Scientific notation is a way of expressing very large or very small numbers in a more concise and standardized format. It is typically written in the form of a number between 1 and 10 multiplied by a power of 10. For example, the number 3,000,000 can be written in scientific notation as 3 x 10^6, and the number 0.000005 can be written as 5 x 10^-6. This notation makes it easier to work with extremely large or small numbers in calculations and comparisons.