does the experimental variable change

What are the variables in a science experiment?

What are the Variables in a Science Experiment?

When conducting a science experiment, scientists aim to understand the underlying principles and relationships between variables. A variable is any factor, factor, or condition that can affect the outcome of an experiment. In this article, we will explore the different types of variables, their importance, and how to identify and control them.

Independent Variables

What is an Independent Variable?

An independent variable is a factor that is intentionally changed or manipulated by the experimenter to observe its effect on the dependent variable. This variable is also known as the "cause" or "cause-and-effect" variable. The independent variable is the factor that is being tested or controlled to determine its impact on the outcome of the experiment.

• Example: In a study on the effect of exercise on blood pressure, the independent variable is the amount of exercise, and the dependent variable is blood pressure.

Dependent Variables

What is a Dependent Variable?

A dependent variable is the factor that is being measured or observed in response to changes in the independent variable. This variable is also known as the "effect" or "result" variable. The dependent variable is the outcome or response being measured.

• Example: In the same study on the effect of exercise on blood pressure, the dependent variable is blood pressure.

Control Variables

What are Control Variables?

Control variables are those variables that are not being intentionally changed or manipulated by the experimenter. They are factors that could potentially affect the outcome of the experiment and must be controlled for to ensure the experiment is valid.

• Example: In a study on the effect of a new medication on symptoms of a disease, the control variables include factors such as diet, exercise, and environmental conditions that could also affect the outcome.

Types of Variables

There are several types of variables, including:

• Continuous variables : These variables can take on any value within a specific range, such as temperature or weight.
• Discrete variables : These variables can only take on specific values, such as whole numbers or categorical values, such as male or female.
• Nominal variables : These variables have no inherent scale or measurement, such as eye color or occupation.

Importance of Variables in Science Experiments

Variables play a crucial role in science experiments, as they help to:

• Identify cause-and-effect relationships : By manipulating the independent variable and measuring the resulting change in the dependent variable, scientists can identify the cause-and-effect relationships between variables.
• Test hypotheses : Variables help scientists to test their hypotheses and theories.
• Conduct controlled experiments : By controlling for control variables, scientists can ensure that the experiment is valid and that the results are due to the independent variable and not other factors.

How to Identify and Control Variables

To identify and control variables, scientists use the following steps:

• Conduct a literature review : Review existing research to identify the variables that have been studied previously and how they were controlled.
• Identify the research question : Clearly define the research question and the variables to be studied.
• Design the experimental protocol : Determine the experimental design, including the independent and dependent variables, and the control variables.
• Collect and analyze data : Collect and analyze the data, controlling for significant variables and ensuring that the results are due to the independent variable and not other factors.

In conclusion, variables are a crucial component of science experiments, helping to identify cause-and-effect relationships, test hypotheses, and conduct controlled experiments. By understanding the different types of variables, including independent, dependent, and control variables, scientists can design and conduct experiments that produce reliable and valid results. By following the steps to identify and control variables, scientists can ensure that their experiments are valid and produce meaningful results.

Table: Common Variable Types

Key Takeaways

• Variables are factors that can affect the outcome of a science experiment.
• Independent variables are intentionally changed or manipulated by the experimenter.
• Dependent variables are the outcomes or responses being measured.
• Control variables are factors that could potentially affect the outcome of the experiment.
• Understanding the different types of variables is crucial for designing and conducting effective science experiments.
• How to outline in Google docs?
• How are You supposed to wear AirPods?
• How do I save pics to iCloud?
• How to make Instagram avatar?
• Can You connect a ps4 controller to an iPad?
• How to reboot chrome?
• What is your Instagram handle?
• Is wiley college division 1?

