# 6. Scientific Notation

**Scientific notation** **(also known as standard form)** is used for numbers that are either very large or very small, like the
following.

The distance from Earth to the nearest star system, Alpha Centauri, is about

39 900 000 000 000 000 m

Earth's mass is about:

6 000 000 000 000 000 000 000 000 kg

Red light has a wavelength of about

0.000 000 7 m

Scientific notation is a more convenient way of expressing such large or small numbers. It is used extensively in science and engineering, and makes life easier when working with large (or small) numbers on calculators or computers.

## Scientific Notation - Definition

A number in **scientific notation** is expressed as

P× 10^{k}

where: 1 ≤ *P* < 10 and *k* is an integer

### Example 1

(a) 340 000 000 (ordinary notation)

= 3.4 × 100 000 000

= 3.4 × 10

^{8}(scientific notation)

(b) 0.000 015 (ordinary notation)

= 1.5 ÷ 100 000

= 1.5 × 10

^{-5}(scientific notation)

(c) 68 250 000 (ordinary notation)

= 6.825 × 10 000 000

= 6.825 × 10

^{7}(scientific notation)

To change a number from scientific notation to ordinary notation, we simply reverse the procedure shown in the above examples.

### Example 2

Using scientific notation, we can write our earlier examples as:

Distance to Alpha Centauri:

39 900 000 000 000 000 m = 3.99 × 10^{16}mEarth's mass:

6 000 000 000 000 000 000 000 000 kg = 6 × 10^{24}kgWavelength of red light:

0.000 000 7 m = 7 × 10^{−7}m

### Example 3

We are all affected by slow Internet connections, but German scientists in 2011 succeeded in transmitting 26 terabits per second on a single laser beam. A "bit" is the smallest unit of information (a "0" or a "1"). That number is:

26 terabits = 26 000 000 000 000 = 2.6 × 10

^{13}bits

This is the equivalent of being able to transmit 700 DVDs per second!

### Example 4

(7 × 10^{11}) × (6 × 10^{-3})

= 42 × 10

^{8}(This is not in scientific notation!)= 4.2 × 10

^{9}

### Exercises

Perform the following calculations using a calculator, by first expressing all numbers in scientific notation:

(1) 0.000 058 × 4 000 000 000 000

Answer

0.000 058 × 4 000 000 000 000

= (5.8 × 10

^{−5}) × (4 × 10^{12})= 2.32 × 10

^{8}

[Considering the number of significant digits in the question, strictly our answer should be: 2 ×
10^{8},]

(2) 35 000 000 000 ÷ 0.000 000 000 000 07

Answer

35 000 000 000 ÷ 0.000 000 000 000 07

= (3.5 × 10

^{10}) ÷ (7 × 10^{−14})= 5 × 10

^{23}

[Note that a large number divided by a small number gives a very large number!]

Please support IntMath!

(3) 0.000 000 000 000 06 ÷ 53 000 000 000 000

Answer

0.000 000 000 000 06 ÷ 53 000 000 000 000

= (6 × 10

^{−14}) ÷ (5.3 × 10^{13})= 1.13207547 × 10

^{−27}

[Considering the number of significant digits in the question, strictly our answer should be: 1 ×
10^{−23}. Note also that a small number divided by a big number is a very small number.]

Get the Daily Math Tweet!

IntMath on Twitter

### Search IntMath, blog and Forum

### Online Algebra Solver

This algebra solver can solve a wide range of math problems.

Go to: Online algebra solver

### Algebra Lessons on DVD

Math videos by MathTutorDVD.com

Easy to understand algebra lessons on DVD. See samples before you commit.

More info: Algebra videos

### The IntMath Newsletter

Sign up for the free **IntMath Newsletter**. Get math study tips, information, news and updates each fortnight. Join thousands of satisfied students, teachers and parents!