Here’s what we’ve done so far… Unit 1: Reviewed basic stages of the scientific method Toured potential research areas on campus Notes on beginning a research project Submission of preliminary research ideas Learned what to look for in collecting info from primary research documents And now…

Research Design Unit 2

How to Structure an Experiment AkA Research Design Good design determines: whether an experiment is likely to succeed reliability of an experiment’s results

Main Components of Research Design Research design includes: hypothesis variables experimental and control groups constants

Hypothesis Testable proposed explanation for an observed event Defines what you want to test and the limits of your experiment Purpose: connects the changes made by the independent variable with the measurable effects on the dependent variable

A well-written hypothesis, Identifies a specific variable to be tested Determines how changes within the experiment will be measured and recorded Predicts the results of the experiment

For example: Question : What effect does temperature have on planaria reproduction? Cannot be answered in a single experiment Not clear how effect on reproduction is measured

Example (cont’d) Hypothesis: If temperature affects the rate of planaria reproduction, then planaria will reproduce more slowly in lower temperatures than in higher temperatures. Identifies one specific independent variable Clearly indicates how changes will be measured Makes a prediction which will be supported or rejected by the experiment

Variables Independent variable (IV): changed variable researched before experiment begins only 1 is present in an experiment done over time Dependent variable (DV): responding variable chosen based on background research Changed

Research Question: “How effective are plant-based insect repellents?” Independent Variable: Different types of plant -based repellents Dependent Variable: Total number of insect bites Size of insect bites