Leave a Comment Cancel Reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Science Notes Posts
• Contact Science Notes
• Todd Helmenstine Biography
• Anne Helmenstine Biography
• Free Printable Periodic Tables (PDF and PNG)
• Periodic Table Wallpapers
• Interactive Periodic Table
• Periodic Table Posters
• Science Experiments for Kids
• How to Grow Crystals
• Chemistry Projects
• Fire and Flames Projects
• Holiday Science
• Chemistry Problems With Answers
• Physics Problems
• Unit Conversion Example Problems
• Chemistry Worksheets
• Biology Worksheets
• Periodic Table Worksheets
• Physical Science Worksheets
• Science Lab Worksheets
• My Amazon Books

Independent and Dependent Variables Examples

The independent and dependent variables are key to any scientific experiment, but how do you tell them apart? Here are the definitions of independent and dependent variables, examples of each type, and tips for telling them apart and graphing them.

Independent Variable

The independent variable is the factor the researcher changes or controls in an experiment. It is called independent because it does not depend on any other variable. The independent variable may be called the “controlled variable” because it is the one that is changed or controlled. This is different from the “ control variable ,” which is variable that is held constant so it won’t influence the outcome of the experiment.

Dependent Variable

The dependent variable is the factor that changes in response to the independent variable. It is the variable that you measure in an experiment. The dependent variable may be called the “responding variable.”

Examples of Independent and Dependent Variables

Here are several examples of independent and dependent variables in experiments:

• In a study to determine whether how long a student sleeps affects test scores, the independent variable is the length of time spent sleeping while the dependent variable is the test score.
• You want to know which brand of fertilizer is best for your plants. The brand of fertilizer is the independent variable. The health of the plants (height, amount and size of flowers and fruit, color) is the dependent variable.
• You want to compare brands of paper towels, to see which holds the most liquid. The independent variable is the brand of paper towel. The dependent variable is the volume of liquid absorbed by the paper towel.
• You suspect the amount of television a person watches is related to their age. Age is the independent variable. How many minutes or hours of television a person watches is the dependent variable.
• You think rising sea temperatures might affect the amount of algae in the water. The water temperature is the independent variable. The mass of algae is the dependent variable.
• In an experiment to determine how far people can see into the infrared part of the spectrum, the wavelength of light is the independent variable and whether the light is observed is the dependent variable.
• If you want to know whether caffeine affects your appetite, the presence/absence or amount of caffeine is the independent variable. Appetite is the dependent variable.
• You want to know which brand of microwave popcorn pops the best. The brand of popcorn is the independent variable. The number of popped kernels is the dependent variable. Of course, you could also measure the number of unpopped kernels instead.
• You want to determine whether a chemical is essential for rat nutrition, so you design an experiment. The presence/absence of the chemical is the independent variable. The health of the rat (whether it lives and reproduces) is the dependent variable. A follow-up experiment might determine how much of the chemical is needed. Here, the amount of chemical is the independent variable and the rat health is the dependent variable.

How to Tell the Independent and Dependent Variable Apart

If you’re having trouble identifying the independent and dependent variable, here are a few ways to tell them apart. First, remember the dependent variable depends on the independent variable. It helps to write out the variables as an if-then or cause-and-effect sentence that shows the independent variable causes an effect on the dependent variable. If you mix up the variables, the sentence won’t make sense. Example : The amount of eat (independent variable) affects how much you weigh (dependent variable).

This makes sense, but if you write the sentence the other way, you can tell it’s incorrect: Example : How much you weigh affects how much you eat. (Well, it could make sense, but you can see it’s an entirely different experiment.) If-then statements also work: Example : If you change the color of light (independent variable), then it affects plant growth (dependent variable). Switching the variables makes no sense: Example : If plant growth rate changes, then it affects the color of light. Sometimes you don’t control either variable, like when you gather data to see if there is a relationship between two factors. This can make identifying the variables a bit trickier, but establishing a logical cause and effect relationship helps: Example : If you increase age (independent variable), then average salary increases (dependent variable). If you switch them, the statement doesn’t make sense: Example : If you increase salary, then age increases.

