Question

Use what you know about the vocabulary words to explain the differences between the words in the following sets. Then explain how the words are related. $$ \text { independent variable-constant } $$

Short answer

Independent variables change; constants do not. They ensure experiments are fair.

Step-by-step solution

Define Independent Variable

An independent variable is a variable that is manipulated or controlled in an experiment to test its effects on dependent variables. It is what you change in an experiment to see how it affects other variables.

Define Constant

A constant is a factor that does not change and remains fixed throughout the experiment. Constants are used to ensure that the effect on the dependent variable is solely due to the independent variable, not other factors.

Describe Differences

The primary difference is that the independent variable can be changed or controlled, whereas a constant remains unchanged and stable throughout the experimental process.

Explain Relationship

In an experiment, independent variables are manipulated while keeping constants stable to observe their effect on dependent variables. They are related because constants need to be managed alongside independent variables to conduct a fair test in an experiment.

Key concepts

Independent Variables

Independent variables are a fundamental part of scientific experimentation. When conducting an experiment, the independent variable is the one you have control over. This is the variable that you will intentionally change to see what effect it has.
For example, if you were testing the effect of sunlight on plant growth, the amount of sunlight the plants receive would be your independent variable. You might choose to give one plant 4 hours of sunlight, another 6 hours, and another 8 hours. By doing this, you are manipulating the amount of sunlight each plant gets to determine how it impacts growth.
Remember, there can be only one independent variable in an experiment, as having more than one would make it difficult to determine which one is causing the observed change in the dependent variable.

Constants in Experiments

In every well-designed experiment, constants play a critical role. A constant is something that remains the same throughout the entire experiment.
These are the factors you don’t change, no matter what happens. They help ensure that any changes in the dependent variable are truly due to the effects of the independent variable and not some other factor.
Consider the plant growth example again. While you are varying the amount of sunlight, perhaps you keep factors such as the type of plant, the amount of water, and the type of soil exactly the same. These are your constants. By keeping them stable, you can be confident that any differences in growth are due to the amount of sunlight each plant received.

• Constants act as a control that balance the experiment.
• They allow for a fair test, providing reliable and valid results.

Dependent Variables

Dependent variables are what you measure in the experiment. They are called "dependent" because their changes depend on variations in the independent variable.
Returning to our plant growth study, the dependent variable here could be the height of the plants or the number of leaves. As you change the amount of sunlight (your independent variable), you measure "how much the plants grow" to see what happens.
It is crucial to think about how you will measure your dependent variables. Consistent measurement is key for seeing if your independent variable is actually having any effect.

• Identify one clear dependent variable to focus your investigation.
• Ensure measurements are accurate and consistent for reliable results.

Experimental Design

Experimental design is the blueprint for conducting your experiment. It coordinates all the elements of your experiment into a cohesive strategy.
A well-thought-out experimental design will include:

• Clear Hypothesis: What you expect to happen and why.
• Identification of Variables: Properly identifying your independent variable, dependent variable, and constants.
• Procedures: Detailed steps of how the experiment will be conducted.
• Reproducibility: Ensuring others can replicate your experiment to verify your results.

By carefully designing your experiment, you can ensure your conclusions are valid and based on clear, measurable evidence. This enhances the reliability of your findings and helps to better understand the relationship between the independent variables and the dependent ones.