Could You Pass 8th Grade Science?

[Angelspit]

Barely passed at 61% (thanks to a series of last-minute correct answers).

Were we really thought that kind of stuff in eight grade?

[Metathron]

See, all the brilliant minds barely pass, while the mundanes prosper.

[Veldrynus]

See, all the brilliant minds barely pass, while the mundanes prosper.

Yeah, damn C.!

[ThunderTitan]

Were we really thought that kind of stuff in eight grade?

I'm pretty sure i learned most of that before the 8th grade... as i recall in biology we where at human bodies (muscles, bones etc) and in geography we where learning where the toothpick factories where...

[asandir]

See, all the brilliant minds barely pass, while the mundanes prosper.

hehehe

[Banedon]

Well of course, I'd be embarassed if I scored any less than 95, really. Just my ultra-high standards speaking though

There're some questions I've never studied before (the Igneous Rock question especially) but with some intelligent guesses I got an 'A'. Sad no 'A+' though

[Thelonious]

I got a score of 85% Suppose that sould be better since I'm still at school, though I didn't really understand every word...



Edit:
Naw, it seems I'm just stupid...

[asandir]

not at all, that's a decent grade

the igneous rock one was easy (especially if you happened to study some geology at Uni )

[Thelonious]

Yeah, but I think I should've done better for an 18 year old who studies chemistry...

[winterfate]

@Thelonious: Well, I have a low B in General Chemistry...

And I still have 3 Chem classes left!

General Chemistry II
Organic Chemistry I
Organic Chemistry II



P.S: I didn't know you're younger than me.

[Banedon]

Asking this question here instead of starting a new topic

Q: There are 7 days in a week. To how many significant numbers is this 7?

A: Infinity, because the number of days in a week is known to infinite precision.
B: 3, because results are generally given to three significant figures. So when your parents tell you there are 7 days in a week they really mean 7.00 days in a week, and anything smaller than that is too insignificant for us to notice.
C: Both answers above are wrong, because if it's infinite then we'd be writing 7.00000000...; also, nobody writes 7.00 days in a week while reporting the number of days in a week. The correct answer should be 1.
D: The question itself is stupid. When doing experiments you measure things like concentration, which you know only to a limit of precision, and that's when you use significant numbers. But nobody ever measures the number of days in a week - we already know it! Significant numbers mean the same to days-in-a-week the same time means to the distance from here to London - it simply isn't relevant.

****

One of my professors set an exam question that said, 'set an exam question that I might use in future exams'. I wrote something similar to the above. I think it's a good question, but nonetheless I wonder what the spread of answers would be like - if nobody can answer it correctly it's probably too obscure a question, and better not asked in an exam.

[Pitsu]

Q: There are 7 days in a week. To how many significant numbers is this 7?

Read many times and still not sure,whether I get the question, but would vote for C. Although if you define week length as the length of 7 days, not through any other (SI or not) units, you could also go for A.

[Corribus]

Sorry, but D.

Significant figures are useful to discuss the precision of experimental methodologies. They have no relevance to what are simply defined terms. A better way to say this is that since the # of days in a week is not determined experimentally, but is rather a (mostly arbitrarily) defined value, significant figures have no relevance. We could just as easily define a week as having 8 days. The only reason you would specify significant figures for such a quantity is if you were trying to measure the value using an experiment. But that would be silly.

[Pol]

I'm going for D too. Although question doesn't sounds too clear for me (means I cannot imagine other choice than D for it, from the very beginning), maybe you could rephrase. I sense that you tried to say something else..

[Ethric]

I go for option E: a sound whack on the head for speaking gibberish.

[Gaidal Cain]

I think using days in a week is a bad idea for this kind of question, since it hardly ever matters. A more interesting question would be to use the speed of light, which is a defined quantity where the value certainly matters.

[Pitsu]

Significant figures are useful to discuss the precision of experimental methodologies. They have no relevance to what are simply defined terms.

Yes, experimental values are where the use of significant numbers is the most significant. But are you sure that pi or the base of natural logarithm or number of days in week, which have precise mathematical definition have nothing to do with the number of significant figures? They may be used as a rounded version of themselves (significant digits< infinity) or with infinite precision. In later case you do not need to count on them in arithmetics, since the values with lowest significant digits determine the digits in answer and infinity cannot be the lowest. IMO, although mainly used in analysis of experimentally obtained values, the rules of counting and arithmetics of significant figures can be applied to any number. It is mathematical data handling that is independent of experiment.

[Corribus]

The number of significant figures used for pi is meaningless, UNLESS you are determining it experimentally. In principle, we can determine pi to any degree of precision we want, because it is a mathematical definition. A computer can spit it out to fifty thousand decimal places, which is far, far, far better precision than we could ever determine experimentally. However, if in geometry class I was told to measure pi using a ruler and a compass, then significant figures become important. It would be wrong to report my answer as 3.14159265 when the best I could really measure using my instruments is 3.14. Only as they pertain to experimental measurements are significant figures important.

[Pitsu]

The number of significant figures used for pi is meaningless, UNLESS you are determining it experimentally.

If you measure circle diameter with precision of 6 significant digits and use it for calculating circle length. You take pi = 3.14. Is it correct to report the circle length with 6 significant digits? Imagine that you are not doing it as a 6th grade student but as a scientist. And if the digits do not matter for pi, then why take 3.14, it is much simpler to calculate with 3 and still give the answer with 6 digit precision and pretend it to reflect the reality.

EDIT. experimental values may have a deviation from the correct value. 3.14 for pi *has* a deviation, making it impossible to use this particular value for higher precision than 3 significant digits. As I said, the number of significant figures for integer counts, arbitrarily defined constants etc. can be ignored since it is infinite and only the lowest precision counts. (Experiment is as precise as the most erroneous step in it, infinitely precise operation adds no errors). Once you round the constants or counts or whatever up or down, they will have a limited number of significant digitals, which you already have to count. Thus, IMO, the main question is whether a week is defined as 7 days (seems to be the case) or are week and day two independent functions of second, year and moon phase.

[Heretic_Cata]

My first thought when reading the question was: "Who the **** cares ?"
But i guess:

The question itself is stupid.

is close enough.