Observation, explanation, and honest records

Where we are on the map

The map shows the reasoning order. Its numbers are worked examples unless the lesson explicitly identifies your own measurement. You are in the first of eleven blocks.

A question from daily life

You let go of a swing and it gradually stopped. You saw the stopping; the reason is still a proposal. Those are different statements.

Words and meanings

A pendulum is a weight hung from a string so it can swing from side to side. An observation reports what you saw or measured: ‘after ten swings the motion was smaller.’ An explanation proposes a cause: ‘air and the pivot resisted the motion.’ Data are recorded observations and numbers. A data source says who made a record, when, and how. If you did not count ten swings, do not add that number to make a sentence look scientific.

Predict before checking

Before watching again, predict whether the swing will travel less far from the middle after several trips. That distance from the middle to the farthest visible point is called its extent here; we will learn a precise measure later.

Do it and record it

Ask an adult to gently move an empty safe swing, or watch a short unedited clip. Record only what you actually see, such as ’each farthest position moved closer to the middle.’ If you cannot observe it, use the numbers below and label them ‘worked example’.

A worked example

Record A: ‘The pendulum completed 10 swings in 11.0 seconds’ is data if it was actually measured. Record B: ‘It slowed because of friction’ is an explanation to test separately. Record C: ‘Worked data: 11.0 seconds’ is an honest use of a supplied number.

A common mistake

Do not call an invented number your experimental result. Do not treat the first plausible explanation as proven. ‘I do not know yet’ is a valid scientific statement when followed by a plan to check.

A new situation

A phone became warm during a game. Name one observation and two possible causes that would need different checks. Do not dismantle or deliberately heat the phone.

Notebook entry and self-check

Make three notebook columns: ‘observed’, ‘I think’, and ‘how I would test’. Mark the source: your own observation or a worked example. Check that the first column does not claim an invisible cause.

Next lesson: Prediction and experiment: change one condition