- #1
tyneoh
- 24
- 0
Greetings fellow members, I have some queries on a laughably rudimental topic regarding measurements.
Say you have a metre rule with sensitivity of 0.1cm, and you are measuring a wire which stretches from the 0.0cm starting point to the middle point between 7.3 cm and 7.4cm. My confusion arises here, do you measure the wire as 7.35cm or round it up to 7.4cm?
For me I would normally choose 7.35 cm but after learning about uncertainty and sensitivity, I am starting to doubt my original comprehension about measurements. When you measure it as 7.35cm, are you exceeding the sensitivity(0.1 cm) of the metre rule thereby "creating" an arbitrary reading? My teacher said that when you round it to 7.4cm, your reading includes 7.35 cm as the metre rule has an absolute uncertainty of 0.05cm, thus your reading would be (7.40+/-0.05)cm, which includes the 7.35cm.
To round up my question(no pun intended), when you measure an object do you measure it to the sensitivity or the uncertainty of the measuring equipment, 7.35cm or (7.40+/-0.05)cm?
Say you have a metre rule with sensitivity of 0.1cm, and you are measuring a wire which stretches from the 0.0cm starting point to the middle point between 7.3 cm and 7.4cm. My confusion arises here, do you measure the wire as 7.35cm or round it up to 7.4cm?
For me I would normally choose 7.35 cm but after learning about uncertainty and sensitivity, I am starting to doubt my original comprehension about measurements. When you measure it as 7.35cm, are you exceeding the sensitivity(0.1 cm) of the metre rule thereby "creating" an arbitrary reading? My teacher said that when you round it to 7.4cm, your reading includes 7.35 cm as the metre rule has an absolute uncertainty of 0.05cm, thus your reading would be (7.40+/-0.05)cm, which includes the 7.35cm.
To round up my question(no pun intended), when you measure an object do you measure it to the sensitivity or the uncertainty of the measuring equipment, 7.35cm or (7.40+/-0.05)cm?