set up the experiment

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How to Conduct a Science Experiment

Last Updated: December 14, 2024 Fact Checked

This article was co-authored by Meredith Juncker, PhD . Meredith Juncker is a PhD candidate in Biochemistry and Molecular Biology at Louisiana State University Health Sciences Center. Her studies are focused on proteins and neurodegenerative diseases. There are 10 references cited in this article, which can be found at the bottom of the page. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 198,204 times.

Experimentation is the method by which scientists test natural phenomena in the hopes of gaining new knowledge.. Good experiments follow a logical design to isolate and test specific, precisely-defined variables. By learning the fundamental principles behind experimental design, you'll be able to apply these principles to your own experiments. Regardless of their scope, all good experiments operate according to the logical, deductive principles of the scientific method, from fifth-grade potato clock science fair projects to cutting-edge Higgs Boson research. [1] X Research source

Designing a Scientifically Sound Experiment

• For instance, if you want to do an experiment on agricultural fertilizer, don't seek to answer the question, "Which kind of fertilizer is best for growing plants?" There are many different types of fertilizer and many different kinds of plants in the world - one experiment won't be able to draw universal conclusions about either. A much better question to design an experiment around would be "What concentration of nitrogen in fertilizer produces the largest corn crops?"
• Modern scientific knowledge is very, very vast. If you intend to do serious scientific research, research your topic extensively before you even begin to plan your experiment. Have past experiments answered the question you want your experiment to study? If so, is there a way to adjust your topic so that it addresses questions left unanswered by existing research?

• For instance, in our fertilizer experiment example, our scientist would grow multiple corn crops in soil supplemented with fertilizers whose nitrogen concentration differs. He would give each corn crop the exact same amount of fertilizer. He would make sure the chemical composition of his fertilizers used did not differ in some way besides its nitrogen concentration - for instance, he would not use a fertilizer with a higher concentration of magnesium for one of his corn crops. He would also grow the exact same number and species of corn crops at the same time and in the same type of soil in each replication of his experiment.

• Typically, a hypothesis is expressed as a quantitative declarative sentence. A hypothesis also takes into account the ways that the experimental parameters will be measured. A good hypothesis for our fertilizer example is: "Corn crops supplemented with 1 pound of nitrogen per bushel will result in a greater yield mass than equivalent corn crops grown with differing nitrogen supplements."

• Timing is incredibly important, so stick to your plan as close as possible. That way, if you see changes in your results, you can rule out different time constraints as the cause of the change.
• Making a data table beforehand is a great idea - you'll be able to simply insert your data values into the table as you record them.
• Know the difference between your dependent and independent variables. An independent variable is a variable that you change and a dependent variable is the one affected by the independent variable. In our example, "nitrogen content" is the independent variable, and "yield (in kg)" is the dependent variable. A basic table will have columns for both variables as they change over time.

• Good experimental design incorporates what's known as a control. One of your experimental replications should not include the variable you're testing for at all. In our fertilizer example, we'll include one corn crop which receives a fertilizer with no nitrogen in it. This will be our control - it will be the baseline against which we'll measure the growth of our other corn crops.
• Observe any and all safety measures associated with hazardous materials or processes in your experiment. [6] X Research source

• It's always a good idea to represent your data visually if you can. Plot data points on a graph and express trends with a line or curve of best fit. This will help you (and anyone else who sees the graph) visualize patterns in the data. For most basic experiments, the independent variable is represented on the horizontal x axis and the dependent variable is on the vertical y axis.

• To share your results, write a comprehensive scientific paper. Knowing how to write a scientific paper is a useful skill - the results of most new research must be written and published according to a specific format, often dictated by the style guide for a relevant, peer-reviewed academic journal.

Running an Example Experiment

• In this case, the type of aerosol fuel we use is the independent variable (the variable we change), while the range of the projectile is the dependent variable.
• Things to consider for this experiment - is there a way to ensure each potato projectile has the same weight? Is there a way to administer the same amount of aerosol fuel for each firing? Both of these can potentially affect the range of the gun. Weigh each projectile beforehand and fuel each shot with the same amount of aerosol spray.

