the reading of an apparatus can read up to an accuracy of 0.01cm3...if it reading is 39.50cm3 can i write it as 39.5cm3....
my teacher say that it wrong...but i dont argree with it...
can anyone tell me the truth and give me the prove(to get the best answer)...tell me what is ur prove lor...
2007-06-11 21:44:11 · 5 answers · asked by red devil 4 in Science & Mathematics ➔ Chemistry
Your answer is acceptable only in that the value is correct. If you are requested to provide a value to a certain decimal then that is what you do. When you are the master of the ship then you may do as you want but your instructor wants a specific and they are Cap'n. Keep in mind what will happen with your answer. Is it just an answer, an answer TO A CERTAIN POINT, or will it be used for further calculation where a level of accuracy will be needed beyond what you provide. Science requires a high degree of accuracy well beyond what you are seeing here, esp. higher math and massively large or infinitesimal numbers.
But, your answer is as correct as your teacher, the point is also to follow direction.
2007-06-11 21:54:51 · answer #1 · answered by mike453683 5 · 1⤊ 1⤋
Hi!I have the same problem with you.But, i had found out the reason.
Significant figure is extremely important in chemistry and physics. This's because when the 0 is missing that's mean your measurement can has error form -0.1to -0.1. This will make your measurement not so 'sensitive'. Since your apparatus can read up to 0.01cm3, you should include the 0, which make it to become 4 significant figure.
2007-06-12 04:51:47 · answer #2 · answered by Wonder why 2 · 0⤊ 0⤋
it is wrong as far as accuracy goes.
although mathematically u r right, 39.50 is indeed, as a value 39.5, the information provided by saying 39.50 is lost.
the big idea is to learn that all measurements have an error in them. they are just trying to teach you to be able to evaluate this error.
and by saying 39.5 the actual value might just as well have been 39.46 or 39.54 (quite a difference between $39.46 million and $39.54 million, wouldn´t you say).
that´s why it is important to use all the accuracy a method or measurement can give u. so u know what the potential error might be.
2007-06-12 05:02:27 · answer #3 · answered by chem_freak 5 · 1⤊ 0⤋
It angered me too for the longest time. They call it Significant Figures.(dunt dunt du) A chemistry teacher finally explained it to me.
39.5 and 39.50 are obviously the same, BUT
The zero on the end indicates that you are more certain, more exact in your measurements.
However, It becomes horribly irrational to use this method on everyday numbers like:
2 + 9 = 10
233 + 1 =200
http://en.wikipedia.org/wiki/Significant_figures
39.50cm3 is correct, but keep challenging that teacher...
2007-06-12 05:04:47 · answer #4 · answered by ericnutsch 5 · 1⤊ 0⤋
39.45 < 39.5 < 39.55
39.495 < 39.50 < 39.505
2007-06-12 05:00:06 · answer #5 · answered by Helmut 7 · 1⤊ 0⤋