Controls and Variables in Scientific Experiments
Explore the fundamental concepts of independent, dependent, and controlled variables in scientific experimentation, crucial for Grade 12 science students.
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Controls and Variables in Scientific Experiments
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Read each question carefully and provide concise, accurate answers based on your understanding of scientific controls and variables.
1. In an experiment to test the effect of fertilizer on plant growth, what is the independent variable?
Amount of water
Type of plant
Amount of fertilizer
Plant height
2. Which of the following best describes a controlled variable?
The variable that is changed by the experimenter.
The variable that is measured or observed.
A variable kept constant to ensure a fair test.
The outcome of the experiment.
3. The variable that is deliberately changed by the scientist in an experiment is called the variable.
4. The group in an experiment does not receive the treatment and is used for comparison.
5. A good scientific experiment should only have one variable to ensure valid results.
6. Design a simple experiment to test if playing classical music improves student concentration during a test. Identify the independent, dependent, and at least two controlled variables.
7. Explain why it is crucial to have controlled variables in a scientific experiment.
Analyze the following experiment:
A scientist wants to determine if a new type of fertilizer (Fertilizer X) increases the yield of corn crops. She sets up two identical fields. Field A receives Fertilizer X, while Field B receives no fertilizer. Both fields are exposed to the same amount of sunlight, receive the same amount of water, and are planted with the same corn variety. After the growing season, the corn yield (in bushels per acre) is measured for both fields.
8. What is the independent variable in this experiment?
9. What is the dependent variable in this experiment?
10. List three controlled variables in this experiment.
11. A control group is always exposed to the independent variable.
True
False
12. The dependent variable is the cause, and the independent variable is the effect.
True
False
Observe the scientific setup below and answer the questions.
13. If this setup is used to separate pigments from a plant extract, what would be the independent variable if you were testing different types of solvents?
14. What would be a likely dependent variable to measure in such an experiment?