• The furthest-left column will be labeled "Trial #." The cells in this column will simply contain the numbers 1-10, signifying each firing attempt.
• The following four columns will be labeled with the names of the aerosol sprays we're using in our experiment. The ten cells beneath each column header will contain the range (in meters) of each firing attempt.
• Below the four columns for each fuel, leave a space to write the average value of the ranges.

• Like many experiments, our experiment has certain safety concerns we need to observe. The aerosol fuels we're using are flammable - we should be sure to close the potato gun's firing cap securely and to wear heavy gloves while igniting the fuel. To avoid accidental injuries from the projectiles, we should also make sure that we (and any observers) are standing to the side of the gun as it fires - not in front of it or behind it.

• We can even share our results with the world in the form of a scientific paper - given the subject matter of our experiment, it may be more appropriate to present this information in the form of a tri-fold science fair display.

Community Q&A

• In upper-level sciences, most data isn't used unless it is reproducible at least 3 times. Thanks Helpful 0 Not Helpful 1
• Science is about asking big questions. Don't be afraid to choose a topic you haven't looked at before. Thanks Helpful 0 Not Helpful 0
• Have fun and stay safe. Thanks Helpful 0 Not Helpful 0

• Wear eye protection Thanks Helpful 29 Not Helpful 1
• Wash your hands before and after an experiment. Thanks Helpful 29 Not Helpful 3
• Do not have any food or drinks near your workstation. Thanks Helpful 25 Not Helpful 5
• If anything gets in your eyes rinse them out thoroughly with water for 15 minutes, then seek immediate medical attention. Thanks Helpful 7 Not Helpful 0
• Tie loose hair back Thanks Helpful 23 Not Helpful 7
• Wear rubber gloves when handling chemicals Thanks Helpful 23 Not Helpful 8
• When using sharp knives, dangerous chemicals, or hot flames, make sure you have an adult supervising you at all times. Thanks Helpful 15 Not Helpful 4

You Might Also Like

• ↑ https://www.khanacademy.org/science/high-school-biology/hs-biology-foundations/hs-biology-and-the-scientific-method/a/experiments-and-observations
• ↑ https://www.sciencebuddies.org/science-fair-projects/project-ideas/list
• ↑ https://www.sciencebuddies.org/science-fair-projects/science-fair/variables
• ↑ https://www.livescience.com/21490-what-is-a-scientific-hypothesis-definition-of-hypothesis.html
• ↑ https://sciencing.com/collect-data-science-project-5988780.html
• ↑ https://ehsdailyadvisor.blr.com/2012/04/11-rules-for-safe-handling-of-hazardous-materials/
• ↑ https://www.sciencebuddies.org/science-fair-projects/science-fair/conducting-an-experiment
• ↑ https://www.sciencebuddies.org/science-fair-projects/science-fair/writing-a-hypothesis
• ↑ https://www.sciencebuddies.org/science-fair-projects/science-fair/steps-of-the-scientific-method
• ↑ https://www.sciencebuddies.org/science-fair-projects/science-fair/data-analysis-graphs

About This Article

If you want to conduct a science experiment, first come up with a question you want to answer, then devise a way to test that question. Make sure you have a control, or an untested component to your experiment. For example, if you want to find out which fertilizer is best for growing crops, you would have one plant for each type of fertilizer, plus one plant that doesn’t get any fertilizer. Write down each step of your experiment carefully, along with the final result. For tips on organizing your data collection, read on! Did this summary help you? Yes No

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How to Conduct Experiments Using the Scientific Method

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 T estable 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 Hypothesis as 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, the Hypothesis can 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.

Rejecting/Accepting Hypothesis

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.

How To Set Up A Controlled Science Experiment

How to Setup a Controlled Science Experiment. To setup a controlled science experiment, one must have a good understanding of the scientific method. The scientific method is a process, a set of guidelines, used to ensure the accuracy of the experiment, thus achieving "control." If one fails to follow the scientific method, a controlled experiment is impossible, and the results of the experiment are worthless.

Setup a Controlled Science Experiment Utilizing the Scientific Method

Begin by doing your research. Research is necessary to gather data that is used to formulate a hypothesis and to create the experiment.

Identify a problem. The problem is the question you are trying to answer. Without a problem, there is no reason for experimentation.

Formulate a hypothesis. The hypothesis is a statement, based on your research, that is intended to provide a solution to the problem. The hypothesis is what you are trying to prove or disprove.

