Integrating Experimental Design

into Science

The purpose of this PowerPoint is to present strategies to aid students at the high school and introductory college levels to:

Design experimentsWrite proceduresConstruct tables and graphsGenerate ideasWrite simple lab reports

Experimental Design DiagramTitle: The effect of ...IV... on ...DV...

Hypothesis: If the ...IV... is modified in this way,then this will happen to the ...DV...

Independent variable:

these boxesshow how theIV is modified

_____trials _____trials _____trials _____trials _____trials

Dependent Variable:

Constants:

Control:

Experimental Design Diagram

Title: The effect of different aged compost on beanplant growth.

Hypothesis: If older compost is applied, then plantgrowth will be increased.

Independent variable: Age of Compost

these boxesshow how theIV is modified

3 month oldcompost

6 month oldcompost No compost

# trials 25 trials 25 trials 25 trials

Dependent Variable: Height of plants (cm)

Constants: amount of light, water, compost

Control: no compost

Generating Experimental Ideas

4 Question Strategy

Q1 – What materials are readily available for conducting experiments on ____________

Q2 – How do ______ act?Q3 – How can I change the set of ____

materials to affect the actionQ4- How can I measure or describe the

response of ____ to the change?

EXAMPLEQuestion 1

What materials are readily available for conducting experiments on plants?

SoilFertilizerWaterLight/heatContainers

EXAMPLEQuestion 2

How do plants act?

GrowWiltFlower

EXAMPLEQuestion 3

How can I change the set of plant materials to affect the action?

Water – amount, method of application, source, pH

Containers – location of holes, number of holes, shape, material, size

Plants – spacing, kind, age, size

EXAMPLEQuestion 4

How can I measure or describe the response of plants to the change?

Count the number of leavesMeasure the length of the longest

stemCount the number of flowersDetermine the rate of growthMass the fruit produced

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Practice

Constructing Tables and Graphs

Constructing Data Tables

Things to consider when constructing a table Does the system communicate the

relationship between the IV and DV? Does the system communicate the order

in which the IV was changed? Does the system’s title communicate the

purpose of the experiment? Are the units of measurements

communicated?

Bar vs. Line

DISCRETE DATA – CATEGORICAL OR COUNTED (DAYS OF THE WEEK, GENDER, COLOR)

CONTINUOUS DATA MEASUREMENTS INVOLVING A STANDARD SCALE WITH EQUAL INTERVALS; CONTINUOUS RANGE OF MEASUREMENTS

Bar vs. Line

The effect of coloration on the number of kittens

sold at a pet store

Bar

The effect of concentration of sugar water on the

number of visits of hummingbirds to a feeder

Line

The effect of the horsepower of a tractor on the mass of a sled it can

pull

Line