Significant Figures

What are significant figures?
- Also known as significant digits or simply "sig figs"
- They are certain digits in a measurement
- Associated with scientific notation and rounding

What are they important?
- A measurement can never be precise. We use sig figs and scientific notation to find a general number.

How do I know which are significant digits?
- Non-zero digits are sig figs
- Zeroes after the decimal point are sig figs
- Zeroes between 2 other significant digits are sig figs
- Leading Zeroes are NOT sig figs
- In scientific notation, all digits in front of the exponential term are sig figs

Rounding
- Digit > 5, the digit in front of it rounds up
- Digit < 5, the digit in front of it keeps the same. All numbers after the rounded digit disappear.
- Digit = 5 + non-zero digits behind it, round up.
- Digit = 5 + no numbers behind it, round to make the digit even.

http://www.sciencegeek.net/APchemistry/APtaters/chap02counting.htm
This is a practice test on counting significant digits. Test yourself to see if you know the stuff!

- by Catherine