How can Logarithms be applied to real life situations and examples?

[Niaboc67]

If I understand Logarithms correctly it is the orders of magnitude? Either exponentially growing or exponentially decaying. I've heard that exponential growth is the same as the growth of cancer cells. But what are some other real life applications/examples of logarithms?

Thank You

 

[mathman]

http://en.wikipedia.org/wiki/Logarithmic_spiral

Try the above.

 

[Pharrahnox]

Logarithms are present in many equations such as the Richter scale for earthquakes, and the Decibal scale for sound power. Also the pH scale for measuring acidity, and the various frequencies of sounds of musical notes.

They are just examples of equations involving logarithms, but hopefully it gives you an insight as to their use.

 

[paisiello2]

If you wanted to know the time t it would take for an investment P to reach a certain value A at an interest rate r compounded n times, the formula would be:

t = (1/n) log(A/P) / log(1+r/n)

 

[Chestermiller]

Here's an example from a current thread: https://www.physicsforums.com/showthread.php?t=743043 See Simon Bridge's post.

Chet