Conduct your experiment to prove the hypothesis. A controlled science experiment is setup to test whether a variable has a direct causal relationship on another.

Identify your independent and dependent variables. The independent variable is commonly known as the cause, while the dependent variable is the effect. For example, in the statement A causes B, A is the independent variable and B is the dependent. A controlled scientific experiment can only measure one variable at a time. If more than one variable is manipulated, it is impossible to say for certain which caused the end result and the experiment is invalidated.

Do not alter your hypothesis midway through the experiment. The setup of a controlled scientific experiment must be constant. You can not make changes once you have begun, even if the results you are getting do not seem to support your original hypothesis. When you change your hypothesis, you change the entire experiment and you must begin again.

Do not be upset if your results are not what you expect. Some of the greatest scientific advances have come from experiments that disproved the original hypothesis.

Start over again with a new hypothesis or find new variables to manipulate. Scientific advancement is a painstakingly slow process and scientists often spend years and even an entire lifetime working on the same problem.

Failure to follow the scientific method precisely will invalidate all results of the experiment.

Cite This Article

Contributor, . "How To Set Up A Controlled Science Experiment" sciencing.com , https://www.sciencing.com/setup-controlled-science-experiment-2044405/. 21 July 2017.

Contributor, . (2017, July 21). How To Set Up A Controlled Science Experiment. sciencing.com . Retrieved from https://www.sciencing.com/setup-controlled-science-experiment-2044405/

Contributor, . How To Set Up A Controlled Science Experiment last modified August 30, 2022. https://www.sciencing.com/setup-controlled-science-experiment-2044405/

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Exploring the Art of Experimental Design: A Step-by-Step Guide for Students and Educators

Experimental design for students.

Experimental design is a key method used in subjects like biology, chemistry, physics, psychology, and social sciences. It helps us figure out how different factors affect what we're studying, whether it's plants, chemicals, physical laws, human behavior, or how society works. Basically, it's a way to set up experiments so we can test ideas, see what happens, and make sense of our results. It's super important for students and researchers who want to answer big questions in science and understand the world better. Experimental design skills can be applied in situations ranging from problem solving to data analysis; they are wide reaching and can frequently be applied outside the classroom. The teaching of these skills is a very important part of science education, but is often overlooked when focused on teaching the content. As science educators, we have all seen the benefits practical work has for student engagement and understanding. However, with the time constraints placed on the curriculum, the time needed for students to develop these experimental research design and investigative skills can get squeezed out. Too often they get a ‘recipe’ to follow, which doesn’t allow them to take ownership of their practical work. From a very young age, they start to think about the world around them. They ask questions then use observations and evidence to answer them. Students tend to have intelligent, interesting, and testable questions that they love to ask. As educators, we should be working towards encouraging these questions and in turn, nurturing this natural curiosity in the world around them.

Teaching the design of experiments and letting students develop their own questions and hypotheses takes time. These materials have been created to scaffold and structure the process to allow teachers to focus on improving the key ideas in experimental design. Allowing students to ask their own questions, write their own hypotheses, and plan and carry out their own investigations is a valuable experience for them. This will lead to students having more ownership of their work. When students carry out the experimental method for their own questions, they reflect on how scientists have historically come to understand how the universe works.

Take a look at the printer-friendly pages and worksheet templates below!

What are the Steps of Experimental Design?

Embarking on the journey of scientific discovery begins with mastering experimental design steps. This foundational process is essential for formulating experiments that yield reliable and insightful results, guiding researchers and students alike through the detailed planning, experimental research design, and execution of their studies. By leveraging an experimental design template, participants can ensure the integrity and validity of their findings. Whether it's through designing a scientific experiment or engaging in experimental design activities, the aim is to foster a deep understanding of the fundamentals: How should experiments be designed? What are the 7 experimental design steps? How can you design your own experiment?

This is an exploration of the seven key experimental method steps, experimental design ideas, and ways to integrate design of experiments. Student projects can benefit greatly from supplemental worksheets and we will also provide resources such as worksheets aimed at teaching experimental design effectively. Let’s dive into the essential stages that underpin the process of designing an experiment, equipping learners with the tools to explore their scientific curiosity.

