What is the scientific method? A simple answer
The scientific method is a way of finding out whether something is true by testing it and looking at the evidence, instead of just guessing. That is all it is. If you have ever wondered "which bubble mixture makes the biggest bubbles?" and then tried a few, you have already used it.
This guide is the easy version. It is written for children aged about 8 to 13, and for the parents and teachers who help them. There are no long words that we do not explain, and there are two real experiments you can do with things from the kitchen and garden. Older students preparing for exams will find more detail in our guide to how to use the scientific method in 6 steps.
Scientists are question detectives
Think of a detective. They do not accuse someone because of a hunch. They look for clues, test their ideas and change their mind if the clues say they were wrong. Scientists work the same way.
A scientist (and that includes you) does four big things:
- Asks a question that can be answered.
- Tests an idea with a fair experiment.
- Collects evidence by measuring or counting.
- Draws a conclusion that matches the evidence.
The best part is that a scientist is allowed to be wrong. When a prediction turns out wrong, you have still learnt something true. We will see this happen in the garden experiment.
The 6 easy steps, in kid language
People write the steps in slightly different ways. Here is a friendly version with six steps. Tap each card to flip it.
The picture above shows steps 2 and 3 from our scrapbook of the method. Notice the plant question: "Does the amount of sunlight affect how quickly a plant grows?" It is a good question because you can test it by growing plants and measuring them.
Is it always exactly six steps in order?
No. Real scientists jump back and forth. A surprising result might send you back to step 2 with a new question. A test that goes wrong might make you redo step 4. The steps are a map, not a rule book.
The idea is the same wherever you meet it. In England, the primary science curriculum (the set of things pupils are taught) calls this "working scientifically". It lists five kinds of enquiry that children should try:
- observing things over time (like watching a bean grow);
- looking for patterns;
- identifying, classifying and grouping things;
- comparative and fair testing, also called controlled investigations;
- researching using books and websites.
Fair testing is the one most people picture when they hear "experiment", and it is the main skill in this guide. Not every science question needs a fair test, though. If you are sorting leaves into groups or counting birds in the garden for a week, you are still a real scientist.
Why does the scientific method matter outside science lessons?
Because it helps you decide what to believe. Suppose a friend says "trainers with bright laces make you run faster." The scientific method gives you a way to check. You could time ten runs in each pair, keep the track, the runner and the weather the same, and compare. If the times are the same, the claim does not hold up.
Grown-ups use the same thinking when they test a new recipe, work out why a plant is dying, or decide if an advert is telling the truth. Some of this overlaps with how psychologists use the scientific method to study people, which is a good topic for much older students.
Before you start: a quick word on safety
The two experiments in this guide are gentle. They use water, paper and seeds. Even so, here are the ground rules we use on all home experiments:
- Tell an adult what you are doing, and ask for help with anything hot, sharp or electrical.
- Do not taste your experiment, and keep the materials away from small children and pets.
- Wash your hands after touching soil, seeds, compost or damp paper.
- Mop up spills straight away so nobody slips.
- Never mix cleaning products or other chemicals from around the house.
We repeat the key safety points next to each experiment. Now let us do some science.
Experiment 1 (kitchen): which paper towel soaks up the most water?
Our first simple science experiment for kids uses kitchen paper. You can do it in about twenty minutes, and it shows every step of the method. You will need two or three different kinds of paper towel (different brands, or kitchen roll and tissue), a plate, a dropper or a small spoon, a ruler, scissors, a jug of water, a pencil and a notebook.
Step 1: Notice
You spill some juice. One towel turns soggy and tears, while another wipes it up and stays strong. That is your puzzle. Do some towels really soak up more than others?
Step 2: Ask a testable question
Write your question so that it can be answered with a number:
Which paper towel soaks up the most drops of water?
Step 3: Predict (make your hypothesis)
Use the If… then… because… pattern. For example: "If I test a thick towel and a thin towel, then the thick towel will soak up more drops, because it has more paper to hold water." Your prediction might be right or wrong. Both outcomes are useful.
