Repetition and Replication

Repetition and Replication

Middle School

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Learning Objectives

• Define and differentiate between repetition and replication in scientific investigations.

• Explain why repetition is crucial for ensuring the reliability of experimental data.

• Explain why replication is essential for establishing the validity of scientific conclusions.

• Analyze scenarios to correctly identify whether they describe repetition or replication.

Key Vocabulary

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Repetition

A scientist repeats their own experiment many times to make sure the results are accurate and reliable.

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Replication

A different scientist recreates an experiment to check if the original findings and conclusions are correct.

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Reliable Results

Reliable results are consistent outcomes from an experiment repeated multiple times by the same scientist.

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Validity

Validity is how accurate an experiment's conclusions are, supported by results that have been replicated.

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Repetition vs. Replication

Repetition

• The same scientist repeats an experiment multiple times to ensure the results are reliable.

• This helps verify the accuracy of the data by collecting more information.

• For example, you fly a paper airplane ten times to record its flight distance.

Replication

• A different scientist conducts an experiment that was designed and done by someone else.

• The goal is to follow the original procedures to confirm the experiment's validity.

• For example, you build and test a water filter using your friend's exact instructions.

Multiple Choice

Hannah conducted an experiment and performed multiple trials. Then, Angel followed Hannah's exact procedure to conduct the same experiment. Which statement correctly describes their actions?

• Both Hannah and Angel performed repetition.

• Hannah replicated her experiment, and Angel repeated it.

• Both Hannah and Angel performed replication.

• Hannah repeated her experiment, and Angel replicated it.

The Importance of Retesting

• Retesting experiments is crucial for verifying the scientific results.

• Many trials are conducted to make sure the results are reliable.

• Other scientists replicate experiments to ensure the conclusions are valid.

Multiple Choice

What is the primary reason for another scientist to replicate an experiment?

• To find flaws in the original scientist's hypothesis.

• To help the original scientist perform multiple trials.

• To confirm the validity of the original experiment’s conclusions.

• To create a new experiment based on the original one.

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Common Misconceptions About Scientific Investigations

Misconception	Correction
Retesting your own experiment is replication.	This is repetition. Replication is when another scientist retests your experiment.
Repetition and replication are the same thing.	Repetition is multiple trials by one person. Replication is another person redoing the experiment.
One successful trial is enough if your hypothesis is supported.	Many trials are needed to ensure results are reliable, not just a coincidence.

Multiple Choice

Karis returns to Sarasota Bay each week for 4 weeks and collects 5 water samples to test during a Red Tide Event. Why is this action important in a scientific investigation?

• It allows another scientist to check her work for validity.

• It is repetition, which helps ensure her results are reliable.

• It is part of forming a new hypothesis about Red Tide events.

• It represents replication, which proves her hypothesis is valid.

Multiple Choice

Bobby tests if new running shoes help runners run faster by having five runners each run three times with old shoes and three times with new shoes. His colleague, Billy, then gets Bobby's procedure and conducts the exact same test with different runners. What is the relationship between their actions?

• Both scientists performed replication to ensure validity.

• Bobby performed repetition for reliability, and Billy performed replication for validity.

• Bobby performed replication for validity, and Billy performed repetition for reliability.

• Bobby's test is the conclusion, and Billy's test is the hypothesis.

Multiple Choice

A student discovers that mixing glue and borax creates a new substance that glows. To ensure this discovery is accepted by the scientific community, what is the most critical sequence of actions to take?

• Repeat the experiment multiple times for reliability, publish the procedure, then have other scientists replicate it for validity.

• Have other scientists replicate the experiment first for validity, then the original student repeats it for reliability.

• Publish the results immediately, then have others replicate it for validity.

• Form a new hypothesis, repeat the experiment once, and then have a friend replicate it.

Multiple Choice

Imagine a study claims that remote controls in hotel rooms are very dirty. The hotel CEO has her own team test rooms in her hotels (repetition), while a journalist contacts the original study's author to get the procedure and re-run the test (replication). What outcome would most strongly challenge the original study's findings?

• The CEO's team finds all the hotel rooms are clean.

• The original study author refuses to share the procedure.

• The CEO and the journalist both find that the rooms are dirty.

• The journalist's replication finds that the remote controls are not the dirtiest item.

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Summary

• The same scientist repeats trials to ensure results are reliable.

• A different scientist replicates an experiment to confirm its validity.

• Both are essential for creating strong and accepted scientific conclusions.

• Valid experiments must be designed to be retestable by others.

Poll

How confident are you in differentiating between repetition and replication?

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