Analogue versus Digital

Most of the quantities in nature that can be measured are continuous. Examples
include

• Intensity of light during the day: The intensity of light gradually increases as the sun rises in the morning; it remains constant throughout the day and then gradually decreases as the sun sets until it becomes completely dark. The change in the light throughout the day is gradual and continuous. Even with a sudden change in weather when the sun is obscured by a cloud the fall in the light intensity although very sharp however is still continuous and is not abrupt.

• Rise and fall in temperature during a 24-hour period: The temperature also rises and falls with the passage of time during the day and in the night. The change in temperature is never abrupt but gradual and continuous.

• Velocity of a car traveling from A to B: The velocity of a car traveling from one city to another varies in a continuous manner. Even if it abruptly accelerates or stops suddenly, the change in velocity seemingly very sudden and abrupt is never abrupt in reality. This can be confirmed by measuring the velocity in short time intervals of few milliseconds.

The measurable values generally change over a continuous range having a minimum and maximum value. The temperature values in a summer month change between 23 0C to 45 0C. A car can travel at any velocity between 0 to 120 mph.