Step 4: Plan a fair test
A fair test is a test where only one thing changes. Everything else is kept the same, so you know what caused any difference. Scientists give these things names, and it helps to learn them early:
| Name | Kid-friendly meaning | In our experiment |
|---|---|---|
| Independent variable | The one thing you change | The type of paper towel |
| Dependent variable | The thing you measure | The number of drops soaked up |
| Control variables | Things you keep the same | Size of each piece, same plate, same dropper, same water, same waiting time |
Here is a simple way to remember it: change one, measure one, keep the rest the same.
Step 5: Do the test and measure
- Cut a square of each kind of towel, all the same size. Ten centimetres by ten centimetres is a good size. Measure with the ruler.
- Lay the first square flat on a clean plate.
- Add drops of water from the dropper, one at a time, in the middle of the square. Count each drop.
- Stop when the towel cannot soak up any more and a little puddle starts to form. Write down how many drops it took.
- Dry the plate, use a new square, and repeat for the next type of towel.
- Repeat the whole test three times for each towel, using a fresh square each time.
Make a table in your notebook before you begin, so that you can fill it in as you go. Use one row for each type of towel and columns for tries 1, 2 and 3.
Step 6: Work out the average and draw a conclusion
Now add up your three numbers for one towel and divide by three. That gives you the mean, which many people call the average. The range is the biggest number minus the smallest. A small range means your readings agreed well.
Below is a calculator you can try. The numbers in it are imaginary practice results, not a real brand test. Type in your own three readings to see your mean and range.
Suppose towel A gave 42, 45 and 40 drops, and towel B gave 30, 28 and 31 drops. Towel A has the higher mean, so in this imaginary test it soaked up more. Your conclusion could be: "Towel A soaked up more drops than towel B in my test, so my prediction was supported." Notice the careful words in my test. You only tested these towels, in this way.
The fill-in-the-blanks investigation planner
You can use this planner for any investigation, not just paper towels. Copy it into a notebook and fill in the gaps. Tick each box as you finish. (Your ticks are saved on this device.)
- My question: Does ______ change how much / how fast / how many ______?
- My prediction: If I ______, then ______, because ______.
- The one thing I will change: ______
- The one thing I will measure: ______ (units: ______)
- Things I will keep the same (at least three): ______, ______, ______
- Equipment I need: ______
- How many times I will repeat it: ______ (aim for 3)
- Safety check done with an adult: ______
- My table is drawn and ready: yes / no
- My conclusion starts with: "My results show that ______, so my prediction was ______."
- One thing I would improve next time: ______
Test the planner on someone else's idea too. Try it on "Does a sponge or a cloth hold more water?" and see whether you can fill in every blank.
Experiment 2 (garden): do seeds grow better in the light or in the dark?
This is a classic home plant experiment for kids, and it comes with a surprise. You need cress seeds (cheap from a garden centre or supermarket), kitchen paper or cotton wool, two shallow dishes or saucers, water, a ruler marked in millimetres, a cardboard box and a notebook. It takes about a week.
Notice and ask
You see a forgotten potato in a dark cupboard that has grown long, pale shoots. Why? Does light matter to growing plants? Your question: Do cress seeds grow taller in the light or in the dark?
Predict
Most people predict: "If I put cress in the dark, then it will not grow, because plants need light." Write your own prediction down before you start. That is what makes the result exciting.
Plan the fair test
| Type of variable | What it is here |
|---|---|
| Change (independent) | Light: one dish gets daylight, the other is covered |
| Measure (dependent) | Height of the seedlings in millimetres |
| Keep the same (control) | Number of seeds, type of seed, amount of water, type of paper, same dish size, same room |
Do the test
- Line two dishes with the same amount of damp kitchen paper.
- Sprinkle the same number of cress seeds on each. Twenty is plenty.
- Put both dishes side by side on a windowsill that is not in direct harsh sun. Cover one dish with the box so no light gets in. The air inside is enough for the seeds, and you will lift the box briefly each day.
- Each day, lift the box for a moment, add the same amount of water to both dishes, and keep the paper damp but not swimming.
- After three, five and seven days, measure five seedlings in each dish and record the heights.
