# Worksheet: Experimental Measurements

In this worksheet, we will practice recognizing types of experimental variables and how they are used in performing experiments.

Q1:

Which of the following statements most correctly describes the purpose of performing an experiment?

• AAn experiment is performed to confirm a hypothesis.
• BAn experiment is performed to discover new phenomena.
• CAn experiment is performed to test a prediction.
• DAn experiment is performed to generate observations about a known phenomenon.

Q2:

Which of the following statements does not correctly describe why repeating an experiment many times produces more reliable results than a single performance of the experiment?

• AUnknown uncontrolled experimental variables may exist, and if they change independently of any other experimental variables, then their average effect on the dependent variable may be smaller than the effect in any particular single performance of the experiment.
• BRepeating an experiment may be useful in generating ideas for improving the experiment such that the experimental method can be changed to improve it each time the experiment is performed.
• CUnknown uncontrolled experimental variables may exist, and variation in results may show that such variables do, in fact, exist.
• DUnpredictable errors may be made by experimenters while performing experiments.

Q3:

Some experimental variables cannot be controlled and may change in ways that cannot be effectively measured or predicted. One or more of the following statements correctly describes how to perform experimental measurements when unknown uncontrollable variables exist. Which statements are correct?

1. Allow all variables except the independent variable to be dependent variables.
2. Repeat the experiment many times and average the results.
3. Repeat the experiment without changing the value of the independent variable and compare the result of the experiment to the result when the value of the independent variable was changed.
4. Repeat the experiment many times and retain only the results that are consistent with the predictions of the experiment’s hypothesis.
5. Repeat the experiment many times and reject any very anomalous results.
• Aa, b, c, and e
• Ba, b, and d
• Ca, c
• Db, c, and e
• Eb, c, and d

Q4:

Which of the following statements most correctly describes the method for performing an ideal scientific experiment?

• AAll variables should be controlled except for one dependent variable and any independent variables. The values of the independent variables should be changed, and the values of the dependent variable should be measured for each value of each independent variable.
• BAll variables except the independent variable should be controlled, and the values of the independent variable should be measured.
• CAll variables should be controlled except for the independent variable and any dependent variables. The values of the independent variable should be selected, and the values of the dependent variables should be measured for each value of the independent variable.
• DAll variables should be controlled except for one independent variable and one dependent variable. The values of the independent variable should be selected, and the value of the dependent variable should be measured for each value of the independent variable.

Q5:

Which of the following statements most correctly defines a controlled experimental variable?

• AA controlled experimental variable is a quantity that predictably changes in value during an experiment.
• BA controlled experimental variable is a quantity that cannot change in value.
• CA controlled experimental variable is a quantity that does not change in value during an experiment.
• DA controlled experimental variable is a quantity that may unpredictably change in value during an experiment.

Q6:

Which of the following statements most correctly defines an uncontrolled experimental variable?

• AAn uncontrolled experimental variable is a quantity that may unpredictably change in value during an experiment.
• BAn uncontrolled experimental variable is a quantity that cannot change in value.
• CAn uncontrolled experimental variable is a quantity that does not change in value during an experiment.
• DAn uncontrolled experimental variable is a quantity that predictably changes in value during an experiment.

Q7:

Which of the following statements most correctly defines a dependent experimental variable?

• AA dependent experimental variable is a quantity that may unpredictably change in value during an experiment.
• BA dependent experimental variable is a quantity that may change in value during an experiment when an independent variable changes in value.
• CA dependent experimental variable is a quantity that predictably changes in value during an experiment.
• DA dependent experimental variable is a quantity that does not change in value during an experiment.

Q8:

Which of the following statements most correctly defines an independent experimental variable?

• AAn independent experimental variable is a quantity that may unpredictably change in value during an experiment.
• BAn independent experimental variable is a quantity that cannot change in value.
• CAn independent experimental variable is a quantity that predictably changes in value during an experiment.
• DAn independent experimental variable is a quantity that does not change in value during an experiment.

Q9:

Which of the following statements most correctly defines a universal constant?

• AA universal constant is a quantity that cannot change in value, according to a particular scientific model.
• BA universal constant is a quantity that always changes in value by the same amount during an experiment.
• CA universal constant is the average value of a quantity during an experiment.
• DA universal constant is a quantity that does not change in value during an experiment.

Q10:

Which of the following statements most correctly defines a constant?

• AA constant is a quantity that always changes in value by the same amount during an experiment.
• BA constant is a quantity that cannot change in value.
• CA constant is a quantity that does not change in value during an experiment.
• DA constant is the average value of a quantity during an experiment.

Q11:

Which of the following statements most correctly defines an experimental variable?

• AAn experimental variable is a quantity that cannot change in value.
• BAn experimental variable is a quantity that changes in value during an experiment.
• CAn experimental variable is a quantity that may change in value during an experiment.
• DAn experimental variable is a quantity that does not change in value during an experiment.

Q12:

Which of the following statements most correctly defines a measurement value?

• AA measurement value is the number associated with a quantity in a measurement.
• BA measurement value is how useful an experiment is.
• CA measurement value is a measurable property.
• DA measurement value is the amount of something.

Q13:

Which of the following statements most correctly defines a scientific quantity?

• AA quantity is the measured value of a property.
• BA quantity is the amount of something.
• CA quantity is a measurable property.
• DA quantity is an observable property.