Experimental Design

An experiment is used to find an answer to a question or to test a hypothesis.  In an experiment you perform tests on an object or a group of objects and then observe what happens.  Often you are able to see, hear, smell, feel or sometimes taste a change that has occurred.  The observations made about an experiment should be carefully recorded.  You must have accurate information to support or reject your hypothesis.  In an experiment you need the following things.

 Objective - What are you trying to find out?  This is sometimes called the research question.

Procedure - The STEP-BY-STEP directions for doing the experiment. (Another scientist should be able to duplicate you experiment by following your procedure.

Observation - A written record of what happened during and as a result of your experiment.

Independent Variable : The one part of the experiment that the scientist will change or tested.

Dependent Variable : What you are going to measure.  It depends on what you control or change.

Control : The group on which no variable is used.  It is the standard that they experimental group will be compared to.

Experimental Group : The group on which the variable is being tested.

Replicates : How many trials will you have.

Constants : The parts of the experiment that you have to keep the same between the two groups in order to make the experiment a fair test.