How to explain controlled variables

Themantic Education

2 May 202102:39

Summary

TLDRIn this video, an IB psychologist explains the concept of controlled variables in experiments. A controlled variable is something kept constant across both conditions of an experiment to isolate the independent variable's effect. The video emphasizes the importance of controlling variables such as time of day, environment, and materials used, to ensure that differences in results are due to the independent variable alone. The psychologist advises explaining what the controlled variables are, how they were controlled, and why they were controlled to achieve a top-notch explanation.

Takeaways

🔍 A controlled variable is one that you keep constant in both conditions of your experiment to isolate the independent variable as the only factor affecting the results.
☕ Example: To determine if coffee increases energy, you must control other variables like whether or not you do yoga on the same day.
🕒 Controlled variables might include the time of day you conduct the experiment, as this can affect results if not consistent.
🏠 The environment where the experiment is conducted should be consistent, such as doing both tests in rooms with similar lighting and size.
📋 Materials used in the experiment should be consistent, like ensuring word lists in a memory test are of similar length and difficulty.
🤔 If the materials are your independent variable, then the differences in materials are intentional and not controlled.
👥 Controlled variables can also relate to the participants, which will be explained in a future video.
📄 It’s recommended to find two variables that you keep constant in both conditions and explain them clearly.
📝 Use the structure of ‘what, how, and why’ to explain your controlled variables in the experiment for a thorough explanation.
🏅 Providing a detailed explanation of controlled variables is crucial for achieving top marks in your experiment write-up.

Q & A

What is a controlled variable?
-A controlled variable is a variable that is kept constant in both conditions of an experiment to isolate the independent variable as the only factor affecting the results.
Why is it important to control variables in an experiment?
-Controlling variables is important because it ensures that the independent variable is the only factor influencing the outcome, allowing for more accurate conclusions about cause and effect.
Can you give an example of an experiment that demonstrates the importance of controlled variables?
-An example is testing if drinking coffee gives more energy. If one day includes yoga and the other doesn't, then yoga is an uncontrolled variable that could affect the results.
What are some examples of controlled variables in an experiment?
-Examples include the time of day the experiment is conducted, the environment (e.g., room size and lighting), and the materials used (e.g., word lists with similar difficulty).
How can the time of day be a controlled variable in an experiment?
-If one group is tested in the morning and another in the afternoon, differences in results could be due to time of day, making it an extraneous variable. Keeping the testing time consistent controls this variable.
Why is it important to control the environment in an experiment?
-The environment, such as lighting and room size, can influence participants' performance or responses, so it must be controlled to ensure it doesn't affect the results.
How can materials be a controlled variable in an experiment?
-If using two different word lists, they should be similar in difficulty and familiarity unless the word list is the independent variable being tested.
What is the 'what, how, why' method for explaining controlled variables?
-The 'what, how, why' method involves identifying what the controlled variables are, explaining how they are controlled, and describing why controlling them is important for the experiment.
Why might participant-related variables need to be controlled?
-Participant-related variables such as age, gender, and prior knowledge can affect experimental outcomes, so controlling them helps ensure consistent results across different participants.
How can researchers show they have controlled other variables in an experiment?
-Researchers can mention other controlled variables in the experimental setup by referring to specific sections, such as 'see materials' or 'see participants,' to provide more details.

Outlines

00:00

💡 Introduction to Controlled Variables

This paragraph introduces the concept of controlled variables, emphasizing that they must be kept constant in all conditions of an experiment. This allows researchers to isolate the independent variable as the primary factor influencing the results. The speaker prepares to explain controlled variables with an example experiment.

☕ Example: Does Coffee Affect Energy?

Using the example of an experiment testing whether coffee improves energy levels, the speaker explains how controlled variables impact results. On one day, the speaker drinks coffee and feels energized, but they also did yoga, which could affect the outcome. The next day, they only drink water, but without yoga. This highlights the importance of keeping conditions consistent, such as whether yoga is part of the routine, to ensure valid conclusions about coffee’s impact.

🕒 Key Controlled Variables in Experiments

The speaker discusses several key controlled variables that should be considered in an experiment. Factors such as the time of day, environment, and materials used must be consistent. For example, conducting one test in the morning and another in the afternoon, or using different rooms with varied lighting conditions, could introduce unwanted variables that impact results.

