The study of matter allows us to encompass the known universe in a range of sizes and distances with the following lower and upper bounds:

• 0,000 000 000 000 001 m: the approximate size of an atomic nucleus.
• 100 000 000 000 000 000 000 000 000 m: the estimated diameter of the known universe.

In order to simplify the reading and writing of these numbers, scientists use a technique known as scientific notation, which consists in writing them as powers of ten.
The following visual illustrates how to express a number as a power of ten.