Scientific Measurements and Significant Figures

(SI) Mass

kilogram (kg)

(SI) Length

meter (m)

(SI) Time

second (s)

(SI) Temperature

Kelvin (K)

(SI) Amount of a substance

mole (mol)

(SI) Electric current

ampere (A)

(SI) Luminous intensity

candela (cd)

365.24 day

1 year

Copper density

8.96 g/cm3.

Unknown alloy density

4.28 g/cm3. Volume of 9.99g sample: 2.33mL

Density calculation

What is the density (kg/L) of a sample with a mass of 5.2 lbs and a volume of 0.45 gal?

Density calculation practice

What is the density (kg/L) of a sample with a volume of 0.100 gal and a mass of 8.5 oz? 0.64 kg/L

Rare steak cooking temperature

between 120F and 125 F.

Convert 120F

to C and K.

Convert 125F

to C and K: +51.7 C, 324.8K

Counting Significant Figures

Nonzero integers are always significant.

Exact numbers

have an infinite number of significant figures.

Leading zeros

do not count as significant figures.

Captive zeros

count as significant figures.

Trailing zeros

are significant if the number contains a decimal point.

Rounding rule

If the digit to be removed is less than 5, the preceding digit stays the same.

Rounding rule

If the digit to be removed is greater than 5, the preceding digit is increased by 1.

Rounding rule

If the digit to be removed is exactly 5, the preceding digit remains the same or increases by 1, whichever gives an even digit.

Significant figures in multiplication and division

The number of significant figures in the result equals the number of significant figures in the least precise number used in the calculation.

Significant figures in addition and subtraction

The decimal place where uncertainty begins in the least precise number used in the calculation is where uncertainty begins in the answer.

tera T

10^12

giga G

10^9

mega M

10^6

kilo k

10^3

deci d

10^-1

centi c

10^-2

mili m

10^-3

micro (mu)

10^-6

nano n

10^-9

pico p

10^-12