Why?



Scientific Notation is used to show a very large number or a very small number in a simpler form. An example of this would be the distance of the Sun from the Earth which is 93,000,000 miles. An easier way to write it would be 9.3 * 10 to the seventh power miles.


sun_and_earth.JPG

In the same way, the diameter of an atom could be written as 0.00000011811023622 inches or 1.1811023622 * 10 to the negative eighth power inches wide. In a way, it is like a mathematical short hand.

How to



If you have the number, 15,000,000, the decimal point is after the last zero. To change it to scientific notation, you move the decimal point to the left until the number is less than ten and greater than or equal to one. After that, you count the number of spaces the decimal moved and that is the power of ten making 15000000= 1.5 * 10 to the seventh power. In the same way if the number is a decimal, you move the decimal point to the right until the number is less than ten and greater than or equal to one. Then count the number of spaces the decimal moved, make that number negative, since it was a decimal, and that number is the power of ten. Following those steps, 0.000000000000875 becomes 8.75 * 10 to the negative thirteenth power.