How to Graph Independent and Dependent Variables

Plot or graph independent and dependent variables using the standard method. The independent variable is the x-axis, while the dependent variable is the y-axis. Remember the acronym DRY MIX to keep the variables straight: D = Dependent variable R = Responding variable/ Y = Graph on the y-axis or vertical axis M = Manipulated variable I = Independent variable X = Graph on the x-axis or horizontal axis

• Babbie, Earl R. (2009). The Practice of Social Research (12th ed.) Wadsworth Publishing. ISBN 0-495-59841-0.
• di Francia, G. Toraldo (1981). The Investigation of the Physical World . Cambridge University Press. ISBN 978-0-521-29925-1.
• Gauch, Hugh G. Jr. (2003). Scientific Method in Practice . Cambridge University Press. ISBN 978-0-521-01708-4.
• Popper, Karl R. (2003). Conjectures and Refutations: The Growth of Scientific Knowledge . Routledge. ISBN 0-415-28594-1.

Related Posts

• Login  /  Register

The largest public health study on obesity in...

Methodologists Oct 21, 2024  0  21295

The World's Most Promising Survey-Based Healt...

Methodologists May 5, 2024  0  21731

Researchers from Saudi Arabia emphasize the s...

Methodologists Jan 4, 2024  0  11470

New Study Highlights the Consumption Patterns...

Methodologists Dec 8, 2023  0  10133

Slimming the Gap: Lifestyle and Dietary Varia...

Methodologists Oct 30, 2023  0  31814

Unlocking the Power of Discourse Analysis

Methodologists Sep 30, 2024  0  10076

Demystifying Participatory Research: A Compre...

Methodologists Sep 19, 2024  0  5758

Leveraging Health Surveillance Systems to Tra...

Methodologists Aug 22, 2024  0  7689

Preparing for Hajj: Medical Requirements and ...

Methodologists Jul 23, 2024  0  7716

How the Fluid Moves Inside Tank Trucks

Methodologists Jan 29, 2024  0  6206

Why Should You Shift your car gear from D to ...

Methodologists Jan 27, 2024  0  6715

Quantum Mechanics: Understanding the Universe...

Methodologists May 31, 2023  0  4269

Applied Mathematics: Bridging the Gap between...

Methodologists May 28, 2023  0  6920

Choosing the Right Path in Criminology and Cr...

Methodologists Jul 24, 2023  0  7519

Understanding the Academic Specialty of Histo...

Methodologists Jul 22, 2023  0  6382

Social Work: Transform Lives, Impact Communities

Methodologists Jul 19, 2023  0  1232

Exploring the Intricate Connections Between P...

Methodologists Jul 18, 2023  0  2779

Dual Representation Theory: A Scientific Pers...

Methodologists Aug 6, 2023  0  11221

Trauma in Transition: The Science and Theorie...

Methodologists Jul 25, 2023  0  4323

How Trauma Shatters Our Worldview: Unmasking ...

Methodologists Jul 21, 2023  0  1500

The Origins of Trauma: A Detailed Examination...

Methodologists Jul 20, 2023  0  2063

Vitamin B1 (Thiamine): Its Importance, Food S...

Methodologists Aug 14, 2023  0  8330

Vitamin A: The Superhero Nutrient Your Body C...

Methodologists Aug 5, 2023  0  9057

Vital Vitamin E: Your Path to Wellness

Methodologists Aug 2, 2023  0  1203

Vitamin C: The Essential Nutrient for Health ...

Methodologists Jul 26, 2023  0  1615

The State of Quantum Computing in 2024: Innov...

Methodologists Dec 21, 2024  0  4062

How to Prepare for Your Menstrual Cycle Every...

Methodologists Dec 16, 2024  0  9587

Why Do Girls Get Periods? The Menstrual Cycle...

Methodologists Dec 15, 2024  0  9337

Why Your Chronic Diarrhea Won’t Stop — And Ho...

Methodologists Dec 8, 2024  0  21996

Innovative Strategies to Combat Traffic Conge...

Methodologists May 15, 2024  0  6723

Sharpen Your Communication Skills: The Impact...

Methodologists Apr 30, 2024  0  14762

Hidden Chemical Additives in Restaurant Food ...

