Chemistry July 3, 2008 1st Qtr

Scientific Measurement

Scientific figures in measurement
*The numbers reported in a measurement are limited by the measuring tool
*Significant figures in a measurement include the known digits plus one estimated digit

Counting Significant Figures
38.15 cm -- 4
5-6 ft -- 2
All non zero digits in a measured number are significant

Heading Zeroes
0.008m -- 1
0.015607-- 8
Leading zeroes in decimal numbers are not significant

Sandwiched zeroes
50.8 mm -- 3
2001 minutes -- 4
Zeroes between non zero numbers are significant

Trailing zeroes without decimal
25,000 in -- 2
200 yr -- 1
Trailing zeroes in numbers without decimals are not significant if they are serving as place holders

Trailing zeroes with decimal
34.000 in -- 5
201.00 in -- 5
Trailing zeroes in numbers with decimals are significant

Significant numbers in calculations
-A calculated answer can't be more precise than the measuring tool