Science is not just about remembering formulas, definitions, and diagrams. It is also about learning how to think carefully, question information, and separate evidence from belief.

Every day, students come across hundreds of statements—from textbooks and teachers to YouTube videos, social media posts, advertisements, and conversations with friends. Some statements are facts. Some are opinions. Others are assumptions that may sound true but have not actually been tested.

Learning to distinguish between fact, opinion, and assumption is therefore an important part of developing scientific thinking.

What Is a Fact?

A fact is a statement that can be supported or verified using reliable evidence.

For example:

• Water freezes at 0°C under standard atmospheric pressure.
• The Earth revolves around the Sun.
• Plants require light for photosynthesis.
• The human heart pumps blood through the circulatory system.

A scientific fact is not simply something that “sounds correct.” It should be supported by observations, measurements, experiments, or reliable scientific evidence.

Remember:

Fact → Evidence → Verification

If a statement can be independently checked using reliable evidence, it may be a fact.

What Is an Opinion?

An opinion is a personal belief, preference, or judgment.

For example:

• “Physics is the most interesting subject.”
• “Science experiments are more fun than reading textbooks.”
• “Mathematics is difficult.”
• “Space is the most fascinating topic in science.”

These statements cannot necessarily be proved right or wrong because they express someone’s personal viewpoint.

Two students can have completely different opinions about the same topic. That is perfectly normal.

Remember:

Opinion → Personal viewpoint

An opinion becomes different from a scientific conclusion because a scientific conclusion is based on evidence rather than personal preference.

What Is an Assumption?

An assumption is something we accept as true without having enough evidence to establish that it is true.

For example:

“The plant is growing slowly because it doesn’t get enough water.”

This might be correct—but unless we investigate the plant’s watering, sunlight, soil, temperature, and other conditions, we don’t actually know.

Another example:

“Rahul scored poorly in the test because he didn’t study.”

Maybe he did not study. But perhaps he studied and misunderstood the concepts, had difficulty interpreting the questions, or made calculation errors.

The statement is an assumption until there is evidence to support it.

Remember:

Assumption → Belief without sufficient evidence

The Science Thinking Challenge

Now let’s test your scientific thinking.

For each statement below, decide whether it is a:

F — Fact
O — Opinion
A — Assumption

Don’t look at the answers immediately!

Challenge 1: “The Sun is a star.”

Fact, opinion, or assumption?

Challenge 2: “Physics is the most difficult science subject.”

Fact, opinion, or assumption?

Challenge 3: “Plants kept in darkness will grow faster because they will search for sunlight.”

Fact, opinion, or assumption?

Challenge 4: “Iron is attracted to a magnet.”

Fact, opinion, or assumption?

Challenge 5: “Ananya is carrying a science book, so she must be preparing for an examination.”

Fact, opinion, or assumption?

Challenge 6: “Reading science books is more enjoyable than watching science videos.”

Fact, opinion, or assumption?

Challenge 7: “Objects fall toward the Earth because of gravity.”

Fact, opinion, or assumption?

Challenge 8: “This student got the highest marks because she is naturally intelligent.”

Fact, opinion, or assumption?

Challenge 9: “Water boils at a lower temperature at high altitudes than at sea level.”

Fact, opinion, or assumption?

Challenge 10: “Science experiments are the best way to learn science.”

Fact, opinion, or assumption?

Answers and Explanations

1. The Sun is a star. — FACT

The Sun is a star located at the centre of our solar system. This is supported by astronomical observations and scientific evidence.

2. Physics is the most difficult science subject. — OPINION

Difficulty depends on the individual student. There is no universal scientific measurement proving that physics is the “most difficult” science subject.

3. Plants kept in darkness will grow faster because they will search for sunlight. — ASSUMPTION

The statement proposes an explanation without sufficient evidence. Plant growth depends on several factors, including light, water, nutrients, temperature, and the type of plant.

4. Iron is attracted to a magnet. — FACT

Iron is a ferromagnetic material and can be strongly attracted to a magnet under ordinary conditions.