1. Question

This is a key part of the scientific method and the experimental design process. Students enjoy coming up with questions. Formulating questions is a deep and meaningful activity that can give students ownership over their work. A great way of getting students to think of how to visualize their research question is using a mind map storyboard.

Ask students to think of any questions they want to answer about the universe or get them to think about questions they have about a particular topic. All questions are good questions, but some are easier to test than others.

2. Hypothesis

A hypothesis is known as an educated guess. A hypothesis should be a statement that can be tested scientifically. At the end of the experiment, look back to see whether the conclusion supports the hypothesis or not.

Forming good hypotheses can be challenging for students to grasp. It is important to remember that the hypothesis is not a research question, it is a testable statement . One way of forming a hypothesis is to form it as an “if... then...” statement. This certainly isn't the only or best way to form a hypothesis, but can be a very easy formula for students to use when first starting out.

An “if... then...” statement requires students to identify the variables first, and that may change the order in which they complete the stages of the visual organizer. After identifying the dependent and independent variables, the hypothesis then takes the form if [change in independent variable], then [change in dependent variable].

For example, if an experiment were looking for the effect of caffeine on reaction time, the independent variable would be amount of caffeine and the dependent variable would be reaction time. The “if, then” hypothesis could be: If you increase the amount of caffeine taken, then the reaction time will decrease.

3. Explanation of Hypothesis

What led you to this hypothesis? What is the scientific background behind your hypothesis? Depending on age and ability, students use their prior knowledge to explain why they have chosen their hypotheses, or alternatively, research using books or the internet. This could also be a good time to discuss with students what a reliable source is.

For example, students may reference previous studies showing the alertness effects of caffeine to explain why they hypothesize caffeine intake will reduce reaction time.

4. Prediction

The prediction is slightly different to the hypothesis. A hypothesis is a testable statement, whereas the prediction is more specific to the experiment. In the discovery of the structure of DNA, the hypothesis proposed that DNA has a helical structure. The prediction was that the X-ray diffraction pattern of DNA would be an X shape.

Students should formulate a prediction that is a specific, measurable outcome based on their hypothesis. Rather than just stating "caffeine will decrease reaction time," students could predict that "drinking 2 cans of soda (90mg caffeine) will reduce average reaction time by 50 milliseconds compared to drinking no caffeine."

5. Identification of Variables

Below is an example of a Discussion Storyboard that can be used to get your students talking about variables in experimental design.

The three types of variables you will need to discuss with your students are dependent, independent, and controlled variables. To keep this simple, refer to these as "what you are going to measure", "what you are going to change", and "what you are going to keep the same". With more advanced students, you should encourage them to use the correct vocabulary.

Dependent variables are what is measured or observed by the scientist. These measurements will often be repeated because repeated measurements makes your data more reliable.

The independent variables are variables that scientists decide to change to see what effect it has on the dependent variable. Only one is chosen because it would be difficult to figure out which variable is causing any change you observe.

Controlled variables are quantities or factors that scientists want to remain the same throughout the experiment. They are controlled to remain constant, so as to not affect the dependent variable. Controlling these allows scientists to see how the independent variable affects the dependent variable within the experimental group.

Use this example below in your lessons, or delete the answers and set it as an activity for students to complete on Storyboard That.

6. Risk Assessment

Ultimately this must be signed off on by a responsible adult, but it is important to get students to think about how they will keep themselves safe. In this part, students should identify potential risks and then explain how they are going to minimize risk. An activity to help students develop these skills is to get them to identify and manage risks in different situations. Using the storyboard below, get students to complete the second column of the T-chart by saying, "What is risk?", then explaining how they could manage that risk. This storyboard could also be projected for a class discussion.

7. Materials

In this section, students will list the materials they need for the experiments, including any safety equipment that they have highlighted as needing in the risk assessment section. This is a great time to talk to students about choosing tools that are suitable for the job. You are going to use a different tool to measure the width of a hair than to measure the width of a football field!

8. General Plan and Diagram

It is important to talk to students about reproducibility. They should write a procedure that would allow their experimental method to be reproduced easily by another scientist. The easiest and most concise way for students to do this is by making a numbered list of instructions. A useful activity here could be getting students to explain how to make a cup of tea or a sandwich. Act out the process, pointing out any steps they’ve missed.

