A child watches a puri puff, wonders why, then stops. Why is the investigation incomplete?

The question remains untested. The child must plan a test and use its results to answer the question.

Can a careful kitchen test count as an experiment?

Yes. Experiments can use ordinary household objects.

You choose the oil temperature, then measure puffing time. Which is the result?

Puffing time. The temperature is set beforehand; puffing time is measured during the test.

You change thickness and temperature together. Which caused the difference in puffing?

We cannot tell. Either change could affect puffing.

A child leaves splattering out because only puffing time was planned. Why record splattering too?

Unplanned observations can provide clues. Useful evidence can come from more than the measurement you planned.

Do all microorganisms in our bodies cause infections?

No. Some help digestion instead of causing infections.

An iron warms and a motor turns. Which effect of current makes the motor turn?

The magnetic effect. Heating warms things; the magnetic effect produces the motor’s turning.

A child predicts folded paper falls faster. What must happen before accepting that prediction?

Test it and observe. A prediction suggests a possibility; observations provide evidence to judge it.

Teach Exploring the Investigative World of Science in eight steps.

For each idea: show it, ask before you tell, then say one line.

Gather a coin, spoon, steel tumbler, water, ball, book, ruler, measuring tape, paper, rice, pencil, clear lidded container and curd.

Common misconceptions & worked visual for this chapter · 15 practice questions with answers

Why it matters

Puris puff in kitchens, where careful tests can explore everyday puzzles.
An electric iron warms because current has a heating effect.
Some tiny organisms in our bodies help us digest food.

What to teach

How to teach it

Plan and carry out an investigation

One hand holds a coin upright on a tabletop before spinning.

1. Investigation

Ask a focused question, test it, and learn from observations.

Show: Set a coin upright between your fingers. After predicting, spin it and watch.
Ask: Will it remain upright when the spinning ends?
Say: Plan a test for your question, then use the result to judge your prediction.
Used in: Tests of puri puffing help explore an everyday puzzle.

If your child says…“Watching carefully is the whole investigation.”

Ask: What test could answer the question you asked?
What’s true: An investigation also needs a planned test and an explanation of what the result means.

Empty steel tumbler beside a spoon and water jug.

2. Science is everywhere

Everyday objects can help us test scientific questions.

Show: Set out an empty steel tumbler, spoon and water. After predicting, compare gentle taps before and after filling.
Ask: Will adding water change the sound?
Say: A careful kitchen test counts as science.
Used in: Kitchen experiments let people investigate familiar things with equipment they already have.

If your child says…“Real experiments need a laboratory.”

Ask: What could a laboratory add to this particular comparison?
What’s true: The care taken with a test matters, wherever it happens.

A hand holds a ball on a ruler ramp, with measuring tape beyond it.

3. What we can change, observe or measure

We choose test conditions and record what happens.

Show: Prop a ruler on a book. After predicting, release the same ball from different points, without pushing. Keep the ramp unchanged. Measure from its bottom to each stopping place with a measuring tape.
Ask: Will changing the release point change how far the ball travels?
Say: You choose the release point; the distance travelled is a result.
Used in: Choosing dough thickness lets a puri experiment test its effect.

If your child says…“How far it rolls is what I control.”

Ask: Which can you set before letting go?
What’s true: You measure the travel distance after releasing the ball.

One hand holds flat and crumpled paper at equal heights before release.

4. Changing only one thing at a time

Change the tested condition while keeping the others steady.

Show: Prepare matching paper sheets, one flat and one crumpled. After predicting, drop them from equal heights.
Ask: Will changing the paper’s shape change how it falls?
Say: Keep the release height equal so the comparison tests shape.
Used in: Keeping dough thickness steady helps a puri test show what changing oil temperature does.

If your child says…“Changing shape and height together saves time.”

Ask: How would you tell whether shape or height caused the difference?
What’s true: Changing both makes the cause of a difference unclear.

Closed container of dry rice beside blank paper and a pencil.

5. Keeping notes

Record expected and unexpected observations, then ask what to test next.

Show: Close some rice inside a clear container. After predicting, shake gently and write what you notice.
Ask: What might you notice besides what you can see?
Say: Record unexpected observations too.
Used in: Notes about splattering can give clues beyond a puri’s puffing time.

