LESSON 5 Scientific Notation! (Say whaaat?)
Scientific Notation & S.D.- Accuracy and precision is very important in science
- Important to communicate this accuracy carefully
- Calculators = not smart enough to decide what is/what is not precise
- Scientists have est. rules for rounding off extra digits; YOU MUST FOLLOW THEM!
(π r^2)(h) -> π (0.8)^2(13.2) = 26.540174... 8 SDs present
Significant Digits
- Non-zero digits are always significant
- If zero is a place keeper, it is generally NOT significant
ie. 0.0031
- Any numbers to the left of a decimal point are SIGNIFICANT
ie. 2.00, 23.05, 13.900
- Zeros after another number are SIGNIFICANT
ie. 3.000, 0.00000120, 3.014, 1.120
- When adding or subtracting round to the least precise number
ie. 7.4212 - 3.54 = 3.8812 -> 3.88
12.3 + 10.771 = 23.071 -> 23.1
- When you multiply or divide, round to the number with fewest SDs
1.33421 x 19.531 = 26.058434551 -> 26.058
- Constants (π, G, ect) on your data sheet have infinite SDs
Scientific Notation
- Used if we need to write the number 1000 with only 2 SDs
- Used if we want to write the number 22 billion 1 hundred million w/o taking up an entire line
> ie. 22,100,000,000
= 2.21 x 10^10
= 2.2 x 10^10
= 2.210 x 10^10
- Shows really big or really small numbers easily
- Makes use of power of 10
Calculators
- Your calculator has funtions that you can use easily
> 3.24 E-5 RIGHT :)
> (3.24)(10^5) WRONG :(
SIGNIFICANT
DIGITS ♥ ✔
(dang they're cool)
~ kim nipp
DIGITS ♥ ✔
(dang they're cool)
~ kim nipp
posted by chemistry11 @ 11:03 AM
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