Methodologists Apr 25, 2024  0  6642

New Study Reveals the Impact of Stretch-Focus...

Methodologists Jan 26, 2024  0  5619

Clostridium botulinum and Human Interaction: ...

Methodologists Mar 19, 2024  0  39499

Stuck in Place? The Surprising Power of Weigh...

Methodologists Jan 4, 2024  0  4413

Why We Sleep: The Intriguing Science Behind Y...

Methodologists Aug 20, 2023  0  8293

The ABC of Reproduction: Everything You Need ...

Methodologists Aug 13, 2023  0  8547

Unmasking the Silent Killer in Men: How Menta...

Methodologists Jul 18, 2023  0  1869

Essential Guide to Testicular Care: A Focus o...

Methodologists Jul 16, 2023  0  1285

Surviving the Storm: Unmasking the Realities ...

Methodologists Jul 8, 2023  0  7222

Understanding Men's Mental Health: Confrontin...

Methodologists Jul 5, 2023  0  4007

Body Mysteries for Kids: Journey Through the ...

Methodologists Jan 3, 2024  0  3712

Exciting World of Insects: Entomology for Kids

Methodologists Jan 2, 2024  0  3852

The Art of Engineering: Making and Breaking T...

Methodologists Jan 1, 2024  0  3348

Road Warriors: The Ultimate Vehicles for Post...

Methodologists Jul 14, 2023  0  285

Voices in the Void: Communication in a Post-A...

Methodologists Jul 14, 2023  0  327

Constructing Comfort in Chaos: Shelter Buildi...

Methodologists Jul 14, 2023  0  295

Finding Your Way After the End: Navigating th...

Methodologists Jul 14, 2023  0  177

Comprehensive Analysis of Lyrica's Effect: Fr...

Methodologists Dec 30, 2023  0  4413

Chronic Pain and Beyond: Physiological Effect...

Methodologists Dec 2, 2023  0  16257

The Physiology of Valium Use: From Initial In...

Methodologists Sep 12, 2023  0  13508

Hooked: The Truth Behind Addiction and the 10...

Methodologists Sep 4, 2023  0  397

Unlock the Power of Almonds: Nature's Remedy ...

Methodologists Sep 13, 2023  0  4953

Ashwagandha: The Herbal Supplement Bridging A...

Methodologists Aug 3, 2023  0  16193

The Many Faces of Lemon Balm: Exploring Its B...

Methodologists Jul 31, 2023  0  21493

Honokiol and Magnolia Bark: The Herbal Supple...

Methodologists Jul 31, 2023  0  3439

How 7-9 Hours of Sleep Can Shape Your Longevity

Methodologists Dec 29, 2023  0  10365

Faith, Family, and Friends: The Spiritual Pat...

Methodologists Dec 24, 2023  0  11488

Standing Strong: Integrating Physical Activit...

Methodologists Dec 23, 2023  0  14545

Sauna Sessions: A Warm Way to Ward Off Alzhei...

Methodologists Dec 22, 2023  0  11639

PCOS Girl: It's Time to Fight Back!

Methodologists Dec 25, 2023  0  6489

The Role of Interdisciplinary Collaboration i...

Methodologists Dec 21, 2024  0  5558

Strategies for Youth Development: A Positive ...

Methodologists May 31, 2024  0  7145

Hackathons: Superficial or Substantial for In...

Methodologists May 2, 2024  0  16458

Why is it unethical to clone myself?

Methodologists Mar 3, 2024  0  12016

The Role of Technology in Expanding Access to...

Methodologists Jun 21, 2023  0  6266

The Connection Between Mental Health and Phys...

Methodologists Jun 15, 2023  0  7248

Mental Health Education and Awareness - Empow...

Methodologists Jun 8, 2023  0  5899

The Impact of Mental Health on Social Inclusi...

Methodologists Jun 1, 2023  0  1959

A Comprehensive Guide to Data Governance

Methodologists Jul 9, 2023  0  3413

Playing with Fire: How Social Media Recruitme...

