Sig figs in calculations. (1 Viewer)

[Somehumanguy]

I’m a student sitting in the 2024 hsc cohort, im doing physics+chem, a question I had for a while is why is there so much concern in chemistry when it comes to maintaining the correct number of sig figs in your final answer while doing a calculation while in physics, the marking criteria won’t screw you over if you go a little over when it comes to significant figures.

 

[carrotsss]

iirc there’s usually one question in the hsc where they do mark for significant figures, and there’s no point giving up that mark for no reason

 

[wizzkids]

You're right. There is a difference in the way marking criteria are applied in these two subjects.
I think there is a cultural difference, as in scientific cultural difference.
Analytical Chemists value accuracy, validity and not over-stating the precision in a measurement or a calculation. When they write down the chemical composition of food, water or pharmaceuticals they know their job could be on the line if they get it wrong, or a product could be recalled from the market. Hence they frown at answers that infringe on these three criteria, especially students who naively over-state the precision (number of sig figs) in their answers.
Physicists value laws, mathematical formulae and critical reasoning and they are not as hung up about number of sig figs in an answer. They know their job won't be on the line if they over-state the precision of a the mass of a packet of Corn Flakes to more sig figs than is really justified.
That's my theory.

 

[Susu123]

I’m a student sitting in the 2024 hsc cohort, im doing physics+chem, a question I had for a while is why is there so much concern in chemistry when it comes to maintaining the correct number of sig figs in your final answer while doing a calculation while in physics, the marking criteria won’t screw you over if you go a little over when it comes to significant figures.

just write ur answers in the lowest number of sig figs given in the questions, works almost everytime

 

[t234]

just write ur answers in the lowest number of sig figs given in the questions, works almost everytime

so if the question has values to 3 sig fig and your answer is 2134, you'd round down to 2130? right?

 

[carrotsss]

so if the question has values to 3 sig fig and your answer is 2134, you'd round down to 2130? right?

yeah

if that feels silly just write it as 2.13* 10^3

 

[Susu123]

yeah

if that feels silly just write it as 2.13* 10^3

yeah most ppl i know tend to write scientific notation