5. Ananya is carrying a science book, so she must be preparing for an examination. — ASSUMPTION

We have observed that she is carrying a science book. We have not established why she is carrying it. She could be studying, going to class, reading for fun, or helping someone else.

6. Reading science books is more enjoyable than watching science videos. — OPINION

Different students prefer different learning methods. This statement expresses a personal preference.

7. Objects fall toward the Earth because of gravity. — FACT

The gravitational interaction between Earth and objects near it causes objects to accelerate toward Earth.

8. This student got the highest marks because she is naturally intelligent. — ASSUMPTION

The marks are observable evidence. But the reason for the result cannot automatically be determined from the marks alone. Study habits, preparation, understanding, practice, test-taking strategy, and many other factors could contribute.

9. Water boils at a lower temperature at high altitudes than at sea level. — FACT

Boiling occurs when a liquid’s vapour pressure equals the surrounding pressure. Atmospheric pressure is generally lower at higher altitudes, so water can boil at a lower temperature.

10. Science experiments are the best way to learn science. — OPINION

Experiments are extremely useful for understanding scientific concepts, but different learning approaches can be useful for different concepts and learners. Calling one method “the best” is a judgment rather than a scientific fact.

Why Do Students Confuse Facts and Assumptions?

One reason is that assumptions often sound like facts.

Consider this statement:

“He failed the test because he didn’t study.”

It sounds convincing.

But what evidence do we have?

Maybe we know that the student did not study. Then the statement has some evidence behind it—but we still need to be careful before claiming that this was the reason for the result.

Scientific thinking teaches students to ask:

“How do we know?”

That simple question can change the way a student approaches information.

The “How Do You Know?” Test

Whenever you hear an important statement, ask these five questions:

1. What exactly is being claimed?

Identify the statement clearly.

2. What evidence supports it?

Look for observations, measurements, experiments, or reliable sources.

3. Can the claim be tested?

A scientific claim should generally be open to investigation.

4. Is there another possible explanation?

Don’t immediately accept the first explanation that comes to mind.

5. What information are we missing?

Recognising what we don’t know is an important scientific skill.

Try This With Everyday Information

The challenge doesn’t have to stop with science textbooks.

Take statements from everyday life.

For example:

“Students who study early in the morning always perform better.”

Ask:

• Is this a fact?
• What evidence supports it?
• Does “always” make the claim too strong?
• Do all students have the same sleep patterns?
• Could other factors influence performance?

This doesn’t mean the statement is necessarily false.

It means we should avoid accepting it without examining the evidence.

Why This Skill Matters Beyond Science

The ability to distinguish fact, opinion, and assumption is useful far beyond science examinations.

It can help students:

• Analyse information critically
• Read questions more carefully
• Evaluate claims
• Avoid jumping to conclusions
• Identify missing information
• Interpret experiments more accurately
• Make better decisions
• Become more independent learners
• Question information encountered online

In a world where students encounter information from countless sources every day, knowing something is not enough. Students also need to know how to evaluate what they are told.

From Memorising Answers to Thinking About Evidence

One of the most valuable habits a young learner can develop is to replace:

“Is this true?”

with:

“What evidence tells us that this is true?”

That small change encourages curiosity, skepticism, observation, and logical reasoning—the same habits that form the foundation of scientific thinking.

Science is not simply a collection of facts.

It is a way of asking questions, testing ideas, examining evidence, and changing our understanding when new evidence appears.

Final Takeaway

The next time you hear a scientific claim, don’t accept it automatically.

Pause and ask:

Is it a fact?
Is it an opinion?
Or is it an assumption?

And most importantly:

What is the evidence?

Developing this habit can help students become better science learners—and, more importantly, better thinkers.

Igniters Science Club, an initiative of Igniters for Tomorrow, encourages students to go beyond memorising science and develop curiosity, questioning, observation, and evidence-based thinking through meaningful learning experiences.