Methodologists Jul 2, 2023  0  15832

Embracing the Future: Data Governance in High...

Methodologists Jul 1, 2023  0  4576

Revolutionizing Research Data Governance: How...

Methodologists Jun 8, 2023  0  8188

Managing Employee-Related Scandals in Media C...

Methodologists Jan 18, 2024  0  6785

Protecting Corporate Reputation: Should Compa...

Methodologists Sep 4, 2023  0  10439

Job Security or Illusion: Are You Replaceable?

Methodologists Jul 15, 2023  0  3678

Are You Good Enough To Be a Leader?

Methodologists Jun 25, 2023  0  3184

The Impact of Digital Culture on Language Dep...

Methodologists Jul 17, 2023  0  6450

The Shift in Reading Culture: How Social Medi...

Methodologists Jul 16, 2023  0  5854

"The Evolution of Human Communication: Emojis...

Methodologists Jul 13, 2023  0  1894

The Revolution of Communication: Analyzing th...

Methodologists Jul 8, 2023  0  12527

The National Biotechnology Strategy: Saudi Ar...

Methodologists Jan 26, 2024  0  7974

Can a Wealthy Country Emerge as a Global Lead...

Methodologists Dec 18, 2023  0  9466

Driving R&D Initiatives with Effective Leader...

Methodologists Dec 9, 2023  0  4046

• Research Highlights
• Navigating the Social Sciences
• Guide to Vitamins and Minerals
• Trauma: From Concepts to Healing
• Exploring Engineering
• Unmasking Drug Addiction
• Mystery Science
• Essentials of Human Biology
• Women Health
• Nature's Remedies: Herbal Supplements
• Strategies to survive any apocalypse
• Men's Health Insights
• Science Behind Everyday Life
• Lifespan Determinants: Empirical Insights into the Science of Longevity
• Innovation Management
• Contemporary Organizational Behavior
• Research Data Governance in Universities and Research Institutions
• Hashtag vs Handshake
• 2023 World Mental Health Day

Join Our Newsletter

Join our subscribers list to get the latest news, updates and special offers directly in your inbox

Variables in Research: Breaking Down the Essentials of Experimental Design

Understanding the role of variables in research is essential for designing and conducting experiments that produce accurate and reliable results. learn about the different types of variables and how they are used in experimental design, with examples of independent and dependent variables.

Unraveling the life sciences: The Fascinating Secrets of Everyday Life

Understanding population in scientific research: a comprehensive breakdown for r..., what's your reaction.

Related Posts

Ethnography: A Comprehensive Guide for Qualitative Rese...

Methodologists Sep 11, 2023  0  11117

Connecting the Dots: A Guide to Understanding Causality...

Methodologists May 22, 2023  0  2001

No Treatment? No Problem: The Science Behind Control Gr...

Methodologists Jul 17, 2023  0  4394

Popular Posts

Why Your Chronic Diarrhea Won’t Stop — And How SIB...

Exploring Narrative Research: A Comprehensive Guid...

Methodologists Sep 14, 2023  0  20899

Ethnography: A Comprehensive Guide for Qualitative...

How to Prepare for Your Menstrual Cycle Every Mont...

Why Do Girls Get Periods? The Menstrual Cycle Expl...

Recommended posts.

Shedding the Weight, Adding the Years: How Obesity...

Methodologists Dec 4, 2023  0  7889

Revolutionizing Research Collaboration: Emerging T...

Methodologists Dec 2, 2023  0  6326

Applying the Scientific Method in Innovation Manag...

Methodologists Nov 1, 2023  0  13689

The Methodologists - Science PodCasts

Methodologists Jul 26, 2023  0  372

Popular Tags

• Mental Health
• behavioral science
• weight loss
• MENTAL HEALTH IS A UNIVERSAL HUMAN RIGHT

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies.

What Are Dependent, Independent & Controlled Variables?

