Observation and experiment
Answers are for parents and teachers.
1
At home drop a sheet of paper and a ball crumpled from it from the same height (no higher than 1.5 m). What did you observe and what is your conclusion?
The ball lands first; the reason is that air resistance acts more strongly on the flat sheet.
2
For the question “does cold water freeze faster than hot water?” write a hypothesis and a plan for testing it.
Sample: Hypothesis — cold water freezes faster. Plan: put equal volumes of cold and hot water in identical containers in the freezer and check every 10 minutes.
3
Which instrument measures which quantity? Match: stopwatch, balance, thermometer, tape measure.
Stopwatch — time; balance — mass; thermometer — temperature; tape measure — length.
4
Count how many times your heart beats in 1 minute at rest. Count again 10 minutes later. Are the results the same?
The answer depends on your measurements; results are usually close but may differ — that is why measurements are repeated.
5
Aristotle said a heavier body falls faster. Was this a hypothesis or a law? Why?
It was a hypothesis: when tested in experiments (with negligible air resistance) it turned out to be wrong.