Idea 3of 6Builds onA question that can lose
Match the instrument
Which tool can see what you are measuring?
Today you'll discover
- why a stopwatch fails on a half-second fall
- what an instrument's smallest step must be
- the word for that smallest step
Think firstA ball falls for about half a second
Your reaction time is 0.2 s. The fall lasts 0.5 s. Which should time it?
Decide first, then press Next. The plan box is where the tool is chosen.
The inquiry ring. After a prediction, the plan box and then the collect-data box are named, with the camera's frame time explained. The last step asks which thermometer could see a small rise in temperature.
See the whole ideathe big idea and the key word, in one place
The big idea
Choose a tool whose smallest step is finer than the event.
For exampleTwenty hand-timed drops average out some of the reaction time, but not the lean. One filmed drop counted frame by frame beats them all.
Key word
- resolution
- the smallest change an instrument can tell apart: one frame, one marked division, one digit
Ready to use it?
- Pick the instrument whose resolution fits a measurement.