1. The largest number is 1.13 x 109. 2. Volume can be measured in m3. 3. The longest unit is kilometer.

1. Warm-up Which number is the largest? a. 1.13 x 109b. 3.51 x 103c. 5.88 x 105d. 7.92 x 102 Which unit can be used to measure volume? a.mb. m2c. m3 Which of the following units is the longest? a. meterb. centimeterc.kilometerd. millimeter

2. 1-4 Scientific Notation Compare and contrast scientific theories, and scientific laws. Use numbers involving scientific notation. Determine significant figures.

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

5. Scientific Notation Designed for the expression of very big and very small numbers 3.6 x 104 1 gram of hydrogen contains 301,000,000,000,000,000,000,000 molecules 3.01 x 1023molecules a coefficient and a power of 10 Exponent represents number of places decimal moved. 0.00081 = 8.1 x 10-4 Number is smaller than 1 – negative exponent 34,000 = 3.4 x 104 Number is greater than 1 – positive exponent

6. Sci. Not. Practice 62900 6.29 x 104 0.00028 2.8 x 10-4 1720000 1.72 x 106 0.0753 7.53 x 10-2

7. Significant Figures A method of expressing error in measurement. Measure a value and then estimate one digit below the smallest unit on the tool. 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. 1-4 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.