It's about as big as a Human Stomach
It's about one-and-one-fourth times as big as an Ostrich Egg
In other words, 20 deciliters is 1.225 times the size of an Ostrich Egg, and the size of an Ostrich Egg is 0.8163 times that amount.(Struthio camelus) (for common ostrich; average)
The largest egg produced by living birds, ostrich eggs measure about 16 deciliters in volume. The eggs take about nine weeks to hatch, with males and females taking turns incubating them.
It's about two-fifths as big as The Blood in a Human Body
In other words, 20 deciliters is 0.4 times the size of The Blood in a Human Body, and the size of The Blood in a Human Body is 3 times that amount.(for 70 kg body; average altitude; average)
The volume of blood in the average human body is about 50 deciliters. Persons living at high altitude, however, may have up to an additional 20 deciliters of blood to compensate for the lower oxygen level.
It's about two-fifths as big as a Bowling Ball
In other words, 20 deciliters is 0.3795538896 times the size of a Bowling Ball, and the size of a Bowling Ball is 2.6346719857 times that amount.(USBC specifications; tenpin)
According to United States Bowling Congress specifications, a tenpin bowling ball should measure at least 10.795 cm (4.25 in) in radius for a total volume of about 52.6934397150 deciliters. Because regulation balls measure the same diameter irrespective of their weight, ball density varies by size and balls weighing less than about 5 kg (11 lbs) will float in water.
It's about three-and-a-half times as big as a STARBUCKS Venti Coffee
In other words, 20 deciliters is 3.4 times the size of a STARBUCKS Venti Coffee, and the size of a STARBUCKS Venti Coffee is 0.29 times that amount.A STARBUCKS Venti coffee drink measures 5.90 deciliters. The name of the size, Venti, is the Italian word for twenty.
It's about three-tenths as big as a Basketball
In other words, 20 deciliters is 0.28152294283 times the size of a Basketball, and the size of a Basketball is 3.5521083644 times that amount.(NBA official ball standards, Size 7)
A NBA official ball, manufactured by Spalding, is a Size 7 ball and measures about 71.042167287 deciliters. The surface of these balls have 4,118 pebbles with a diameter of 2.5 mm each.
It's about four times as big as a Blood Donation
In other words, 20 deciliters is 4 times the size of a Blood Donation, and the size of a Blood Donation is 0.3 times that amount.(American Red Cross donation volume)
The typical donation amount when giving blood is about 5 deciliters. Donated quantities of blood typically have a viable shelf life of about 42 days.