Parts of a Controlled Experiment

I gave plot A one gallon of water perweek. I gave plot B twogallons of water perweek.After 4 weeks, thegrass in plot B wastaller than in plot ACan I say for sure that water affects

the height of grass?

A

B

1. Testable Question Def: This is a question that can be answered

by an experiment Usually only one factor at a time is

investigated Good examples:

***Does the amount of fertilizer affect the number of flowers on a plant?

Is a person’s heart rate affected by 5 hour energy?

Bad example: Why is the sky blue? What happens after you die?

2. HypothesisA hypothesis is NOT an educated

guess!Def: A hypothesis is an explanation

or prediction that can be tested

Good examples: Does the amount of fertilizer affect the

number of flowers on a plant? ***I think adding fertilizer will cause a plant to produce more flowers

Is a person’s heart rate affected by 5 hour energy? I think 5 hour energy does not affect a person’s heart rate

Bad example: Why is the sky blue? I think blue is pretty What happens after you die? I think I’ll be

reincarnated as a unicorn

3. Independent Variable

Def: One factor that is changed on purpose to see if it has an effect on whatever you’re testing

Does the amount of fertilizer affect the number of flowers on a plant?

***The independent variable would be the amount of fertilizer

4. Dependent VariableDef: What you measure or

observe as a resultDoes the amount of fertilizer

affect the number of flowers on a plant?

***The dependent variable would be the number of flowers that grow on the plant

5. ControlsDef: The things that are the

same for all experimental groups

Ex: ***water, sunlight, temp.

6. MaterialsDef: A list of what is needed

7. ProcedureDef: Step by step instructionsWhy is it important to write a good materials list

and procedure? Your experiment needs to be able to be

repeated so that someone else can see if they get the same results that you did

8. DataDef: Information collected from the experiment

(with units) organized in a table and/or graph

Title

Independent Variable

Depend. Variable

Start

at 0

9. AnalysisDef: An explanation of the dataWhat does the data tell you?Example: Because all of the plants

produced the same number of flowers, that must mean that fertilizer does not affect the number of flowers on a plant.

10. ConclusionDef: A summary of the

experiment. Includes what was learned and real world connections.

I gave plot A one gallon of water perweek. I gave plot B two gallons of water perweek.After 4 weeks, thegrass in plot B wastaller than in plot ACan I say for sure that water affects

the height of grass?

A

B

No! More than one factor is being changed. In this example it is water and sunlight.

A

B