent variable

Form a Include the IV and DV Must be testable!

list and describe Specify size, amount, type, etc.

write down step-by-step instructions Be detailed- anyone should be able to repeat your experiment EXACTLY! Include safety precautions!

analyze Organize/create tables, charts, graphs, diagrams, etc. Calculate values- averages, totals, % change, etc.

draw 1. Restate the Question 3. EXPLAIN results- why and how? Was anything unexpected? 2. Is Your Hypothesis SUPPORTED or REJECTED? 4. Sources of Error? Changes and improvements? 5. What NEXT?