Say you're in lab, and your teacher asks you to design an experiment. The experiment must test how plants grow in response to different colored light. How would you begin? What are you changing? What are you keeping the same? What are you measuring?

These parameters of what you would change and what you would keep the same are called variables. Take a look at how all of these parameters in an experiment are defined, as independent, dependent and controlled variables.

What Is a Variable?

A variable is any quantity that you are able to measure in some way. This could be temperature, height, age, etc. Basically, a variable is anything that contributes to the outcome or result of your experiment in any way.

In an experiment there are multiple kinds of variables: independent, dependent and controlled variables.

What Is an Independent Variable?

An independent variable is the variable the experimenter controls. Basically, it is the component you choose to change in an experiment. This variable is not dependent on any other variables.

For example, in the plant growth experiment, the independent variable is the light color. The light color is not affected by anything. You will choose different light colors like green, red, yellow, etc. You are not measuring the light.

What Is a Dependent Variable?

A dependent variable is the measurement that changes in response to what you changed in the experiment. This variable is dependent on other variables; hence the name! For example, in the plant growth experiment, the dependent variable would be plant growth.

You could measure this by measuring how much the plant grows every two days. You could also measure it by measuring the rate of photosynthesis. Either of these measurements are dependent upon the kind of light you give the plant.

What Are Controlled Variables?

A control variable in science is any other parameter affecting your experiment that you try to keep the same across all conditions.

For example, one control variable in the plant growth experiment could be temperature. You would not want to have one plant growing in green light with a temperature of 20°C while another plant grows in red light with a temperature of 27°C.

You want to measure only the effect of light, not temperature. For this reason you would want to keep the temperature the same across all of your plants. In other words, you would want to control the temperature.

Another example is the amount of water you give the plant. If one plant receives twice the amount of water as another plant, there would be no way for you to know that the reason those plants grew the way they did is due only to the light color their received.

The observed effect could also be due in part to the amount of water they got. A control variable in science experiments is what allows you to compare other things that may be contributing to a result because you have kept other important things the same across all of your subjects.

Graphing Your Experiment

When graphing the results of your experiment, it is important to remember which variable goes on which axis.

The independent variable is graphed on the x-axis . The dependent variable , which changes in response to the independent variable, is graphed on the y-axis . Controlled variables are usually not graphed because they should not change. They could, however, be graphed as a verification that other conditions are not changing.

For example, after graphing the growth as compared to light, you could also look at how the temperature varied across different conditions. If you notice that it did vary quite a bit, you may need to go back and look at your experimental setup: How could you improve the experiment so that all plants are exposed to as similar an environment as possible (aside from the light color)?

How to Remember Which is Which

In order to try and remember which is the dependent variable and which is the independent variable, try putting them into a sentence which uses "causes a change in."

Here's an example. Saying, "light color causes a change in plant growth," is possible. This shows us that the independent variable affects the dependent variable. The inverse, however, is not true. "Plant growth causes a change in light color," is not possible. This way you know which is the independent variable and which is the dependent variable!

• NCES Kids: What are Independent and Dependent Variables?
• Khan Academy: Dependent and independent variables review (article)

Cite This Article

Gupta, Riti. "What Are Dependent, Independent & Controlled Variables?" sciencing.com , https://www.sciencing.com/dependent-independent-controlled-variables-8360093/. 10 February 2020.

Gupta, Riti. (2020, February 10). What Are Dependent, Independent & Controlled Variables?. sciencing.com . Retrieved from https://www.sciencing.com/dependent-independent-controlled-variables-8360093/

Gupta, Riti. What Are Dependent, Independent & Controlled Variables? last modified March 24, 2022. https://www.sciencing.com/dependent-independent-controlled-variables-8360093/

Recommended

• Science, Tech, Math ›
• Chemistry ›

What Is a Variable in Science?

