Idea 4of 12Builds onWhere she isEvery metre counts
Start to finish
How far is she from where she began?
Today you'll discover
- a question that ignores the whole path
- how twelve metres of walking can end at nothing
- one arrow that answers it
LookRemember where she starts
She starts at the flag. Keep that place in mind.
Answer each question before pressing Next. Watch for the moment the legs disappear.
A walk drawn one leg at a time. First a flag on a ground line. Then a dashed warm arrow runs six metres east from the flag to a figure. Then a dashed cool arrow runs six metres back west to the flag, with a thin bracket above the figures spanning every metre walked, labelled twelve metres. Then the legs and clocks vanish and only two things remain: the bracket, distance walked twelve metres, and a small ring at the top where an arrow from start to finish would be, labelled zero. The last step shows the dog's run and asks the same question.
See the whole ideathe big idea and the key word, in one place
The big idea
Distance counts the trip. Displacement compares start and finish.
Compare themDistance asks about the path. Displacement asks only about the two ends, and ignores everything in between.
Key word
- displacement
- the straight arrow from where something started to where it finished; a number with a direction
Ready to use it?
- Say the displacement of a walk that turns around.