Scientific notation is a way of writing numbers as the product of a number between 1 and 10 and a power of 10. It makes calculating very large and small numbers easier. The document provides steps for converting a number like 4,600,000,000,000 meters to scientific notation: place the decimal after the first non-zero digit, count places to determine the exponent, and write the number as a coefficient multiplied by 10 to that exponent power. Significant figures refer to the meaningful digits in a number written in scientific notation.