Understanding Variables in a Science Experiment

• Chemical Laws
• Periodic Table
• Projects & Experiments
• Scientific Method
• Biochemistry
• Physical Chemistry
• Medical Chemistry
• Chemistry In Everyday Life
• Famous Chemists
• Activities for Kids
• Abbreviations & Acronyms
• Weather & Climate
• Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
• B.A., Physics and Mathematics, Hastings College

Variables are an important part of science projects and experiments. What is a variable? Basically, a variable is any factor that can be controlled, changed, or measured in an experiment. Scientific experiments have several types of variables. The independent and dependent variables are the ones usually plotted on a chart or graph, but there are other types of variables you may encounter.

Types of Variables

• Independent Variable: The independent variable is the one condition that you change in an experiment. Example: In an experiment measuring the effect of temperature on solubility, the independent variable is temperature.
• Dependent Variable: The dependent variable is the variable that you measure or observe. The dependent variable gets its name because it is the factor that is dependent on the state of the independent variable . Example: In the experiment measuring the effect of temperature on solubility, solubility would be the dependent variable.
• Controlled Variable: A controlled variable or constant variable is a variable that does not change during an experiment. Example : In the experiment measuring the effect of temperature on solubility, controlled variable could include the source of water used in the experiment, the size and type of containers used to mix chemicals, and the amount of mixing time allowed for each solution.
• Extraneous Variables: Extraneous variables are "extra" variables that may influence the outcome of an experiment but aren't taken into account during measurement. Ideally, these variables won't impact the final conclusion drawn by the experiment, but they may introduce error into scientific results. If you are aware of any extraneous variables, you should enter them in your lab notebook . Examples of extraneous variables include accidents, factors you either can't control or can't measure, and factors you consider unimportant. Every experiment has extraneous variables. Example : You are conducting an experiment to see which paper airplane design flies longest. You may consider the color of the paper to be an extraneous variable. You note in your lab book that different colors of papers were used. Ideally, this variable does not affect your outcome.

Using Variables in Science Experiment

In a science experiment , only one variable is changed at a time (the independent variable) to test how this changes the dependent variable. The researcher may measure other factors that either remain constant or change during the course of the experiment but are not believed to affect its outcome. These are controlled variables. Any other factors that might be changed if someone else conducted the experiment but seemed unimportant should also be noted. Also, any accidents that occur should be recorded. These are extraneous variables.

Variables and Attributes

In science, when a variable is studied, its attribute is recorded. A variable is a characteristic, while an attribute is its state. For example, if eye color is the variable, its attribute might be green, brown, or blue. If height is the variable, its attribute might be 5 m, 2.5 cm, or 1.22 km.

• Earl R. Babbie. The Practice of Social Research , 12th edition. Wadsworth Publishing, 2009.
• What Is a Dependent Variable?
• What Is an Experiment? Definition and Design
• Six Steps of the Scientific Method
• Examples of Independent and Dependent Variables
• How To Design a Science Fair Experiment
• The Role of a Controlled Variable in an Experiment
• Scientific Variable
• What Are the Elements of a Good Hypothesis?
• Dependent Variable vs. Independent Variable: What Is the Difference?
• What Is the Difference Between a Control Variable and Control Group?
• Independent Variable Definition and Examples
• Null Hypothesis Examples
• What Is a Controlled Experiment?
• DRY MIX Experiment Variables Acronym
• Scientific Method Vocabulary Terms
• What Is the Difference Between Hard and Soft Science?

• Activities, Experiments, Online Games, Visual Aids
• Activities, Experiments, and Investigations
• Experimental Design and the Scientific Method

Experimental Design - Independent, Dependent, and Controlled Variables

Scientific experiments are meant to show cause and effect of a phenomena (relationships in nature).  The “ variables ” are any factor, trait, or condition that can be changed in the experiment and that can have an effect on the outcome of the experiment.

An experiment can have three kinds of variables: i ndependent, dependent, and controlled .

• The independent variable is one single factor that is changed by the scientist followed by observation to watch for changes. It is important that there is just one independent variable, so that results are not confusing.
• The dependent variable is the factor that changes as a result of the change to the independent variable.
• The controlled variables (or constant variables) are factors that the scientist wants to remain constant if the experiment is to show accurate results. To be able to measure results, each of the variables must be able to be measured.

