What Is Scientific Notation?
Scientific notation is a way of expressing very large or very small numbers in a compact form. A number in scientific notation is written as a × 10n, where the coefficient a is a number with exactly one non-zero digit to the left of the decimal point (1 ≤ |a| < 10), and n is an integer exponent.
How to Convert to Scientific Notation
- Move the decimal point so that only one non-zero digit remains to its left.
- Count the number of places you moved the decimal point — this becomes the exponent n.
- If you moved the decimal to the left, the exponent is positive.
- If you moved the decimal to the right, the exponent is negative.
Examples
Large Number
Speed of light: 300,000,000 m/s
Small Number
Diameter of an atom: 0.0000000001 m
Negative Number
Electron charge: -0.00000000016 C
Number Between 1 and 10
The number 5.5 is already in range
Avogadro's Number
602,200,000,000,000,000,000,000
Planck's Constant
0.0000000000000000000000000000000006626
Applications of Scientific Notation
- Physics: Expressing physical constants, distances, and measurements at extreme scales.
- Chemistry: Avogadro's number, molar masses, atomic and molecular dimensions.
- Astronomy: Distances between stars, galaxies, and other celestial objects.
- Engineering: Electrical values (picofarads, megaohms), signal frequencies.
- Biology: Cell sizes, microorganism counts, DNA base pair lengths.
E-Notation
In many calculators and programming languages, scientific notation is written using E-notation. For example, 4.56 × 107 is written as 4.56e7 or 4.56E7. The "e" stands for "exponent" and indicates the power of 10.
Rules to Remember
- The coefficient must be between 1 and 10 (inclusive of 1, exclusive of 10).
- A positive exponent means the original number is large (greater than or equal to 10).
- A negative exponent means the original number is small (between 0 and 1).
- An exponent of 0 means the number is already between 1 and 10.
- Zero in scientific notation is simply 0 × 100.