The Scientific Method
The Scientific Method
Navigate the knowledge tree: 🌿 Skills ➡ Life Processes
Go to the Lesson Outline for Observations
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Navigate the knowledge tree: 🌿 Skills ➡ Life Processes
Go to the Lesson Outline for Observations
Learning Intentions
By the end of this topic, you should be able to:Learning Intentions
Describe the steps of the scientific method and explain why science relies on evidence rather than opinion.
Distinguish between observations, inferences, hypotheses, predictions, and conclusions using real-world examples.
Glossary
Key terms and definitions.Glossary
hypothesis: A testable statement that tries to explain an observation. It leads to predictions that can be checked with evidence.
inference: A logical idea or explanation based on observations — an educated guess about what the observations mean.
observation: Information gathered using the five senses or scientific tools such as microscopes and thermometers. Observations describe what is actually happening.
prediction: A statement about what you expect to happen in the future if the hypothesis is correct.
reliability: When an investigation produces similar results every time it is repeated in the same way.
scientific method: A logical process that uses observations, hypotheses, predictions, and experiments to build reliable scientific knowledge.
scientific theory: A well-supported explanation of why something happens in nature. It is based on strong evidence, widely accepted by scientists, and can be changed if new evidence is discovered.
What is the scientific method?
What is the scientific method?
Scientific knowledge doesn’t just appear — it is built through a special process called the scientific method. This is a systematic way that scientists use to turn ideas and questions into reliable explanations about the world.
The scientific method:
Uses observations, measurements, and experiments
Helps develop hypotheses (possible explanations)
Tests these hypotheses to see if they are supported by evidence
Leads to explanations that become theories when they repeatedly work
A key feature of the scientific method is that scientific knowledge can change. If new evidence shows that an explanation is incorrect, scientists update or replace their ideas. This means science is always improving.
Why is the scientific method important?
Why is the scientific method important?
The scientific method is important because it allows scientists to collect, record and analyse data, identify patterns or trends and reach reliable conclusions. It helps us learn how and why something happens and ensures that scientific explanations are based on evidence, not guesswork.Â
The scientific method separates facts from opinions and helps scientists solve real-world problems, such as developing new medicines, vaccines and understanding climate change. It also leads to exciting new discoveries, sometimes by surprise, and ensures that scientific knowledge is trustworthy, testable and based on evidence rather than guesswork.
Example:
Dr Edward Jenner observed that milkmaids who had cowpox did not get smallpox. This observation led to a hypothesis, experiments, and eventually the first vaccine, helping to eradicate a deadly disease.
What are the general steps in the scientific method process?
What are the general steps in the scientific method process?
I would like to preface this section with a note from the Science Learning Hub:Â
There is no one single method or pattern that all scientists follow. Scientists can make observations, ask questions, gather data, interpret data, build on the work of other scientists, use models, carry out experiments – and they will carry out such processes in many different ways.
For the purpose of introducing a process of working in a scientific manner, I will go over the general steps from observation to testing.
Step 1: Observing the world
Step 1: Observing the world
The scientific method begins with careful observations of the world around us. Observations involve using your five senses — sight, hearing, touch, taste, and smell — to gather information. Tools like microscopes or telescopes extend our senses and allow us to observe things that are too small, too far away, or too hidden to see directly.
Observations are an important starting point for scientific investigations because they raise new questions like:Â
Why did this happen?Â
What caused it?
Step 2: Making inferences
Step 2: Making inferences
After making observations, scientists try to explain what they have observed by making an inference. An inference is a logical idea about what the observation might mean. (So, observations = what you see, hear, smell, taste, or feel; inferences = what you think the observation means).
Here are some inferences from the example observations in Step 1: Observations.Â
Observation: The lemon is sour.
Inference: The lemon is acidic.Observation: Three chicks are chirping.
Inference: One of the parents are nearby with food.Observation: The rubbish is smelly.
Inference: There is rotten food inside the plastic bag.Observation: Measles is becoming more common.
Inference: Less children are receiving the measles vaccine.Observation: There are more hurricanes now than 10 years ago.
Inference: The ocean is warmer now than 10 years ago.Observation: There are fewer monarch butterflies around.
Inference: There are fewer habitats for monarch butterflies.
Observations are real and can be confirmed, but inferences are educated guesses that need further testing. Many inferences can be made from the same observation — but only some will be correct. That’s why scientists test them. It’s important not to confuse inferences with facts.Â
For example:
Observation: A dog is barking (fact)
Inference 1: It has found a rabbit (explanation, can be wrong)
Inference 2: It heard a stranger (explanation, can be wrong)
Step 3: Creating a hypothesis
Step 3: Creating a hypothesis
Once a scientist has made enough observations, they form a hypothesis. A hypothesis is a more formal type of inference — a testable statement that tries to explain an observation. A hypothesis must be based on evidence, be written as something that can be tested and lead to clear predictions.
Sometimes, scientists write hypotheses in a way that allows for statistical testing. This involves creating a null hypothesis, which is a statement saying that nothing will change or that one factor does not affect another.Â
The null hypothesis is tested to see if it can be rejected. If it is rejected with strong evidence, the original explanation — known as the alternative hypothesis — is supported.Â
This method helps prevent scientists from making assumptions without proof.
Step 4: Making predictions
Step 4: Making predictions
From the hypothesis, scientists make predictions about what they expect to happen if your hypothesis is correct. It describes a future observation, and helps scientists know exactly what they are looking for.Â
Predictions should be based on what is already known and what has been observed.
For example: If light colour does NOT plant growth, then plants grown under different colours of light will show no differences in growth.
Step 5: Testing the hypothesis
Step 5: Testing the hypothesis
To find out whether a hypothesis is correct, scientists carry out experiments or further observations to see if their predictions come true. This testing happens through:
Laboratory experiments or field investigations
More observations
Measuring and recording results
Experiments must be fair and repeatable so that other people can test the idea in the same way and get the same results. Anyone who repeats the same method should get similar results — this is called reliability. This keeps science honest and fact-based.
If the results support the prediction → the hypothesis is supported (not proven forever)
If results do not support the prediction → the hypothesis must be changed or rejected
If the hypothesis successfully predicts what will happen again and again, it becomes more likely to be true.Â
How does a hypothesis become a theory?
How does a hypothesis become a theory?
Over time, if a hypothesis is tested many times and continues to be supported by strong evidence, it may become a scientific theory. A scientific theory is an explanation of why something happens, that is based on unrefuted evidence and is widely accepted by the scientific community. Scientific theories are able to predict what will happen.
However, theories are not permanent. They can be changed or replaced if new evidence or better explanations are discovered. This is one of the most important features of science — scientific knowledge can grow and improve as we learn more.
More on The Scientific Method
📕 article 📸 image 🎮 interactive 🎦 videoMore on The Scientific Method
Glossary
Key terms and definitions.Glossary
hypothesis: A testable statement that tries to explain an observation. It leads to predictions that can be checked with evidence.
inference: A logical idea or explanation based on observations — an educated guess about what the observations mean.
observation: Information gathered using the five senses or scientific tools such as microscopes and thermometers. Observations describe what is actually happening.
prediction: A statement about what you expect to happen in the future if the hypothesis is correct.
reliability: When an investigation produces similar results every time it is repeated in the same way.
scientific method: A logical process that uses observations, hypotheses, predictions, and experiments to build reliable scientific knowledge.
scientific theory: A well-supported explanation of why something happens in nature. It is based on strong evidence, widely accepted by scientists, and can be changed if new evidence is discovered.
Practice Tasks for Different Thinking Skills
Practice Tasks for Different Thinking Skills
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