It's about nine-tenths as big as a Human Stomach
It's about one-and-one-fifth times as big as an Ostrich Egg
In other words, 0.50 gallons is 1.160 times the size of an Ostrich Egg, and the size of an Ostrich Egg is 0.86210 times that amount.(Struthio camelus) (for common ostrich; average)
The largest egg produced by living birds, ostrich eggs measure about 0.42270 gallons 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, the size of The Blood in a Human Body is 3 times 0.50 gallons.(for 70 kg body; average altitude; average)
The volume of blood in the average human body is about 1 gallons. Persons living at high altitude, however, may have up to an additional 0.50 gallons of blood to compensate for the lower oxygen level.
It's about one-third as big as a Bowling Ball
In other words, 0.50 gallons is 0.359191941580 times the size of a Bowling Ball, and the size of a Bowling Ball is 2.78402682310 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 1.39201341150 gallons. 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 times as big as a STARBUCKS Venti Coffee
In other words, 0.50 gallons is 3.20 times the size of a STARBUCKS Venti Coffee, and the size of a STARBUCKS Venti Coffee is 0.310 times that amount.A STARBUCKS Venti coffee drink measures 0.160 gallons. The name of the size, Venti, is the Italian word for twenty.
It's about one-fourth as big as a Basketball
In other words, 0.50 gallons is 0.266420066320 times the size of a Basketball, and the size of a Basketball is 3.75347102720 times that amount.(NBA official ball standards, Size 7)
A NBA official ball, manufactured by Spalding, is a Size 7 ball and measures about 1.87673551360 gallons. 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