ENIVIRONMENTAL SCIENCE 8 / 26 / 16 Experimental Design (ppt) – NB #2 LT: Be able to identify the key concepts to experimental design.

-Synthesis of material on the right Notes Ppt Textbook Vocabulary NOTEBOOK #2: Experimental Design #2: Experimental Design Title on both sides (left side) (right side) -Graphs -Illustrations -Diagrams -Synthesis of material on the right Creativity/Color/Original work Notes Ppt Textbook Vocabulary Assignments Labs

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Science – is what you know and the things that you do! Interpret & Evaluate Observations Experiment Hypothesis Prediction

designing an experiment

A variable is something that changes.

6 concepts of experimental design independent variable dependent variable constants control group experimental group repeated trials

the variable that is changed on purpose by the experimenter independent variable the variable that is changed on purpose by the experimenter aka cause, stimulus, reason, manipulated variable, etc. This is the ‘’if” part of a hypothesis.

the variable that responds dependent variable the variable that responds aka effect(s), result(s), responding variable, etc. This is the ‘’then” part of a hypothesis.

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

control group the group (standard) to which everything is compared (often the “normal” condition)

the group(s) being tested with the independent variable experimental group 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.

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

IVCDV chart The is used to design an experiment. Ex: use of different amounts of fertilizer on plant growth

iv constants dv The variable (factor) that you will change is the independent variable. fertilizer This is what you are changing in order to test in the experiment such as the varied fertilizer amounts. 0 drops 2 drops 4 drops Plants with no fertilizer are the control. 6 drops

The dv would be data/ results that you collect in the experiment. iv constants dv fertilizer plant growth 0 drops The variable (factor) resulting from the independent variable is the dependent variable. 2 drops 4 drops 6 drops The dv would be data/ results that you collect in the experiment.

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

4 drops fertilizer 2 drops fertilizer 6 drops fertilizer no fertilizer

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

What are these called? CONSTANTS

dependent variable 29” What is this called? The plant growth that you observe here can be called . . .  the results (of adding fertilizer)  the response (to adding fertilizer) 13”  the effects (of adding fertilizer) 9” 7” dependent variable 2 4 6 22

Fertilizer becomes a constant. Type of soil becomes the IV. What do you do if you want to test the type of soil instead of fertilizer? iv dv constants plant growth fertilizer amt. of water type of plant type of planter size of planter amt. of soil type of light location type of soil type of soil fertilizer Fertilizer becomes a constant. Type of soil becomes the IV.

forming a hypothesis

V Chart

If fertilizer is added to plants, then plant growth will improve. iv constants amt. of water type of soil type of plant type of planter size of planter amt. of soil type of light location dv fertilizer plant growth + verb + verb If fertilizer is added to plants, then plant growth will improve.

If independent variable + verb, then dependent variable + verb. V Chart Independent Variable Dependent Variable + verb + verb If independent variable + verb, then dependent variable + verb. hypothesis

Know how to graph data Title the graph Set up the independent variable along the X axis Set up the dependent variable along the Y axis Label each axis and give the appropriate units Make proportional increments along each axis so the graph is spread out over the entire graph area Plot points and sketch a curve if needed. Use a straight edge to connect points unless told to extrapolate a line. Label EACH curve if more than one is plotted.