How do you put together a Scientific Experiment

Hypothesis A tentative explanation for an

observation, phenomenon, or scientific problem that can be tested by further investigation. Usually written as an “if, then statement”

Independent Variable An independent variable is typically the

variable representing the value being manipulated or changed

Dependent Variable A dependent variable is the observed result

of the independent variable being manipulated

Control To verify or regulate (a scientific experiment)

by conducting a parallel experiment or by comparing with another standard.

Here is an example hypothesis:

If students ingest different amounts of sugar per day, then students ingesting the most sugar per day will receive the most referrals.

What would be the independent variable and dependent variable?

How could a control be established for the experiment?

Once an experiment is designed, the next step is to collect data.

Data should be collected in a structured and organized way. Independent variables should be

established The resulting dependent variables should

be collected

All collected “raw” data needs to be documented and presented in the form of a Data Table

Characteristics of a Data Table: Organized Table has a title appropriate to the data it

contains All table headings are labeled and

appropriate units are given

Construct a sample data table for our sugar/referral hypothesis presented a few slides back.

Data collected from an experiment must be analyzed in some way.

Depending on the type of test conducted and data collected the analysis could take on any format Comparing averages, graphing, various

calculations

One of the most important parts of an experiment

Which of the following conclusions do you find more convincing:

1) Increasing sugar consumption results in more referrals.

2) Students who ingest 500 grams of sugar per day receive on average 5 more referrals per week than do students who only ingest 200 grams of sugar per day.

The key to an effective conclusion is citing the actual results of the experiment within the statement.

Whenever you are asked to write a conclusion in this class it needs to contain a direct reference to the data and analysis of the experiment

An effective conclusion makes a defining statement about the experiment and what was learned from it. The conclusion then uses data and analysis generated in the experiment to support or justify the defining statement.

Without support or justification a defining statement looks more like an opinion than a researched conclusion.

Tablespoons of PB Consumed per day

Measured Monthly Hair growth (inches)

1 1.0

2 1.2

3 1.3

4 1.5

5 1.9

6 2.4

7 3.1

8 3.1

Develop a conclusion from the presented data and analysis following the structure we just discussed

Data Table for Monthly Hair Growth and PB Consumption