Logarithmic scale
June 3, 2026
by
TCAR Education Programs, Stephen Von Weller
A tool to measure an exponential increase or decrease in a value. Both pH and earthquakes are measured on logarithmic scales. Small changes in a number reflect large changes in the item being measured. For example, a pH of 4 is 10 times as acidic as a pH of 3, and an earthquake with a magnitude of 7 has 10 times the force of a magnitude 6 quake. PRONUNCIATION: LOG-a-RITH-mic.