The Scientific Method

The Scientific Method

Middle School

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Learning Objectives

• Define the scientific method and list its steps in the correct order.

• Differentiate between independent, dependent, and controlled variables in an experiment.

• Compare and contrast between qualitative and quantitative types of data.

• Explain the difference between a scientific theory and a scientific law.

Key Vocabulary

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Hypothesis

A testable prediction about the relationship between variables in an experiment.

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Independent Variable

The factor in an experiment that is purposely changed by the scientist.

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Dependent Variable

The factor in an experiment that is measured as it responds to changes.

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Quantitative Data

Information that can be measured or counted and is expressed numerically.

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Qualitative Data

Descriptive information that is gathered by observing with the five senses.

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The Scientific Method

• Ask a question, conduct research, and make observations to understand the problem.

• Formulate a testable hypothesis and test it by conducting a repeatable experiment.

• Record and analyze data to draw a conclusion about your hypothesis.

• Share your results with other scientists for them to review and replicate.

Multiple Choice

Which step in the scientific method involves creating a testable prediction, often in an "If...then..." format?

• Draw a conclusion

• Ask a question

• Formulate a hypothesis

• Conduct research

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Understanding Variables

• A variable is any factor that can be changed or measured in an experiment.

• The independent variable is the one factor a scientist changes on purpose.

• The dependent variable is what you measure to see the effect of the change.

• Controlled variables are kept the same, while the control group gets no treatment.

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Multiple Choice

In an experiment testing how different amounts of water affect plant growth, what is the dependent variable?

• The amount of soil

• The amount of water

• The type of plant

• The plant growth

Data and Graphing

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Quantitative Data

• ​This is data that you can count or measure to get results.

• ​​The results from this type of data are always expressed in numbers.

• ​It is collected using tools like rulers, thermometers, and weighing scales.

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Qualitative Data

• ​This is data used for describing something based on your five senses.

• ​​You can collect this data through observations using your sight or smell.

• ​Examples of this type of data can include color, texture, and smell.

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Graphing Data

• ​Scientists use graphs to display data in a clear, understandable way.

• ​​The independent variable is always plotted on the horizontal X-axis of a graph.

• ​The dependent variable is always plotted on the vertical Y-axis of a graph.

Multiple Choice

When creating a graph of experimental data, where should you place the dependent (responding) variable?

• On the Y-axis

• In the title of the graph

• It does not matter

• On the X-axis

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Scientific Laws vs. Scientific Theories

Scientific Law

• ​Describes a pattern in nature that is based on many observations.

• ​​A law tells you what will happen under certain conditions.

• ​It does not explain the reason why the pattern happens.

Scientific Theory

• ​A well-tested explanation for why something happens in nature.

• ​​It is supported by a broad range of evidence and experiments.

• ​Theories help explain the reason behind a scientific law.

Multiple Choice

What is the primary difference between a scientific law and a scientific theory?

• A law is a guess, while a theory is a fact.

• A theory describes a pattern in nature, while a law explains why it happens.

• A law describes a pattern in nature, while a theory explains why it happens.

• There is no difference between them.

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Common Misconceptions About the Scientific Method

Misconception	Correction
A hypothesis is just a random guess.	It is an educated prediction based on what you already know.
Experiments that don’t support the hypothesis are failures.	All results are valuable and can lead to new questions.
Scientific knowledge is a set of unchanging facts.	It changes as new evidence becomes available.
There is only one single "Scientific Method."	It is a flexible process and can be adapted.

Multiple Choice

Why is it crucial for an experiment to only test one independent variable at a time while keeping all other factors constant?

• To ensure that the results are caused only by the change in the independent variable.

• To allow for more qualitative observations.

• To make the data easier to graph.

• To make the experiment faster to complete.

Multiple Choice

A student hypothesizes, 'If a paper airplane has more weight added to its nose, then it will fly a shorter distance.' What is the dependent variable in this experiment?

• The person throwing the airplane

• The weight added to the nose

• The type of paper used

• The distance the airplane flies

Multiple Choice

A scientist's experiment shows that their data does not support their initial hypothesis. What is the most appropriate next step based on the principles of the scientific method?

• Formulate a new hypothesis based on the collected data and design a new experiment.

• Change the data to match the hypothesis.

• Disregard the results and start a new, unrelated experiment.

• Conclude that the experiment was a complete failure and stop the investigation.

Multiple Choice

Imagine you are investigating if the temperature of a classroom affects student test scores. How would you set up an experiment, identifying the independent, dependent, and at least two controlled variables?

• Change the students in the room (independent) and measure temperature (dependent), keeping the test the same (controlled).

• Change the test difficulty (independent) and measure scores (dependent), keeping temperature and time the same (controlled).

• Change the classroom temperature (independent) and measure test scores (dependent), keeping the test and time limit the same (controlled).

• Change the time of day (independent) and measure classroom temperature (dependent), keeping students and scores the same (controlled).

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Summary

• The scientific method is a step-by-step process for investigations.

• A hypothesis is a testable prediction that guides an experiment.

• Experiments test variables to ensure a fair and controlled study.

• Data can be numbers (quantitative) or descriptions (qualitative).

Poll

On a scale of 1-4, how confident are you about applying the Scientific Method to a problem?

• 1

• 2

• 3

• 4