Fair Testing: Think Like a Scientist
FoundationScience grows from systematic observation, testing and analysis; a fair test changes only one condition, and new evidence updates knowledge.
- Scientific knowledge comes from systematic observation, testing and analysis.
- Science needs imagination and creativity too.
- A fair test changes only one condition and keeps the rest the same.
文體小知識：記敘文跟著實驗走。這一篇由紙飛機實驗的故事，學會公平測試和科學思考的規則。
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1Who says science belongs only in laboratories? What scientists do is very like the small experiments we try every day: watch carefully, ask a question, make a guess, then design a test to check it, analyse the results and reach a conclusion. This organised way of working is the heart of the scientific method.
2Scientists need imagination and creativity too. Newton imagined a stone thrown from a mountaintop and the Moon pulled by the same force, and reasoned out gravity; Mendeleev used the pattern of the periodic table to predict elements no one had found yet. Posing new questions and designing clever tests all take thinking. Observations stay objective while ideas can be bold — that is what makes science so fascinating.
3To be believed, test; to test well, be fair. The rule of a fair test is simple: change only one thing you are comparing each time and keep everything else the same. To compare how far two paper planes fly, throw from the same spot with the same strength and let only the wing design differ — then the result can be trusted.
4Scientific knowledge is not fixed. Long ago many people believed the Earth was a flat sheet — the flat-Earth idea. Later, sailors on long voyages noticed a ship's mast appearing before its hull, and Magellan's fleet sailed all the way around the world and returned to its starting point. More and more evidence showed the Earth is a sphere, and the spherical-Earth idea replaced the flat-Earth idea. Knowledge updates when new evidence appears.
5Next time you run a small experiment, remember three things: change only one thing at a time, record results honestly, and welcome new evidence. Think like a scientist — observe more, ask more, test more — and you too can find the hidden patterns of nature around you and become a little scientist.
1Summary 重點摘要
Science grows from systematic observation, testing and analysis; a fair test changes only one condition, and new evidence updates knowledge.
2Vocabulary cards Vocabulary
Looking carefully and recording things with our senses in an organised way.
A guess about the result, based on observation and experience.
A test in which only one condition changes while all others stay the same.
A condition that can change in an experiment; a fair test changes only one each time.
Observations and data that support or overturn a conclusion.
The answer reached after analysing the evidence.
Writing down or drawing observations and data truthfully.
The ability to form new ideas in the mind; scientists need it too.
The old idea that the Earth is a flat sheet.
The evidence-based understanding that the Earth is a sphere.
3Step by step Steps
- Step 1: Ask questions like a scientistScientific inquiry begins with observation and questions. Notice things around you and ask a testable question: Which paper plane flies farther? Do plants grow faster in shade or in sun? A good question is specific and measurable — not 'how can a paper plane be good' but 'which flies farther, a wide-winged or a narrow-winged plane?' Write the question in your inquiry notebook, then note the answer you expect; this guess is your prediction, and the test will check it.
- Step 2: Design a fair testThe most important rule of a fair test: change only the one condition you are comparing and keep all others the same. To compare two paper planes, only the design may differ; the throwing strength, direction, place and height must be the same, and so must the paper's material and size. If one plane is thrown hard and the other let go gently, we can never tell whether the difference came from design or from strength. The changed condition is the variable; the unchanged ones are controlled conditions — list them before you start.
- Step 3: Record data honestlyDuring the test, watch carefully and record results honestly. Use a table: fly each plane three times, measure and note each distance, then work out the average. Never record only the best throw because you want to win, and never change numbers afterwards. Data is evidence, and evidence must be true for conclusions to be trusted. Photos, drawings and measurements are all good records — if you forget, the notebook retells the whole test.
- Step 4: Analyse results and concludeAfter testing, put the data side by side: which plane flew farther on average? Is the gap clear? Write a conclusion supported by evidence, such as 'the narrow-winged plane flew two metres farther on average'. Never judge by feelings; conclusions must rest on data. Also ask: did the result match your prediction? If not, why? Being wrong is fine — scientists revise their ideas every day. What matters is learning something new from the data.
- Step 5: New evidence updates knowledgeScientific knowledge is never final; when new evidence appears, conclusions are corrected. The best example is the shape of the Earth. In ancient times many believed the flat-Earth idea, picturing land as a flat sheet. Later sailors noticed a ship's mast appearing before its hull, and Magellan's fleet sailed around the world and returned to its starting point. Evidence kept piling up for a spherical Earth, and people updated their understanding. Today we know the Earth is a ball — knowledge built bit by bit from evidence. Daring to correct mistakes is the scientific spirit.
- Step 6: Imagination drives scienceScience needs not only systematic observation and analysis but also imagination and creativity. Newton imagined a stone thrown from a high mountain and the Moon obeying the same pull, and reasoned out gravity; even designing a fair test takes clever thinking. Be bold in guesses and careful in proof: let imagination suggest interesting predictions first, then check them with fair tests and true data. Notice the questions hiding in daily life and dare to try — you can think like a scientist too.
5Worked example Example
Ming and Wah test which paper plane flies farther. Ming uses an orange narrow-winged plane and hurls it down from steps; Wah uses a blue wide-winged plane and releases it gently on flat ground. The blue plane flies shorter, and Wah says narrow wings fly farther. Is this test fair? What is unfair? How can it be fixed?
- The test changed two things at once: the plane design (narrow versus wide wings) and the throw (a hard hurl versus a gentle release).
- The two stood at different heights; throwing down from steps gives an advantage, so the results cannot compare fairly.
- A fair test should keep plane design as the only variable; throwing strength, height and place must be the same.
- The fix: one thrower stands on one line and throws both planes with the same strength, three tries each, then compare averages.
- Answer: The test was unfair: it changed design, strength and height at once, so no one can tell what caused the distance difference. The fair way is to keep design as the only variable — same thrower, same line, same strength, three tries each and then average — only then are the results trustworthy.
6Common mistakes Mistakes
7Quick check Quick check
Q1How many conditions may a fair test change each time?
Q2What do we call the observations and data that support a conclusion?
Q3What was the old idea that the Earth is flat called?
Q4What keeps updating scientific knowledge?
Q5When testing paper planes, how should the throwing strength be?
8Recap Recap
- Scientific knowledge comes from systematic observation, testing and analysis.
- Science needs imagination and creativity too.
- A fair test changes only one condition and keeps the rest the same.
- Record honestly and test several times for reliable results.
- When new evidence appears, knowledge updates — the spherical Earth replaced the flat-Earth idea.