If your child says…“I only record the result I planned to measure.”

Ask: What useful clue might your notes leave out?
What’s true: An unplanned observation can also provide evidence.

Explore this year’s science

A small steel bowl of plain homemade curd on a tabletop.

6. Tiny organisms

Some cause infections; others help digestion or medicine production.

Show: Set out a bowl of curd prepared for a meal. Recall that it began as milk.
Ask: Would milk turn into curd if no helpful bacteria were present?
Say: Helpful bacteria turn milk into curd. We cannot see individual bacteria here with our eyes alone.
Used in: Some microorganisms help us digest food.

If your child says…“Every tiny organism causes disease.”

Ask: Would an organism helping digestion fit your claim?
What’s true: Some cause infections, while others help us.

Diagram linking current to an iron’s heating element and a fan’s turning motor.

7. Heating and magnetic effects of electric current

Current can warm appliances and make motors turn.

Show: Look at the diagram. Follow how current heats the element, which warms the base. Then follow how magnetic forces turn the motor’s shaft.
Ask: What will happen to the iron’s base and the fan blades when current flows?
Say: Current heats the iron’s element, warming its base. Magnetic forces turn the fan’s motor.
Used in: Electric motors use the magnetic effect to run machines.

If your child says…“Magnetism is what heats the iron.”

Ask: Which part does the diagram connect to the iron’s hot base?
What’s true: The iron uses current’s heating effect.

Connect imagination with evidence

Diagram connecting knowledge, questions, predictions, observations and revised ideas with return arrows.

8. Roots and kites

Build on knowledge, imagine possibilities, and check them through observation.

Show: Look at the diagram. Follow knowledge through questions and predictions to observations, then follow the return arrows.
Ask: If observations disagree with a prediction, what do you think will happen to the idea?
Say: Follow the return arrows to see how observations help us rethink ideas.
Used in: Observations of the Moon and Sun helped people develop early calendars.

If your child says…“If I imagine it clearly, I know it works.”

Ask: Which arrow shows observations leading to a new question?
What’s true: An imagined improvement still needs testing.

A real problem

An investigation connected mosquitoes with malaria.

In 1897, Ronald Ross established a link between mosquitoes and malaria.

He dissected a mosquito that had fed on a malaria patient’s blood and found the parasite.

Later, he advised and helped malaria-prevention efforts in several countries.

Science Museum Group LSHTM

A mosquito rests on mosquito-net fabric.

Concept Lab · Common misconception

The tempting mistake in Exploring the Investigative World of Science

Open standalone misconception page →

Does a difference in one trial establish a reliable effect?

Wrong

Setup B always evaporates more water because it lost 5 mL while setup A lost 4 mL in the first trial.

Why it feels right. I treat one pair of measurements as typical.

Right

Repeat each trial to see whether a difference holds up against ordinary variation.

Worked example

Both setups have two readings of 4 mL and one of 5 mL.

Repeat both setups under the same conditions.
A loses 4, 5 and 4 mL.
B loses 5, 4 and 4 mL.
The averages are equal, so these trials do not support the claim that B evaporates more.

Ask your child eight quick questions.

One per step. The answer and the reason are given.

A child watches a puri puff, wonders why, then stops. Why is the investigation incomplete?

The question remains untested. The child must plan a test and use its results to answer the question.
Can a careful kitchen test count as an experiment?

Yes. Experiments can use ordinary household objects.
You choose the oil temperature, then measure puffing time. Which is the result?

Puffing time. The temperature is set beforehand; puffing time is measured during the test.
You change thickness and temperature together. Which caused the difference in puffing?

We cannot tell. Either change could affect puffing.
A child leaves splattering out because only puffing time was planned. Why record splattering too?

Unplanned observations can provide clues. Useful evidence can come from more than the measurement you planned.
Do all microorganisms in our bodies cause infections?

No. Some help digestion instead of causing infections.
An iron warms and a motor turns. Which effect of current makes the motor turn?

The magnetic effect. Heating warms things; the magnetic effect produces the motor’s turning.
A child predicts folded paper falls faster. What must happen before accepting that prediction?

Test it and observe. A prediction suggests a possibility; observations provide evidence to judge it.

15 more questions with answers

Teach Exploring the Investigative World of Science in eight steps.

Why it matters