Shrinking lake

Grade level: 4 – 5th

Skills: Fraction

Related environmental issues: Excessive water extraction

Area level: Global (Central Asia)


The Aral Sea in central Asia had an area as large as 26,000 square miles and it was the world’s fourth largest inland lake. However, due to excessive water use for agriculture purposes, the size of the lake shrunk to 1/4 of the original size by 2004. It further shrunk to 1/10 of the original size by 2007.  Most of the vegetation and wildlife were killed because of the water loss.

  1. How big was the lake in 2004?
  2. How big was the lake in 2007?
  3. How many gallons of water were lost between 2004 and 2007?

Source: Wikipedia

Photo: Nature


Answer keys

  1. 6,500 square miles (26,000 x 1/4= 6,500)
  2. 30,400,000  galons (26,000 x 1/10 = 2,600)
  3. 3,900 gallons (6,500-2,600=3,900)