Question

for each experiment below, specify the independent variable, dependent variable, control group and any constants. 1. a student wanted to test how the mass of a paper airplane affected the distance it would fly. paper clips were added before each test flight. as each paper clip was added, the plane was tested to determine how far it would fly. independent variable dependent variable control constants 2. two groups of students were tested to compare their speed working math problems. each group was given the same problems. one group used calculators and the other group computed without calculators. independent variable dependent variable control constant 3. students of different ages were given the same puzzle to assemble. the puzzle assembly time was measured. independent variable dependent variable constant 4. an experiment was performed to determine how the amount of coffee grounds could affect the taste of coffee. the same kind of coffee, the same percolator, the same amount and type of water, the same perking time, and the same electrical sources were used. there can be several controlled variables. if an experiment is to be useful, only one variable at a time can be manipulated intentionally. all other variables must be controlled throughout all parts of the experiment. if more than one variable is altered (changed), the results of an experiment cannot be interpreted with any validity.

Explanation:

1. In the paper - airplane experiment:

• The independent variable is the mass (number of paper - clips added).
• The dependent variable is the distance the paper airplane flies.
• The control group is the paper airplanes without any added paper - clips.
• Constants are the type of paper, the way of folding the airplane, etc.

1. In the math - problem experiment:

• The independent variable is the use of calculators (using calculators or not).
• The dependent variable is the speed of working on math problems.
• The control group is the group without calculators.
• Constants are the same problems given to both groups, the same time limit (if any), etc.

1. In the puzzle - assembly experiment:

• The independent variable is the age of students.
• The dependent variable is the puzzle - assembly time.
• The control group is not clearly defined in a traditional sense here as there is no comparison group with a different treatment for the age variable in a typical control - experimental setup. But if we consider all students as part of the experiment, constants could be the same puzzle, same environment, etc.

1. In the coffee - taste experiment:

• The independent variable is not clearly stated but could be factors like brewing time if we assume other factors are constant.
• The dependent variable is the taste of coffee.
• The control group is not clearly defined. Constants are the same kind of coffee, same percolator, same electrical sources, same amount and type of water, etc.

Answer:

1. Independent variable: Mass of paper - clips added; Dependent variable: Distance the paper airplane flies; Control group: Paper airplanes without added paper - clips; Constants: Type of paper, folding method.
2. Independent variable: Use of calculators; Dependent variable: Speed of working on math problems; Control group: Group without calculators; Constants: Problems given, time limit (if any).
3. Independent variable: Age of students; Dependent variable: Puzzle - assembly time; Control group: Not clearly defined; Constants: Puzzle, environment.
4. Independent variable: Brewing time (assumed); Dependent variable: Taste of coffee; Control group: Not clearly defined; Constants: Coffee type, percolator, water amount and type, electrical source.