Log scales use the same vertical distance to represent equivalent percent changes. For example an increase from $10 to $20 would be represented by the same distance on the chart as an increase from $50 to $100, because each change represents a 100% increase. The alternative is a Linear Scale which plots the same vertical distance for each unit change in price. For example a stock that had increased from $1 to $6 would be represented by the same distance on the chart as a stock that had increased from $50 to $55. Both stocks increased by $5 or 5 units, even though our first example is a 500% change, and our second is 10%.