How to explain controlled variables

Summary

In 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.