For English Language Learners and students who struggle with written English, students can describe the steps in their experiment visually using Storyboard That.

Not every experiment will need a diagram, but some plans will be greatly improved by including one. Have students focus on producing clear and easy-to-understand diagrams that illustrate the experimental group.

For example, a procedure to test the effect of sunlight on plant growth utilizing completely randomized design could detail:

• Select 10 similar seedlings of the same age and variety
• Prepare 2 identical trays with the same soil mixture
• Place 5 plants in each tray; label one set "sunlight" and one set "shade"
• Position sunlight tray by a south-facing window, and shade tray in a dark closet
• Water both trays with 50 mL water every 2 days
• After 3 weeks, remove plants and measure heights in cm

9. Carry Out Experiment

Once their procedure is approved, students should carefully carry out their planned experiment, following their written instructions. As data is collected, students should organize the raw results in tables, graphs, photos or drawings. This creates clear documentation for analyzing trends.

Some best practices for data collection include:

• Record quantitative data numerically with units
• Note qualitative observations with detailed descriptions
• Capture set up through illustrations or photos
• Write observations of unexpected events
• Identify data outliers and sources of error

For example, in the plant growth experiment, students could record:

They would also describe observations like leaf color change or directional bending visually or in writing.

It is crucial that students practice safe science procedures. Adult supervision is required for experimentation, along with proper risk assessment.

Well-documented data collection allows for deeper analysis after experiment completion to determine whether hypotheses and predictions were supported.

Completed Examples

Resources and Experimental Design Examples

Using visual organizers is an effective way to get your students working as scientists in the classroom.

There are many ways to use these investigation planning tools to scaffold and structure students' work while they are working as scientists. Students can complete the planning stage on Storyboard That using the text boxes and diagrams, or you could print them off and have students complete them by hand. Another great way to use them is to project the planning sheet onto an interactive whiteboard and work through how to complete the planning materials as a group. Project it onto a screen and have students write their answers on sticky notes and put their ideas in the correct section of the planning document.

Very young learners can still start to think as scientists! They have loads of questions about the world around them and you can start to make a note of these in a mind map. Sometimes you can even start to ‘investigate’ these questions through play.

The foundation resource is intended for elementary students or students who need more support. It is designed to follow exactly the same process as the higher resources, but made slightly easier. The key difference between the two resources are the details that students are required to think about and the technical vocabulary used. For example, it is important that students identify variables when they are designing their investigations. In the higher version, students not only have to identify the variables, but make other comments, such as how they are going to measure the dependent variable or utilizing completely randomized design. As well as the difference in scaffolding between the two levels of resources, you may want to further differentiate by how the learners are supported by teachers and assistants in the room.

Students could also be encouraged to make their experimental plan easier to understand by using graphics, and this could also be used to support ELLs.

Students need to be assessed on their science inquiry skills alongside the assessment of their knowledge. Not only will that let students focus on developing their skills, but will also allow them to use their assessment information in a way that will help them improve their science skills. Using Quick Rubric , you can create a quick and easy assessment framework and share it with students so they know how to succeed at every stage. As well as providing formative assessment which will drive learning, this can also be used to assess student work at the end of an investigation and set targets for when they next attempt to plan their own investigation. The rubrics have been written in a way to allow students to access them easily. This way they can be shared with students as they are working through the planning process so students know what a good experimental design looks like.

Printable Resources

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Related Activities

Additional Worksheets

If you're looking to add additional projects or continue to customize worksheets, take a look at several template pages we've compiled for you below. Each worksheet can be copied and tailored to your projects or students! Students can also be encouraged to create their own if they want to try organizing information in an easy to understand way.

• Lab Worksheets
• Discussion Worksheets
• Checklist Worksheets

Related Resources

• Scientific Method Steps
• Science Discussion Storyboards
• Developing Critical Thinking Skills

How to Teach Students the Design of Experiments

Encourage questioning and curiosity.

Foster a culture of inquiry by encouraging students to ask questions about the world around them.

Formulate testable hypotheses

Teach students how to develop hypotheses that can be scientifically tested. Help them understand the difference between a hypothesis and a question.

