Unit 10 — Scientific Inquiry, Laboratory Safety, and Experimental Design

Welcome to Grade 6 Science!

Science is a method of discovering how the natural world works.

Scientists ask questions, make observations, design investigations, analyze evidence, and share what they learn with others.

Scientific knowledge grows through careful testing, honest reporting, and continual investigation.

Today you will strengthen your understanding of the scientific method and learn how to work safely in a laboratory.

What Is Scientific Inquiry?

Scientific inquiry is the process of investigating questions using observation, evidence, experimentation, and logical reasoning.

Scientists do not simply accept ideas because someone says they are true.

Instead, they ask:

• What evidence supports this?
• Can it be tested?
• Can the results be repeated?
• Does the evidence support the conclusion?

Scientific inquiry encourages curiosity while requiring careful reasoning.

Observation and Inference

Scientists make careful observations.

An observation describes something detected using the senses or measuring instruments.

Examples include:

• temperature
• color
• length
• mass
• sound
• motion

An inference is a logical conclusion based on observations and prior knowledge.

Observations provide evidence.

Inferences explain what the evidence may mean.

Asking Testable Questions

A good scientific question should be:

• clear
• specific
• measurable
• testable

Examples include:

• How does temperature affect the rate at which ice melts?
• Does the amount of sunlight affect plant growth?
• Which material provides the best insulation?

Questions that cannot be tested scientifically require other methods of investigation.

Developing a Hypothesis

A hypothesis is a testable explanation or prediction.

Example:

"If plants receive more hours of sunlight each day, then they will grow taller because sunlight provides energy for photosynthesis."

A hypothesis should be based on observations and existing knowledge.

It should be possible to test whether it is supported by evidence.

Variables

Experiments usually involve three kinds of variables.

Independent Variable

The factor that the scientist changes.

Dependent Variable

The factor that is measured.

Controlled Variables

The conditions that remain the same so the test is fair.

Keeping variables under control improves the reliability of an experiment.

Laboratory Safety

Safety is always the first priority.

Laboratory rules include:

• follow instructions carefully
• wear safety equipment when required
• handle chemicals responsibly
• report accidents immediately
• keep work areas organized
• never taste unknown substances
• use equipment only as instructed
• wash hands after experiments

Responsible behavior protects everyone in the laboratory.

Recording Data

Scientists record observations carefully.

Useful tools include:

• notebooks
• tables
• graphs
• photographs
• diagrams
• digital sensors

Accurate records allow others to understand and repeat an investigation.

Drawing Conclusions

After collecting data, scientists ask:

• Was the hypothesis supported?
• Were the results consistent?
• Could another explanation exist?
• What sources of error may have influenced the investigation?
• What questions remain?

Scientific conclusions should always be based on evidence.

Communicating Results

Scientists share discoveries through:

• laboratory reports
• presentations
• scientific journals
• diagrams
• graphs
• discussions

Clear communication allows other scientists to review, repeat, and expand upon previous work.

Activity

Design an investigation.

Include:

• a scientific question
• a hypothesis
• independent, dependent, and controlled variables
• materials
• procedure
• safety precautions
• data table
• graph
• conclusion

Explain how another student could repeat your investigation.

Practice

Answer these questions.

What is scientific inquiry?

How is an observation different from an inference?

What makes a question testable?

What is a hypothesis?

What are independent and dependent variables?

Why is laboratory safety important?

Review

Today you learned:

• science depends on evidence and investigation
• observations and inferences serve different purposes
• hypotheses are testable explanations
• experiments require careful control of variables
• laboratory safety protects everyone
• accurate records improve scientific reliability
• scientific conclusions must be supported by evidence

Scientific inquiry provides a reliable method for investigating questions about the natural world.

Looking Ahead

Next we will investigate cells, living organisms, biological organization, and the remarkable systems that make life possible.