Enriched Chemistry
Chapter Two – Measurements and Calculations
Section 1 – Scientific Method
scientific method – a logical approach to solving problems by observing and collecting data, formulating hypotheses, testing hypotheses, and formulating theories that are supported by data.
- An organized system of answering scientific questions.
- We do this every day when we problem solve.
- It’s also only occasionally done in real science investigations
Although there are many variations of the scientific method, they all contain the same basic elements:
Step One – make an observation.
Step Two – state the problem or ask a question.
Step Three – make one or more testable hypotheses.
- hypothesis – an educated guess.
Step Four – design an experiment and test the hypotheses.
Step Five – analyze the results and draw conclusions.
- Decide if your hypothesis is correct or incorrect, and make adjustments.
Scientific investigations rely on making good observations.
Observing is the use of senses to obtain information.
- data may be quantitative or qualitative
quantitative is numerical info, i.e. 25.7 grams
qualitative is descriptive, i.e. the chemical smelled like sulfur
Parts of a good controlled experiment:
- hypotheses – a testable statement.
- controls – the experimental conditions that remain constant throughout an experiment.
- variable – any condition that changes during an experiment
- independent variable – what is being altered by the experimenter
- dependent variable – the results.
Some misc. terms you should know:
system – a set of interacting or interdependent components that can be studied together
model – an explanation of how phenomena occur and how data or events are related
- often used to study things that are too small, too large, or too dangerous to study in real life
theory – a broad generalization that explains a body of facts or phenomena
- These may change as new information is discovered.
examples: big bang theory, evolution
scientific law – a rule that describes but doesn’t explain a pattern in nature and predicts what will happen under certain conditions.
examples: law of gravity, law of conservation of mass
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