Explanation:
To determine if the statement is true or false, we need to compare the population in 1820 and 1999.
- In 1820, the estimated global population was around 1 billion.
- In 1999, the estimated global population was around 6 billion.
Calculation:
- Population in 1820: 1 billion
- Population in 1999: 6 billion
The population in 1999 is 6 times greater than the population in 1820.
Therefore, the statement that the population of the world doubled between 1820 and 1999 is false.

Explanation:

The statement "The population of the world doubled between 1820 and 1999" is false.

Reasons:

1. Population Growth: The world population did not double between 1820 and 1999. In fact, the world population increased more than sixfold during this period. According to the United Nations, the estimated global population in 1820 was around 1 billion, and by 1999, it had reached approximately 6 billion.

2. Historical Population Data: Historical population data supports the fact that the world population did not double during this time frame. According to estimates, the world population reached 2 billion around 1927, which is more than a century after 1820. By 1960, it had already surpassed 3 billion. Therefore, by 1999, the population had increased by more than double.

3. Rate of Population Growth: The rate of population growth has been increasing over time, especially with advancements in healthcare, sanitation, and agricultural practices. The doubling time of the world population has been decreasing. It took around 123 years (from 1820 to 1943) for the population to double from 1 billion to 2 billion. However, it only took 39 years (from 1960 to 1999) for the population to double from 3 billion to 6 billion.

4. Impact of Industrial Revolution: The period between 1820 and 1999 saw significant advancements in technology and the Industrial Revolution. These developments led to improved living conditions, increased life expectancy, and a decrease in mortality rates. As a result, the population grew at a faster rate than in previous centuries.

Therefore, based on historical data and population growth trends, it is clear that the world population did not double between 1820 and 1999. Instead, it increased more than sixfold during this time period.