ENVIRONMENTORS FORMING YOUR HYPOTHESIS &DESIGNING YOUR EXPERIMENTChapter Name

Date

ENVIRONMENTORS STEPS

Choose your project topic

Conduct your background research

FORM YOUR HYPOTHESIS

DESIGN YOUR EXPERIMENT

Conduct at least 3 experimental trials

Analyze data and draw a conclusion

Communicate your results

FORM YOUR HYPOTHESIS

WHAT IS A HYPOTHESIS- A tentative statement about an observation,

phenomenon, or scientific problem1

- This statement is your educated attempt to explain or predict the relationship between two or more variables2

- This prediction (what you expect to happen in your study) must be testable2

- Often takes the form of an “if…then…” statement. You predict that IF you change one variable, THEN some change will happen to another variable.

1. http://www.sciencekidsathome.com/science_fair/what-is-a-hypothesis.html

2. http://psychology.about.com/od/hindex/g/hypothesis.htm

WHAT IS NOT A HYPOTHESIS- A guess – your hypothesis is based on lots of

background research and thinking to help you make an educated prediction.

- Necessarily the right answer – you’re just proposing one possible explanation out of many

- Something that can never be tested – you have to be able to study what you predict, so it can’t be an isolated incident

KNOWING YOUR VARIABLES Independent - the one that you change or manipulate,

and predict will influence other things. This is the only thing you’ll change in your experiment.

Dependent – these are the things that you predict will change in a consistent manner in response to changes in the independent variable. These are the things you’ll be collecting data about during your experiment.

Controlled – these are things that can also influence the dependent variables and confuse your results. You’ll try to CONTROL for these variables throughout your experiment by keeping them constant. Most experiments will have more than one controlled variable.

FORMING YOUR HYPOTHESIS

Your hypothesis should take the following form:

IF the independent variable is changed in a certain way

THEN the dependent variable(s) will change in a predictable manner

DESIGN YOUR EXPERIMENT

EXPERIMENTAL PROCEDURE

Now that you have your hypothesis you need to design the best way to test it. Your procedure should be:

-Replicable (by yourself AND others). You should run your experiment or take data samples for each independent variable at least 3 times.

-Clear (specific, step-by-step instructions and materials) that someone could understand just by reading your notes. You should pinpoint your study location(s), materials, and sampling technique.

EXPERIMENTAL AND CONTROL GROUPS

You run your experiment and have data – great! But how do you know that the changes you saw in your dependent variables are due to the changes you make in the independent variable, and not just random or normal?

You don’t, unless you have something to compare your experimental trials to: a control group!

Control groups - the set of experimental trials where the independent variable is set at its natural state

Experimental groups - the set of experimental trials where THE ONLY THING you change the independent variable

MATERIALS LIST

A Good Materials List Is Very Specific X A Bad Materials List

500 ml of de-ionized water Water

Stopwatch with 0.1 sec accuracy Clock

AA alkaline battery Battery