1. Scientific notation is a way to write numbers as a product of a coefficient and a power of 10 to express very large and very small numbers. 2. A law is a statement of fact based on repeated observation that describes natural phenomena, while a theory is a well-substantiated explanation of such a law. 3. Significant figures indicate the precision or uncertainty of a measurement and are used to calculate the error in products and quotients of calculations.

1. Warm-up Which number is the largest? a. 1.13 x 10 9 b. 3.51 x 10 3 c. 5.88 x 10 5 d. 7.92 x 10 2 Which unit can be used to measure volume? a. m b. m 2 c. m 3 Which of the following units is the longest? a. meter b. centimeter c. kilometer d. millimeter

2. 1-3 Scientific Notation Perform calculations involving scientific notation. Determine significant figures.

4. Law vs. Theory Law – a rule of nature Answers the question “what?” Examples: Law of Attraction and Repulsion, Law of Universal Gravitation Theory – An explanation based on repeated experimentation and observation. Answers the question “why” Examples: Theory of Evolution, Atomic Theory

5. Law vs. Theory Theories do not become laws!!! What doesn’t replace why! A theory represents everything currently known about a topic.

6. Scientific Notation A number written as a product of two numbers: a coefficient and a power of 10 Designed for the expression of very big and very small numbers 3.6 x 10 4 1 gram of hydrogen contains 301,000,000,000,000,000,000,000 molecules 3.01 x 10 23 molecules 0.00081 = 8.1 x 10 -4 Decimal moves 4 place to the right 34,000 = 3.4 x 10 4 Decimal move 4 places to the left

7. Significant Figures A method of expressing error in measurement. Measure a value and then estimate one degree below the limit of the reading . 5.35 cm

8. Significant Figures Atlantic – Pacific Rule Pacific – "P" is for decimal point is present Count significant digits starting with the first non-zero digit from the left. 0.004703 has 4 significant digits. 18.00 also has 4 significant digits. Atlantic – "A" is for decimal point is absent . Start counting significant digits with the first non-zero digit from the right. 140,000 has 2 significant digits. 20060 has 4 significant digits.

9. Examples 50.3 3 SF 0.0008 1 SF 200200 4 SF 57.00 4 SF 490 2 SF 10000000 1 SF

10. 1-3 Summary What is scientific notation? Scientific notation is used to express very large or very small numbers. What are significant figures? Significant figures tell us how important the numbers are.