Hey,guys!I have a question about significant figures.I have chemistry 1 and physical science in this semester. They taught me significant figures in this week.My chemistry teacher taught me five rules to count the significant figures of a number.Here is the five rules:
Rule#1 all nonzero digits are signicant.
For example: 234 have 3 sigicant figures
Rule#2 zero in between significant figures are signicficant
for example: 1024 have 4 signicant figures
rule #3 zeros at the end and to the right of the demical are significant
for example 10.00 have 4 significant figures
rule #4 zeros at the end of to the left of the demical are not significant
for example : 900000 only have 1 significant figures , but 900000. have 6 significant figures
rules #5 zeros at the beigining of the number are not significant
for example 0.0009 have 1 significant figures
But my physical science teacher taught me a different method,he said 900000 have 6 signifcant figures.Because when try to mark off a zero at the end of 900000, the vaule have change to 90000,it is different to the origin number.same ,we can not mark other zeros, too.So my physical sicience teaher said 900000 have 6 significant figures.
Another example in my physical sicience class, 0.023. My physical science teacher said we can mark off the zero ,which is infront of the demical ,then he got .023,is same as 0.023. But we can not mark off the 0 after the demical。So he said 0.023 have 3 significant fiugures.
But if i use my rules, which i have learned in chemistry,then i have 2 significant figures for 0.023. According to rules number 5 "zeros ate the beigining of the number are not significat." 0.0 are not count as significant figures. So 0.023 have 2 siginificant is right in my chemistry class.
What do you think?Which method is right?
acctually， I believe the five rules are right. But are these five rules only apply in chemistry? (image from a college professor,s power point) http://faculty.atu.edu/abhuiyan/chem_2124.html (chapter 1)
By the way, thank you geno1314.
+118702 Neither method is completely correct. Your rules 3 and 4 are not always correct. Especially not rule four. (Rule 3 is probably ok)
For instance.
my bookcase is 900mm long. In this case one of the zeros is definitely significant. Maybe both.
so it depends on the exact situation as to whether zeros to the imediate left of the point are significant.
Your physical science teacher does not know what he is talking about. How rude am I.
I'd like to explain better but im on my phone and it makes everything harder.
+23254 The chemistry teacher gave you the correct rules.
Your physical science teacher gave you someincorrect information; go to your chemistry teacher and explain what the physical science teacher told you. Your chemistry teacher can go to the physical science teacher and correct that person's misconceptions.
Rule 4 is correct.
Rule 3: Zeros to the left of the non-existing decimal point are tricky -- if any of the zeros of 90000 (without a decimal point) are significant, they need to be indicated, usually by placing a bar over the last one (to the right) that is significant. If there is a decimal point at the end, such as 90000., then all those zeros are significant.
