# A Logarithmic scale for the Laser Intensity.

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1. Aug 28, 2016

### Amany Gouda

I drawed a relation between the growth rate of the material to the laser intensity.
After drawing, My professor told me that I must convert both values of the growth rate and the laser intensity to their values in the logarithmic scale.
I don't know how.
May I get a help.

2. Aug 28, 2016

### sophiecentaur

This sort of treatment of data is common amongst experimenters because it presents the data in a more readable graphical form. It looks like gobbledegook when you are not familiar with the process or the reasons for doing it but it is worth getting familiar with it.
Draw up a table of the results with an added column for each variable in which you put the log of the values - simple as that. Plot the values in the two extra (log) columns on ordinary graph paper. Mark the Axis labels "Log(growth rate)" and Log(intensity)" and don't worry about the fact that the actual numbers don't appear to make much sense. It will probably spread the points out nicely, compared with plotting on a linear scale.
Hint: If you can use a spreadsheet then this sort of thing is very convenient as you can easily plot graphs of the combinations of linear and logarithmic scales for each variable. It's very handy to do this sort of thing because it can often show you a straight line for one of the graphs. Get Into Spreadsheets!!!

3. Aug 28, 2016

### lychette

print off some log-log and log-linear graph paper...plot your data...straight lines guaranteed

4. Aug 28, 2016

### Amany Gouda

Thank you for your explanation , it is too easy explanation.
but I was wondering if I should take log to the final results go the growth rate and laser intensity only or I should take the log over all internal calculation to get the growth rate?
Thank you

Last edited by a moderator: May 8, 2017
5. Aug 29, 2016

### sophiecentaur

If you know the law, connecting variables then you can choose correctly. If not then just try all the combinations. You should seriously consider getting into spreadsheets, over 30 years ago, a colleague urged me to use one ( on a BBC Micro!!). They are available everywhere and make it so easy to experiment with data.
Much more use and at least as much fun as a computer game.

Last edited by a moderator: May 8, 2017