📋 Consistency in Materials and Repeated Measures

When using repeated measures, the speaker highlights the importance of maintaining consistency in materials, such as word lists in memory experiments. Different lengths or types of words between groups could skew results. If materials are manipulated as part of the independent variable, it must be clear in the study design. Otherwise, they should remain constant.

👥 Participant-Related Controlled Variables

The speaker hints at another important aspect of controlling variables related to participants. They suggest that controlled variables associated with participant selection and characteristics will be explained in a follow-up video. Ensuring uniformity in participant-related factors is essential for minimizing bias in experiments.

✅ Conclusion: Structuring Your Explanation

To conclude, the speaker offers advice on how to effectively explain controlled variables in an experiment. They suggest focusing on three main points: what the controlled variables are, how they were controlled, and why they were controlled. This clear structure will lead to a strong explanation and help secure top marks in assessments.

Mindmap

Keywords

💡Controlled Variables

Controlled variables are aspects of an experiment that are kept constant across all conditions to ensure that the effects being measured are due to the independent variable. In the video, the psychologist explains that controlled variables help isolate the independent variable as the only factor affecting the results. The example given is doing yoga on one day and not on another, which could affect the outcome of a coffee's effect on energy levels.

💡Independent Variable

The independent variable is the element in an experiment that the researcher manipulates to observe its effect on the dependent variable. In the script, the independent variable is the consumption of coffee, which the researcher is interested in to see if it increases energy levels throughout the day.

💡Dependent Variable

The dependent variable is the outcome or response that is measured in an experiment to see if changes occur due to the manipulation of the independent variable. Although not explicitly mentioned in the transcript, the dependent variable would be the level of energy felt by the researcher, which is measured by a ranking after drinking coffee or water.

💡Experiment

An experiment is a scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact. The video script discusses the process of conducting an experiment to determine if drinking coffee provides more energy, which involves controlling variables to ensure accurate results.

💡Yoga

Yoga is a form of physical, mental, and spiritual discipline that the script uses as an example of a variable that was not controlled in the initial experiment. The psychologist points out that doing yoga on one day and not on another could affect the energy levels felt, thus it should be a controlled variable in a proper experiment.

💡Ranking

Ranking in this context refers to the method of quantifying subjective experiences, such as the level of energy felt throughout the day. The script mentions giving oneself a ranking from one to ten to measure the effect of coffee on energy levels.

💡Extraneous Variables

Extraneous variables are factors outside the main variables of interest that could potentially influence the outcome of an experiment. The video script warns against the influence of extraneous variables such as the time of day or environment in which the experiment is conducted.

💡Environment

Environment, in the context of the video, refers to the physical setting in which the experiment takes place. The psychologist uses the environment as an example of a controlled variable that could affect the outcome if not kept constant, such as conducting the experiment in different rooms with varying lighting or size.

💡Materials

Materials in an experiment refer to the tools, substances, or data used in the process. The script mentions the importance of using the same materials in repeated measures to control for consistency, unless the materials themselves are the subject of manipulation.

💡Repeated Measures

Repeated measures is a type of experimental design where the same participants are tested under different conditions. The video script discusses the need to ensure that the materials used in such designs are consistent, unless they are the independent variable being tested.

💡Participants

Participants are the individuals involved in an experiment, whose responses or behaviors are being studied. The script suggests that aspects related to participants can also be controlled variables, which will be explained in more detail in a subsequent video.

Highlights

A controlled variable is one that remains constant in all conditions of an experiment.

The purpose of controlling variables is to isolate the independent variable's effect on the results.

Example given: Comparing energy levels after drinking coffee versus water to control for the effect of caffeine.

The importance of controlling for extraneous variables such as yoga to ensure the experiment's validity.

Ensuring identical conditions in an experiment except for the manipulated independent variable.

Controlled variables may include the time of day for conducting the experiment.

Environmental factors like room size and lighting can be controlled variables.

Materials used in an experiment, such as word lists, should be consistent unless being manipulated.

The concept of repeated measures and the need for consistency in materials.

Participants' related variables are also important controlled variables in an experiment.

Advice on explaining controlled variables by detailing what, how, and why they were controlled.

Link to a blog for further examples on explaining controlled variables.

The recommendation to find two variables to keep constant for a strong experimental design.

The suggestion to use italics for additional controlled variables not the main focus.

Emphasizing the three steps of explaining controlled variables: what, how, and why.

The promise of achieving top marks by following the advice on explaining controlled variables.

A closing note of encouragement and good luck for the viewer's endeavors.