Earth & Space
Carrying out the fair test: at least three sizes, same height, timed in parts of a second, repeated.
⏱ Whole lesson ≈ 44 min · pick a tier in the bar, or leave on "All"
Recap of last lesson: the plan & variables.
We change the ____ and measure the ____.
How could we make our results more reliable — that is, more likely to repeat?
Practise the stopwatch: start, stop, reset to zero.
Use at least three parachute sizes. Time in parts of a second (whole seconds are too rough). Drop from the same height every time.
Show me: start, stop, reset the stopwatch.
Why time in parts of a second rather than whole seconds?
Why repeat each size and take an average? What does that improve?
Teacher models a clean drop and how to record it, then watch the science.
Swap the clip: change the ID after /embed/ (now x6ovQErh4Mw).
Build the results table together and do one drop as a class.
Size (cm²) | Try 1 | Try 2 | Try 3 | Average time (s)
Play the animation. Bust: it's the wind slowing it, not air resistance.
From the same height, the big parachute falls more slowly — more air resistance.
Watch for: "it's the wind slowing it, not air resistance", and stopwatch slips (forgetting to reset).
Spot what would spoil the results.
On your own. Sort each action, then run and record at your tier.
Tap a card to sort it…
Sort the cards, then record your times in the table.
Sort them, then record three sizes with repeats and work out each average.
Sort them, then explain how repeating and averaging makes your results more reliable.
Answer at your tier, then hand it in.
How do you know your results are reliable? Give two reasons.