Provide scientific background

Help students understand the scientific principles and concepts relevant to their hypotheses. Encourage them to draw on prior knowledge or conduct research to support their hypotheses.

Identify variables

Teach students about the three types of variables (dependent, independent, and controlled) and how they relate to experimental design. Emphasize the importance of controlling variables and measuring the dependent variable accurately.

Plan and diagram the experiment

Guide students in developing a clear and reproducible experimental procedure. Encourage them to create a step-by-step plan or use visual diagrams to illustrate the process.

Carry out the experiment and analyze data

Support students as they conduct the experiment according to their plan. Guide them in collecting data in a meaningful and organized manner. Assist them in analyzing the data and drawing conclusions based on their findings.

Frequently Asked Questions about Experimental Design for Students

What are some common experimental design tools and techniques that students can use.

Common experimental design tools and techniques that students can use include random assignment, control groups, blinding, replication, and statistical analysis. Students can also use observational studies, surveys, and experiments with natural or quasi-experimental designs. They can also use data visualization tools to analyze and present their results.

How can experimental design help students develop critical thinking skills?

Experimental design helps students develop critical thinking skills by encouraging them to think systematically and logically about scientific problems. It requires students to analyze data, identify patterns, and draw conclusions based on evidence. It also helps students to develop problem-solving skills by providing opportunities to design and conduct experiments to test hypotheses.

How can experimental design be used to address real-world problems?

Experimental design can be used to address real-world problems by identifying variables that contribute to a particular problem and testing interventions to see if they are effective in addressing the problem. For example, experimental design can be used to test the effectiveness of new medical treatments or to evaluate the impact of social interventions on reducing poverty or improving educational outcomes.

What are some common experimental design pitfalls that students should avoid?

Common experimental design pitfalls that students should avoid include failing to control variables, using biased samples, relying on anecdotal evidence, and failing to measure dependent variables accurately. Students should also be aware of ethical considerations when conducting experiments, such as obtaining informed consent and protecting the privacy of research subjects.

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Home » Experimental Design – Types, Methods, Guide

Experimental Design – Types, Methods, Guide

Table of Contents

Experimental design is a structured approach used to conduct scientific experiments. It enables researchers to explore cause-and-effect relationships by controlling variables and testing hypotheses. This guide explores the types of experimental designs, common methods, and best practices for planning and conducting experiments.

Experimental Design

Experimental design refers to the process of planning a study to test a hypothesis, where variables are manipulated to observe their effects on outcomes. By carefully controlling conditions, researchers can determine whether specific factors cause changes in a dependent variable.

Key Characteristics of Experimental Design :

• Manipulation of Variables : The researcher intentionally changes one or more independent variables.
• Control of Extraneous Factors : Other variables are kept constant to avoid interference.
• Randomization : Subjects are often randomly assigned to groups to reduce bias.
• Replication : Repeating the experiment or having multiple subjects helps verify results.

Purpose of Experimental Design

The primary purpose of experimental design is to establish causal relationships by controlling for extraneous factors and reducing bias. Experimental designs help:

• Test Hypotheses : Determine if there is a significant effect of independent variables on dependent variables.
• Control Confounding Variables : Minimize the impact of variables that could distort results.
• Generate Reproducible Results : Provide a structured approach that allows other researchers to replicate findings.

Types of Experimental Designs

Experimental designs can vary based on the number of variables, the assignment of participants, and the purpose of the experiment. Here are some common types:

1. Pre-Experimental Designs

These designs are exploratory and lack random assignment, often used when strict control is not feasible. They provide initial insights but are less rigorous in establishing causality.

• Example : A training program is provided, and participants’ knowledge is tested afterward, without a pretest.
• Example : A group is tested on reading skills, receives instruction, and is tested again to measure improvement.

2. True Experimental Designs

True experiments involve random assignment of participants to control or experimental groups, providing high levels of control over variables.

• Example : A new drug’s efficacy is tested with patients randomly assigned to receive the drug or a placebo.
• Example : Two groups are observed after one group receives a treatment, and the other receives no intervention.

3. Quasi-Experimental Designs

Quasi-experiments lack random assignment but still aim to determine causality by comparing groups or time periods. They are often used when randomization isn’t possible, such as in natural or field experiments.

