How do scientists express uncertainty in measurement?

ChemistryBC High SchoolKuzara

What is the length of the board?

…how about now?

Is this any better?

One last time…

Reporting measurements using significant figures

Reporting Measurements using significant figures

Rules for determining significant figures

How many significant figures?

1. 103 m2. 57.6080 s3. 0.024 g4. 120 kg5. 100.0 mL6. 250. km

Rules for Making Calculations with Significant Figures

Carry out the following calculations and report your answer with the correct number of significant figures.

Rules for Rounding

Round each value to three significant figures

1. 23.42 m2. 0.4059 s3. 45.75 L4. 110.59 g5. 23.851 kg

Putting a number into scientific notation All numbers, regardless of magnitude, can

be expressed in the form: N x 10n where 1<N<10 n is a positive or negative integer

When written in standard form there must be one digit, and only one digit to the left of the decimal point in the number N.

standard: 1.23 x 106 non-standard: 123 x 104

Positive Exponents 36,600 exponent of 10 is a positive whole

number value of the exponent = number of

places the decimal point must be moved so that the notation is in standard form.

36,600 x 100 Non-standard 3.66 x 104 Standard

Negative Exponents 0.00563 exponent of 10 is a negative whole

number value of the exponent = number of

places the decimal point must be moved so that the notation is in standard form

0.00563 x 100 Non-standard 5.63 x 10-3 Standard

Write each value in scientific notation.

Convert to Scientific Notation

1. 727 m2. 17200.0 s3. 0.000984 kg

1. 1.56 x 104 m2. 3.6 x 10-2 kg

Convert to Decimal Form

Rules for calculations with scientific notation.

Write this down!

NEVER EVERenter x 10 ^ into your

calculator!

Calculate

Calculate

Calculate

SI Base Units

SI Unit Prefixes