EQ: Why do we need to use significant figures in scientific calculatioins?

SIG FIGS!!!

COPY THESE NOTES UNDER A NEW TOPIC. TOPIC #5 “SIGNIFICANT FIGURES”

1. Non-zero digits and zeros between non-zero digits are always significant.

2. Leading zeros are not significant.

3. Zeros to the right of all non-zero digits are only significant if a decimal point is shown.

4. For values written in scientific notation, the digits in the coefficient are significant.

5. In a common logarithm, there are as many digits after the decimal point as there are significant figures in the original number.

LET’S PRACTICE!!!

• 45.8736

• .000239

• .00023900

• 48000. 00

• 48000

• 3.982106

• 1.00040

• 12046000

HOW MANY SIG FIGS HERE?

• 3401• 2100• 2100.0• 5.00• 0.00412• 8,000,050,000

• 4• 2• 5• 3• 3• 6

WHAT ABOUT CALCULATIONS USING SIG FIGS???

• There are 2 rules we need to follow:• RULE #1: (For addition and subtraction only)

Round your answer of your calculation to the least number of DECIMAL places.

• RULE #2: For multiplication and division only) Round your answer to the LEAST number of SIGNIFICANT FIGURES.

ADD/SUBTRACT EXAMPLES• 2.45cm + 1.2cm = 3.65cm,

• Round off to = 3.7cm

• 7.432cm + 2cm = 9.432 round to 9cm

MULTIPLICATION EXAMPLE

• 56.78 cm x 2.45cm = 139.111 cm2

• Round to 139cm2

•75.8cm x 9.6cm = ?