• Example : Schools receive different curriculums, and students’ test scores are compared before and after implementation.
• Example : Traffic accident rates are recorded for a city before and after a new speed limit is enforced.

4. Factorial Designs

Factorial designs test the effects of multiple independent variables simultaneously. This design is useful for studying the interactions between variables.

• Example : Studying how caffeine (variable 1) and sleep deprivation (variable 2) affect memory performance.
• Example : An experiment studying the impact of age, gender, and education level on technology usage.

5. Repeated Measures Design

In repeated measures designs, the same participants are exposed to different conditions or treatments. This design is valuable for studying changes within subjects over time.

• Example : Measuring reaction time in participants before, during, and after caffeine consumption.
• Example : Testing two medications, with each participant receiving both but in a different sequence.

Methods for Implementing Experimental Designs

• Purpose : Ensures each participant has an equal chance of being assigned to any group, reducing selection bias.
• Method : Use random number generators or assignment software to allocate participants randomly.
• Purpose : Prevents participants or researchers from knowing which group (experimental or control) participants belong to, reducing bias.
• Method : Implement single-blind (participants unaware) or double-blind (both participants and researchers unaware) procedures.
• Purpose : Provides a baseline for comparison, showing what would happen without the intervention.
• Method : Include a group that does not receive the treatment but otherwise undergoes the same conditions.
• Purpose : Controls for order effects in repeated measures designs by varying the order of treatments.
• Method : Assign different sequences to participants, ensuring that each condition appears equally across orders.
• Purpose : Ensures reliability by repeating the experiment or including multiple participants within groups.
• Method : Increase sample size or repeat studies with different samples or in different settings.

Steps to Conduct an Experimental Design

• Clearly state what you intend to discover or prove through the experiment. A strong hypothesis guides the experiment’s design and variable selection.
• Independent Variable (IV) : The factor manipulated by the researcher (e.g., amount of sleep).
• Dependent Variable (DV) : The outcome measured (e.g., reaction time).
• Control Variables : Factors kept constant to prevent interference with results (e.g., time of day for testing).
• Choose a design type that aligns with your research question, hypothesis, and available resources. For example, an RCT for a medical study or a factorial design for complex interactions.
• Randomly assign participants to experimental or control groups. Ensure control groups are similar to experimental groups in all respects except for the treatment received.
• Randomize the assignment and, if possible, apply blinding to minimize potential bias.
• Follow a consistent procedure for each group, collecting data systematically. Record observations and manage any unexpected events or variables that may arise.
• Use appropriate statistical methods to test for significant differences between groups, such as t-tests, ANOVA, or regression analysis.
• Determine whether the results support your hypothesis and analyze any trends, patterns, or unexpected findings. Discuss possible limitations and implications of your results.

Examples of Experimental Design in Research

• Medicine : Testing a new drug’s effectiveness through a randomized controlled trial, where one group receives the drug and another receives a placebo.
• Psychology : Studying the effect of sleep deprivation on memory using a within-subject design, where participants are tested with different sleep conditions.
• Education : Comparing teaching methods in a quasi-experimental design by measuring students’ performance before and after implementing a new curriculum.
• Marketing : Using a factorial design to examine the effects of advertisement type and frequency on consumer purchase behavior.
• Environmental Science : Testing the impact of a pollution reduction policy through a time series design, recording pollution levels before and after implementation.

Experimental design is fundamental to conducting rigorous and reliable research, offering a systematic approach to exploring causal relationships. With various types of designs and methods, researchers can choose the most appropriate setup to answer their research questions effectively. By applying best practices, controlling variables, and selecting suitable statistical methods, experimental design supports meaningful insights across scientific, medical, and social research fields.

• Campbell, D. T., & Stanley, J. C. (1963). Experimental and Quasi-Experimental Designs for Research . Houghton Mifflin Company.
• Shadish, W. R., Cook, T. D., & Campbell, D. T. (2002). Experimental and Quasi-Experimental Designs for Generalized Causal Inference . Houghton Mifflin.
• Fisher, R. A. (1935). The Design of Experiments . Oliver and Boyd.
• Field, A. (2013). Discovering Statistics Using IBM SPSS Statistics . Sage Publications.
• Cohen, J. (1988). Statistical Power Analysis for the Behavioral Sciences . Routledge.

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