1. What is an Experiment? An organized procedure for testing a hypothesis
Good experiments produce accurate (reproducible) results
Good experiments are easily re-done; followed by someone else

2. The Problem
You are working at a movie theater and the manager approaches you complaining about the amount of un-popped popcorn kernels. She complains that the theater is loosing money because of wasted, un-popped popcorn.
Design an experiment to solve the problem. HINT: Popcorn is thought to pop better if stored at cold temperatures!!

3. Parts of an Experiment
Any good scientific experiment needs a CONTROL; something used for comparison
Conclusions can not be made without a control
The control shows that the experimental results are related to the defined problem (what you are testing)
Ex: If you hypothesize that the popcorn will pop better after being stored in the freezer, you must also test how it pops after being stored at room temperature. This is your comparison or control.
Control: Popcorn stored at room temperature

4. Parts of an Experiment Scientific experiments also have CONSTANTS
CONSTANTS are factors that don’t change during an experiment
Constants allow you to test one variable at a time
Constants help ensure accurate results!!
You want to keep as many things constant as possible
Ex: Brand of popcorn, popping conditions,storage time, etc. must be constant!!

5. Parts of an Experiment
Good scientific experiments have ONE independent variable
Independent Variable – what you are testing: you purposely change this during the experiment
Ex: Effect of storage temperature on the popcorn**

6. Parts of an Experiment
Good scientific experiments have at least one Dependent Variable
Dependent Variable: changes because of the independent variable; depends on the independent variable
Ex: Number of un-popped popcorn kernels

7. Parts of a Scientific Experiment
Control: Used as a comparison; validates results
Ex: Popcorn stored at room temp.
Constants: things that are purposely kept the same during the experiment; validates the cause
Ex:Brand of popcorn, time stored, popping conditions, etc.
Independent Variable: the thing being tested and purposely changed during the experiment; should only be one thing!
Ex: Storage temperature
Dependent Variable: the thing that changes because of the independent variable (depends on the independent variable)
Ex: Amount of un-popped kernels

8. The Data Data – information gathered during an experiment
Data can be qualitative (descriptive) or quantitative
Descriptive data – comes from your senses; what you see, smell, feel, hear, or taste.
Quantitative data – recorded as numbers or values – comes from measurements, weight, temperature, calculations, etc.
Scientific experiments often use both types of data!