Scientific Method & Laboratory Observations – Chemistry Lab Intro

Question-and-Answer flashcards covering the scientific method, quantitative vs. qualitative observations, data recording practices, hypotheses, experiments, laws, theories, and measurement concepts from the chemistry lab introduction.

What is the first step in any version of the scientific method?

Making an observation (gathering data from nature).

What three simplified steps of the scientific method did the lecturer emphasize?

Observation → Hypothesis → Experiment (test/prediction).

Which two broad categories do laboratory observations fall into?

Quantitative observations (measurements) and qualitative observations (descriptive).

What defines a quantitative observation?

A measurement that includes a numerical value, an appropriate unit, and an associated uncertainty.

Why is it meaningless to record a number without a unit?

Because the unit tells what the number represents; without it the measurement has no context.

What is ‘uncertainty’ in a measurement?

The degree of doubt in the reading, often indicated by how many decimal places the instrument reliably provides.

List four common quantities chemists measure in lab.

Length, mass, temperature, and volume.

What is a qualitative observation?

Non-numerical descriptive information about the quality of a substance, such as color, odor, or physical state.

Give an example of temperature stated qualitatively versus quantitatively.

“It’s warm” (qualitative) versus “82.7 °F” (quantitative).

In the lecturer’s lab, how must primary data be recorded?

Directly in the lab notebook/data table, in non-erasable blue or black ink.

Why does the instructor forbid recording primary data in pencil?

Pencil can be erased and altered later, compromising the integrity of the data.

What is a hypothesis?

A testable proposed explanation for an observation.

Why does working with hypotheses require ‘thick skin’?

Because hypotheses are often proven wrong and must be refined or discarded repeatedly.

What is the purpose of an experiment in the scientific method?

To test the predictions derived from a hypothesis and generate new data.

What happens if experimental results do not match the prediction?

The hypothesis is rejected or refined, and the cycle starts again with a new prediction and test.

When can a hypothesis be upgraded to a theory?

After extensive, repeated testing shows it consistently explains a broad range of observations.

How does a scientific law differ from a theory?

A law summarizes consistent observations without necessarily explaining why; a theory provides an explanatory framework supported by evidence.

Name one scientific law mentioned in the lecture.

The law of conservation of mass (e.g., 20 g of reactants yield 20 g of products).

Why must scientists avoid bias during experiments?

Bias can distort observations and conclusions; objective data are essential to sound science.

What is the difference between accuracy and precision?

Accuracy is closeness to the true value; precision is the repeatability or consistency of measurements.

According to the lecturer, at what academic level do students typically begin designing their own experiments?

Junior–senior (upper-division) university courses.

What did the lecturer note about the pace of scientific learning today?

It is accelerating rapidly; more information has been gathered in the last decade than in the previous century.