Seeds need water, air and the right temperature to start growing, which is called germination. Some seeds also need light or darkness. Many common garden seeds do not need light to begin growing, so you may see them sprout in both dishes.
Record your results
Copy this table into your notebook and fill it in. The numbers below are blanks for you, not real results.
| Day | Light dish: height (mm) | Covered dish: height (mm) | What I saw (colour, shape, droopy?) |
|---|---|---|---|
| 3 | ____ | ____ | ____ |
| 5 | ____ | ____ | ____ |
| 7 | ____ | ____ | ____ |
Do not forget to write down what the seedlings look like, not just the height. A scientist's notes are called observations, and they are evidence too.
The surprise: what usually happens
Seedlings that grow without light usually become tall, thin and pale. Scientists call this etiolation. Their stems stretch long and weak, and they look yellowish-white instead of green. The seedling is stretching to look for light. Plants in the light stay shorter and sturdier, with green leaves.
So the dark dish may actually be taller after a few days, but the plants are unhealthy and will not last. That is a perfect example of why we do not stop at "which is taller?" It also shows why your prediction and your conclusion can disagree. If your prediction was "no growth in the dark", the evidence may say you were wrong. That is a good result, not a bad one.
Green plants use light to make their food, a process called photosynthesis. You can read more in our guide to photosynthesis. A seedling in the dark can live on the food stored in its seed for a while, but it cannot make more.
Draw your conclusion
A good conclusion has four parts, as the checklist above shows: what you found, the evidence, whether your hypothesis was supported, and anything that might have gone wrong. For example:
"The seedlings in the dark were taller but paler. My prediction that they would not grow was not supported. I measured five seedlings each time. Next time I would measure ten."
Safety for the garden experiment
- Do not eat the seeds or the seedlings from your experiment. They have been handled, and damp paper is a good home for germs.
- Wash your hands after handling seeds, damp paper or soil.
- Keep an eye out for mould on damp paper. If you see fuzzy grey or green patches, ask an adult to bin the dish, and do not sniff it.
- If you move the experiment outside, ask an adult before you handle tools, compost bags or garden chemicals.
Ready for the school lab one day? Our page on lab basics and simple experiments covers older-student safety rules, but for now these home rules are plenty.
10 easy investigation ideas with the variables filled in
Use the planner from Experiment 1 for each one. The table shows what to change, what to measure and what to keep the same.
| Question | Change this | Measure this | Keep the same |
|---|---|---|---|
| Which ball bounces highest? | Type of ball | Bounce height (cm) | Drop height, floor, same person measuring |
| Does sugar dissolve faster in warm or cold water? | Water temperature (adult handles any hot water) | Time to dissolve (seconds) | Amount of sugar, amount of water, stirring |
| Which paper plane flies furthest? | Wing shape | Distance (m) | Same paper, same thrower, same spot |
| Does a bigger parachute fall more slowly? | Size of parachute | Fall time (seconds) | Weight, drop height |
| Which material keeps a drink coldest? | Wrapping material | Temperature after 30 minutes | Starting temperature, cup size, time |
| Do bigger magnets lift more paperclips? | Magnet size | Number of paperclips | Clip type, same surface |
| Which kitchen surface is slipperiest for a toy car on a ramp? | Surface material | Distance rolled (cm) | Ramp height and angle, same car |
| Do softer pencils (like 4B) make darker marks than harder ones (like HB)? | Pencil grade (HB, 2B, 4B) | Darkness (compare with a shade chart) | Pressure, paper |
| Does the tea bag steep faster in hot or cold water? | Water temperature (adult for hot water) | Time until the colour is the same | Cup size, same bag |
| Does the length of a pendulum change its swing time? | String length | Time for 10 swings (seconds) | Weight on the end, size of swing |
For each one, ask yourself the same three questions: What am I changing? What am I measuring? What must stay the same?
