Scientific Method Steps: Problem, Hypothesis, Experiment & Data Analysis in Biology

Scientific Method

An organised way of solving problems and answering questions about the world.

Steps of the Scientific Method

A set of flexible steps that scientists can adapt depending on what they are studying.

Define the problem / aim

What question are you trying to answer?

Collect information / make observations

What do you already know? What background research is needed?

Form a hypothesis

Make a testable prediction.

Experiment

Design and carry out a fair test.

Collect results / data

Record your measurements or observations.

Conclusion

Explain what the results show, and whether they support your hypothesis.

Repeat

Repeat the experiment (or refine it) to check reliability.

Problem

What are we trying to find out? Usually based on observations and stated as a question.

Example of Problem

Does temperature affect the rate of cricket chirps?

Collect Information About the Problem

Information can be gathered from your own observations, published research articles, reliable internet sources, and textbooks.

Good Hypothesis

A good hypothesis is one that can be tested by experimentation.

Hypothesis

An educated or plausible guess, based on a question.

Useful Hypothesis

A useful hypothesis will enable predictions.

Prediction

A specific forecast about a future event.

Formal Hypothesis

A formal hypothesis used in an experiment should be stated in If...then... because... form.

Example of Formal Hypothesis

If the temperature of the cricket enclosure is increased then they will chirp more because higher temperatures cause muscle contractions.

Controlled Experiment

An experiment must be controlled and test only one thing at a time.

Control Group

The control group provides a normal standard against which the scientist can compare results of the experimental group.

Experimental Group

The experimental group is identical to the control group except for the one factor being tested.

Independent Variable

The variable being tested is the independent variable.

Dependent Variable

The variable being measured is the dependent variable.

Control Variables

The variables kept the same are the control variables.

Experimental Design

Needs to be repeatable (can be repeated exactly).

Sample Size

Should test a large sample.

Bias

Should be without bias (Limit any form of racial, financial, personal, religious, social investment).

Variable

Anything that can change in an experiment.

Controlled Variables

What is kept the same?

Independent Variables

What is changed? (Manipulated variables)

Dependent Variables

What is measured? (Responding variables)

Data

Observations or measurements.

Quantitative Data

Number data; Example: 10 chirps per minute.

Qualitative Data

Observations; Example: the crickets became more active.

Processed Data

Summarizes and organizes raw data, making the meaning of the data more clear.

Graph Title

Should be clear, concise, and show the relationship between the variables.

Graphing Tip

IV on X-axis, DV on Y-axis, title = 'Effect of [IV] on [DV]' with units and title on both axes.

PEE Conclusion Template

Point: The experiment showed that as _______ changed, _______ also changed. Evidence: (MUST USE DATA) For example, when _______ was (high/low/increased/decreased/number), the results showed _______. Explain: This happened because _______. The science behind this is that _______.

Theory

A hypothesis that has been tested repeatedly and shown to be correct becomes a theory.

Examples of Theories

Germ Theory of Disease, Plate Tectonics Theory, Big Bang Theory, Theory of Relativity.