Steps+of+the+Scientific+Method+Reference+Guide

__**STEPS OF THE SCIENTIFIC METHOD REFERENCE GUIDE**__

The scientific method starts when you ask a question about something that you observe: How, What, When, Who, Which, Why, or Where? And, in order for the scientific method to answer the question it must be about something that you can measure, preferably with a number.
 * Question:**

Rather than starting from scratch in putting together a plan for answering your question, you want to be a savvy scientist using library and Internet research to help you find the best way to do things and insure that you don't repeat mistakes from the past.
 * Research**:

A hypothesis is an educated guess about how things work: "If _[I do this] _, then _[this]_ will happen."
 * Hypothesis**:

You need to be able to measure both "what you do" and "what will happen" in order for your hypothesis to be testable, and of course, your hypothesis should be constructed in a way to help you answer your original question.

CAUTION: You don't simply "guess." You're not taking a shot in the dark. You're not pulling your statement out of thin air. Instead, you make an "educated guess" based on what you already know and what you have already learned from your research.

Write the experimental procedure like a step-by-step recipe for your science experiment. A good procedure is so detailed and complete that it lets someone else duplicate your experiment exactly!
 * Test Your Hypothesis by Doing an Experiment:**


 * Key Elements:**
 * A detailed list of the materials you will need.
 * Description and size of all experimental and control groups, as applicable.
 * A step-by-step list of everything you must do to perform your experiment. Think about all the steps that you will need to go through to complete your experiment, and record exactly what will need to be done in each step.
 * The experimental procedure must tell how you will change your one and only independent variable and how you will measure that change.
 * The experimental procedure must explain how you will measure the resulting change in the dependent variable or variables.
 * If applicable, the experimental procedure should explain how the controlled variables will be maintained at a constant value.
 * The experimental procedure should specify how many times you intend to repeat your experiment, so that you can verify that your results are reproducible.
 * Think ahead about safety! Are there any safety precautions you should take? Will you need to wear gloves or protective eye gear? Do you have long hair that needs to be pulled back out of your face? Will you need to be near a fire extinguisher?

Scientists use an experiment to search for cause and effect relationships in nature. In other words, they design an experiment so that changes to one item cause something else to vary in a predictable way.
 * Variables:**

These changing quantities are called variables. A variable is any factor, trait, or condition that can exist in differing amounts or types. An experiment usually has three kinds of variables: independent, dependent, and controlled.

The **independent variable** is the one that is changed by the scientist and known ahead of time. It is the variable actually being tested. To ensure a fair test, a good experiment has only one independent variable. As the scientist changes the independent variable, he or she observes what happens.

The **dependent variable** is the variable that you are observing or measuring. Changes in the dependent variable are caused by and depend on the value of the independent variable.


 * Controlled Variables** - or **constants** - are all other factors that could affect the dependent variable. These variables should be kept the same for all of your test groups and monitored carefully.

Repeating a science experiment is an important step to verify that your results are consistent and not just an accident. Each time that you perform your experiment is called a **run** or a **trial**. So, your experimental procedure should also specify how many trials you intend to run. Most teachers want you to repeat your experiment a minimum of three times. Repeating your experiment more than three times is even better.
 * Reliability**:

Every good experiment also compares different groups of trials with each other. Such a comparison helps insure that the changes you see when you change the independent variable are in fact caused by the independent variable. There are two types of trial groups: experimental groups and control groups.
 * Experimental & Control Groups:**

The **experimental group** consists of the trials where you change the independent variable. For example, if your question asks whether fertilizer makes a plant grow bigger, then the experimental group consists of all trials in which the plants receive fertilizer.

In many experiments it is important to perform a trial with the independent variable at a special setting for comparison with the other trials. This trial is referred to as a **control group**. The control group consists of all those trials where you either leave out the independent variable or leave it in its natural state. In the above example, it would be important to run some trials in which the plants get no fertilizer at all.

Prepare a data table in your laboratory notebook to help you collect your data. A data table will ensure that you are consistent in recording your data and will make it easier to analyze your results once you have finished your experiment. In addition to your data, record your observations as you perform the experiment. Write down any problems that occur, anything you do that is different than planned, ideas that come to mind, or interesting occurrences. Be on the lookout for the unexpected. Your observations will be useful when you analyze your data and draw conclusions.
 * Data & Observations:**

Take some time to carefully review all of the data you have collected from your experiment. Think about the best way to summarize your data. Do you want to calculate the average for each group of trials, or summarize the results in some other way such as ratios, percentages, or error and significance?
 * Analyze Your Data**

Use charts and graphs to help you analyze the data and patterns. Did you get the results you had expected? What did you find out from your experiment? Really think about what you have discovered and use your data to help you explain why you think certain things happened.

Look at the results of your experiment with a critical eye. Ask yourself these questions:
 * Is it complete, or did you forget something?
 * Do you need to collect more data?
 * Did you make any mistakes?

Your conclusions summarize how your results support or contradict your original hypothesis. This is where you show what you have learned about your question. Follow these guidelines unless instructed otherwise:
 * Form a Conclusion:**


 * Summarize** your results in a few sentences and use this summary to support your conclusion.
 * Restate the question or purpose in the past tense.
 * State whether your results support or contradict your hypothesis.
 * Explain any unexpected results.
 * Evaluate your experimental procedure. Were mistakes made? Was it an affective test? Are your results reliable?
 * Suggest changes in the experimental procedure (or design) and/or possibilities for further study.