MEASURING SOUND
- Standard unit: decibels
- Decibel scale: reflection of the logarithmic response of the human ear to changes in sound intensity
- Measured by first assigning an intensity I0 to a soft sound
- Equation:
CHEMISTRY
- Solution's pH defined by
- t= hydronium ion concentration in mol/liter
- Round pH values to the nearest 10th
- Radioactive decay
- Used for geology
- Half-life: time taken for the radioactivity of a specified isotope to fall to half its original value
- Carbon dating
- Radiometric dating technique
- Estimates age of organic materials
- Willard Libby
EARTHQUAKES
- Magnitude of an earthquake is logarithmic
- Used for predicting coming earthquakes
- Richter Scale: base-10 logarithmic scale
POPULATION GROWTH
- Natural logarithms and exponential functions to determine increments of certain measurements
- Measured to predict death rates, population increments, regional birth/death rates
- Can be expanded into weeks, days, years, etc.
ECONOMICS
- Make linear/exponential relationships
- Analyzes the growth rate relationship of variables
- Natural logarithm: grows at a constant percentage rate; log of variable will grow as a function of time
- Finance: interest rates, stock prices, value of currency
BENFORD'S LAW
- Frank Benford: American physicists
- First-digit law
- Frequency distribution of digits in numerous sources of data
- Applicable in:
- Street adresses
- Stock prices
- Death rates
- Physical/mathematical constants
Logarithms in Real Life Applications
Joey Uy: The Preuss School UCSD
March 18, 2014; 1:05 P.M., EST