Uncertainties in measurements: chemistry | Starter Quiz | Oak National Academy

Which piece(s) of laboratory equipment are typically used for measuring volume?

• Graduated cylinder (measuring cylinder)

• Balance

• Pipette

• Ruler

Answer explanation

A balance is used to measure mass, not volume. A ruler measures distance.

Which mathematical operation(s) would you use to calculate the average of three measurements?

• Addition

• Subtraction

• Multiplication

• Division

Answer explanation

To calculate the average (mean), you would add up all the measurements and then divide by the number of measurements.

In an experiment, what type of variable is the one that the scientist changes?

• Independent variable

• Dependent variable

• Control variable

• Uncontrolled variable

Answer explanation

The independent variable is the one that is changed or controlled by the scientist to observe its effect on the dependent variable.

In an experiment measuring the effect of sunlight on plant growth, what is the dependent variable?

• The type of plant.

• The amount of water given to each plant.

• The height of the plant.

• The amount of sunlight each plant receives.

Answer explanation

The height of the plant is the dependent variable, as it changes in response to the amount of sunlight received, which is the independent variable.

Significant ___ refer to the digits in a measurement that are known with certainty plus the first digit that is uncertain.

Answer explanation

Significant figures refer to the digits in a measurement that are known with certainty plus the first digit that is uncertain.

Match the following terms with their correct definitions:

• Accuracy

• An error that has an equal probability of being too high or too low.

• Precision

• The degree to which a measurement reflects the true value.

• Random Error

• The closeness of two or more measurements to each other.

• Control Variable

• A variable that is kept constant throughout an experiment.

Answer explanation

Random error affects measurements unpredictably. Precision indicates how close measurements are to each other. Accuracy measures how close a measurement is to the true value. A control variable is kept constant to ensure the experiment's fairness.