III. Conducting your experiment

THIS IS THE FUN PART!!!! You will conduct an experiment that will test to see if your hypothesis is correct. The experiment will have many experimental groups. An experimental group is a group of experiments that are absolutely identical in every way. One of your experimental groups may be your control (or control group). This is a group that is as close to “normal” as possible and is used to compare to the other control groups to see if there was a change. Below is an example of an experiment involving wave erosion on different sediment types.

A word about Variables…

A variable (in the scientific sense) is a change that occurs, or can occur, in your experiment. There are many types of variables. Below is a list of three types of variables you will encounter and how they relate to the above example of an experiment.

Independent Variable: The ONE thing that you change from one experimental group to another. Example: The type of sediment

Dependant Variable: The changes that you observe or measure in your experiment. Example: The Amount of erosion that takes place.

Controlled Variables:

The things you want to keep the same from one experimental group to another. Example: the same amount of sediment, the same size stream table, the same amount of water in the stream table, make the waves all the same, etc.

What do I need to put on my backboard?

The two main things you need to worry about for your backboard is your materials and your procedures. The formats for these are found on the next page. Page 26 of this booklet has a worksheet that you will need to fill out and describe all the parts of your experiment.