Science words made simple: a glossary
Scientists use special words, but each one has a simple meaning. Keep this table next to your notebook.
| Word | What it means |
|---|---|
| Observation | Something you notice with your senses or a measurement. For example, "the seedling is pale". |
| Question | What you want to find out, written so it can be tested. |
| Hypothesis | A testable idea about what will happen and why. "If… then… because…" |
| Prediction | What you expect to see in your test. Often used together with hypothesis. |
| Variable | Anything that can change in an experiment. |
| Independent variable | The one thing you change on purpose. |
| Dependent variable | The thing you measure to see the effect. |
| Control variable | A thing you keep the same so the test is fair. |
| Fair test | A test where only one variable is changed. |
| Evidence | The results and observations you collect. |
| Data | Numbers or facts you have recorded. |
| Mean | The average: add the numbers, then divide by how many there are. |
| Range | The biggest value minus the smallest value. |
| Reliable | You get similar results when you repeat the test. |
| Conclusion | The answer to your question, based on your evidence. |
| Anomaly | A result that does not fit the pattern. Check it, do not just throw it away. |
Common misconceptions kids (and grown-ups) have
Tips for parents and teachers
- Let children predict first. Ask "what do you think will happen, and why?" before they start. Do not correct the prediction; let the evidence do that.
- Ask "how do you know?" Encourage the habit of pointing to evidence. Our article on why critical thinking matters for science students explains this habit in more detail.
- Keep the kit simple. Kitchen items are fine. You do not need a lab coat.
- Praise the plan. A neat table and a clear fair test deserve as much praise as a "right" answer.
- Use mistakes. Ask "what could we change to make it fairer next time?"
- Link to the curriculum. For primary pupils, asking questions, fair testing, recording in tables and bar charts, and drawing simple conclusions are all part of the national curriculum in England. For secondary pupils, the same ideas return with more detail.
- Move up gradually. When a child is ready for exam-style practicals, a good next step is our guide on how to start revising for GCSE science.
Test yourself with the scientific method quiz
Key points to remember
Frequently asked questions about the scientific method
What is the scientific method in simple words?
The scientific method is a way of finding answers by testing ideas. You ask a question, make a prediction, do a fair test, measure what happens and use your results to draw a conclusion. It helps people decide what is true using evidence rather than guesses.
What are the steps of the scientific method for kids?
A simple version has six steps: notice something, ask a question, make a prediction, test it fairly, measure and record the results, and draw a conclusion. Different books use slightly different lists, and real scientists often go back and repeat steps when they learn something new.
What is a hypothesis for kids?
A hypothesis is an idea you can test, with a reason attached. A good way to write one is "If I change this, then that will happen, because…". It is not just a wild guess. It is a prediction based on what you already know.
What is a fair test?
A fair test is an experiment where you change only one thing and keep everything else the same. That way, if you see a difference, you know your change caused it. Children first meet comparative and fair tests in primary science.
What are variables in an experiment?
Variables are things that can change in an experiment. The independent variable is the one you change on purpose. The dependent variable is the one you measure. Control variables are the things you keep the same so that the test is fair.
Why do scientists repeat experiments?
Repeating a test shows whether the results are reliable. One result could be a fluke caused by a small mistake. If you get similar numbers each time, you can trust the pattern more. Taking the mean of several readings also reduces the effect of any one odd result.
What are easy science experiments to do at home?
Try the paper towel absorbency test and the cress seeds in light and dark test in this guide. Other ideas are comparing bouncing balls, testing how fast sugar dissolves in warm and cold water, or timing paper planes. Always ask an adult first, and keep hot water and sharp tools adult-only.
Can an experiment be wrong?
A prediction can be wrong, but an experiment that is fair and careful is never a waste. It gives you real evidence. An experiment can be poorly designed, for example if two things change at once, and that is why we plan carefully and then think about how to improve.
What age is the scientific method taught?
Children start to use its ideas in primary school, by asking questions, making observations and doing simple fair tests. In England this is called working scientifically. In secondary school the same ideas become more detailed, with graphs, averages and evaluating errors.
Where can older students learn more?
Older students can read our longer guides on using the scientific method step by step with GCSE-style examples, and on how psychologists test ideas. Both go much further than this beginner guide and include more detail on analysing data and writing up investigations.
