Introduction: How to Conduct Experiments Using the Scientific Method
Experiments are performed all around us everyday. Whether they're done to find out if a cancer curing medication works or to find out how fast water evaporates at certain temperatures, experiments are constantly performed. However, what separates a simple experiment from a professionally done experiment is the use of the Scientific Method.
The Scientific Method is a series of organized steps to which an experiment is done. The Scientific Method helps you plan, predict, research, conclude and maybe even publish your findings. The Scientific Method will make your experiment more organized, easy to interpret and learn from.
In this Instructable, I will help guide you through each step using a sample experiment. You will also learn the significance of each step as I break the Scientific Method down.
The steps to the Scientific Method are:
1) Pose a Testable Question.
2) Conduct Background Research.
3) State your Hypothesis.
4) Design Experiment.
5) Perform your Experiment.
6) Collect Data.
7) Draw Conclusions.
8) Publish Findings (optional).
Step 1: Understand the Sample Experiment
Our sample experiment is going to be the rate of sugar cubes dissolving in water at different temperatures. Basically, I will drop sugar cubes into cups of water with different temperatures and time how long it takes the sugar cubes to "disappear" (dissolve).
Step 2: Pose a Testable Question
The Testable Question is the question that the experiment is based on. Every experiment is performed because someone questions or is curious about something. So, all the Testable Question really does, is pose that burning question.
In the sample experiment, our Testable Question is:
Does water temperature affect the rate at which sugar cubes dissolve?
Step 3: Research the Topic
Researching your topic is very important. It helps you predict an outcome (Hypothesis) and helps you to better understand the subject.
Your research should include, information about prior experiments done that are the same or similar to yours, information about things you are using in your experiment (chemicals, tools, etc.), definitions of words that you don't know that are relevant to your experiment, etc.
Your research doesn't need to be organized in any particular fashion. Some ways to organize your information are bullet points, charts and graphs (t-charts, spreadsheets, bar graphs, line graphs, etc.), list of words and their respective definitions, etc.
Step 4: State a Hypothesis
The Hypothesis is a prediction, based on prior research, on the outcome of the experiment. Think of the Hypothesisas an educated estimate.
Your Hypothesis will predict your opinion on the outcome of the experiment. If research points one way, and you predict that your experiment will go another way, that's totally fine. That's the point of doing the experiment. To see if your Hypothesis is right or wrong.
A Hypothesis is usually stated using a 'if and then' statement. Your sentence will sound something like, If I drink water, then I will feel hydrated.
In the sample experiment, theHypothesiscan be:
If you increase water temperature, then the rate at which a sugar cube dissolves is increased.
Remember, the hypothesis can be any prediction of the outcome of the experiment you are conducting. So, again, this doesn't have to be your hypothesis.
Step 5: Design Your Experiment
There are five main things to cover in the design step. Those five things are:
1) Make a list of parts, materials and tools needed for your experiment.
2) Declare your control.
3) Declare your independent variable.
4) Declare your dependent variable.
5) Describe how you will perform your experiment.
Make a List of Parts, Materials and Tools Needed for your Experiment
For the sample experiment I will need:
- Two clear plastic cups filled with half a cup of water
- A thermometer
- Two sugar cubes
- Distilled water
- A stopwatch
- A measuring cup
- Two microwaveable bowls
Declare your Control Variable
The control variable is the normal scenario.
For the sample experiment, the control variable is:
- A cup of water that is room temperature (seventy two degrees Fahrenheit).
Declare your Independent Variable
The independent variable is the one variable you change that makes the scenario different than normal conditions (control).
For the sample experiment, the independent variable is:
- Increasing the water temperature to about ninety five degrees Fahrenheit. This is the independent variable because the control, or normal scenario is about seventy two degrees Fahrenheit.
Please note that you can only change one variable per experiment. If more than one variable is made different than the control, your experiment is invalid and the information could be considered wrong.
Declare your Dependent Variable
The dependent variable is the way you will measure the results of the experiment.
For the sample experiment, the dependent variable is:
- How long it takes for the sugar cube to completely "disappear" (dissolve).
Describe how the Experiment will be Performed
Your description should be written so that if anyone were to read it, that person would be able to conduct the experiment just the way you did it.
For the sample experiment, the description should go like this:
- In this experiment, I filled two cups with half a cup of distilled water. One cup was measured at approximately seventy five degrees Fahrenheit and the other cup was measured at ninety five degrees Fahrenheit. I dropped a sugar cube in the first cup and started the stopwatch exactly at the same time when the sugar cube touched the water. I repeated the process one more time with the second cup. After the sugar cube completely disappeared, I stopped the stopwatch and recorded my results. I repeated the process one more time with the second cup.
Step 6: Perform the Experiment
All you have to do in this step is perform the experiment exactly as you described in the description in the last step.
Step 7: Collect Data
When you finish timing the first cup, write down your results. Repeat that with the second cup.
Your data collection at this point, doesn't need to be fancy. All this step does is ensure that you know what the data is so you could make it fancy and presentable in the next step with graphs and charts.
For the sample experiment, the data was:
- In the first cup (seventy five degrees Fahrenheit), the sugar cube dissolved in
- In the second cup (ninety five degrees Fahrenheit), the sugar cube dissolved in twenty four minutes and thirty seconds.
Step 8: Conclusions
When you finish collecting your Data, you should now conclude with an analysis of your experiment.
Your analysis should include:
1) Charts and graphs displaying results
2) A sentence/paragraph that states if you accept or reject your hypothesis
3) A summary recapping your experiment (optional)
Charts and Graphs
For the sample experiment, I would recommend using a bar graph.
For the sample experiment, your paragraph should go like this:
- In my experiment, my hypothesis was rejected because the sugar cube dissolved into seventy five degree Fahrenheit water dissolved in less time than the ninety five degree Fahrenheit water.
Step 9: Publishing Findings (optional)
If your experiment was groundbreaking, really interesting or anything along those lines, you might want to consider publishing in a science magazine or journal.