For example, let’s design an experiment with two plants sitting in the sun side by side. The controlled variables (or constants) are that at the beginning of the experiment, the plants are the same size, get the same amount of sunlight, experience the same ambient temperature and are in the same amount and consistency of soil (the weight of the soil and container should be measured before the plants are added). The independent variable is that one plant is getting watered (1 cup of water) every day and one plant is getting watered (1 cup of water) once a week. The dependent variables are the changes in the two plants that the scientist observes over time.

Can you describe the dependent variable that may result from this experiment? After four weeks, the dependent variable may be that one plant is taller, heavier and more developed than the other. These results can be recorded and graphed by measuring and comparing both plants’ height, weight (removing the weight of the soil and container recorded beforehand) and a comparison of observable foliage.

Using What You Learned: Design another experiment using the two plants, but change the independent variable. Can you describe the dependent variable that may result from this new experiment?

Think of another simple experiment and name the independent, dependent, and controlled variables. Use the graphic organizer included in the PDF below to organize your experiment's variables.

High Resolution Version for Printing

Citing research references.

When you research information you must cite the reference. Citing for websites is different from citing from books, magazines and periodicals. The style of citing shown here is from the MLA Style Citations (Modern Language Association).

When citing a WEBSITE the general format is as follows. Author Last Name, First Name(s). "Title: Subtitle of Part of Web Page, if appropriate." Title: Subtitle: Section of Page if appropriate. Sponsoring/Publishing Agency, If Given. Additional significant descriptive information. Date of Electronic Publication or other Date, such as Last Updated. Day Month Year of access < URL >.

Here is an example of citing this page:

Amsel, Sheri. "Experimental Design - Independent, Dependent, and Controlled Variables" Exploring Nature Educational Resource ©2005-2024. December 24, 2024 < http://www.exploringnature.org/db/view/Experimental-Design-Independent-Dependent-and-Controlled-Variables >

Exploringnature.org has more than 2,000 illustrated animals. Read about them, color them, label them, learn to draw them.

“The mission of Ranger College is to transform lives and give students the skills to be a positive influence in their communities.”

• Oil Exhibit
• Digital Repository
• Library Events
• Purchase Suggestions
• Scientific Method
• What is scientific research
• Qualitative vs. Quantitative

Independent and Dependent Variables

In an experiment, the independent variable is the variable that is varied or manipulated by the researcher.

The dependent variable is the response that is measured.   One way to think about it is that the dependent variable depends on the change in the independent variable.  In theory, a change in the independent variable will lead to a change in the dependent variable.

In a study of how different doses of a drug affect the severity of symptoms, a researcher could compare the frequency and intensity of symptoms when different doses are administered.

Here the independent variable is the dose and the dependent variable is the frequency/intensity of symptoms .

The rudder on a boat directs the course of the boat.  By changing the position of the rudder (turning it left or right), the rudder moves a certain way in the water, and that movement changes the trajectory of the boat.  

Here the independent variable is the rudder , while the dependent variable is the trajectory of the boat.

Tips: 

Independent and dependent variables are often referred to in other ways.  For instance, independent variables are sometimes called experimental variables or predictor variables.  Dependent variables are sometimes called outcome variables.

One way to differentiate between whether a variable is independent or dependent is to consider when each variable occurred.  Typically, the independent variable will be the variable that happened earlier. Meaning, if I am looking at a dataset that has a variable for the year someone was born and a variable for their level of happiness in 2019, it’s a good bet that the birth year is the independent variable because it happened before the current measure of happiness in 2019 (assuming we are not surveying newborn babies). In effect, this question would be measuring whether someone’s year of birth (maybe translated as generation affiliation) relates to how happy they are in 2019.

• << Previous: Qualitative vs. Quantitative
• Last Updated: Aug 16, 2021 1:10 PM
• URL: https://library.rangercollege.edu/scientificmethod