It's about as big as a Human Stomach.
It's about one-and-one-fifth times as big as an Ostrich Egg.
In other words, 400 teaspoons is 1.2080 times the size of an Ostrich Egg, and the size of an Ostrich Egg is 0.82780 times that amount.(Struthio camelus) (for common ostrich; average)
The largest egg produced by living birds, ostrich eggs measure about 324.60 teaspoons 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 400 teaspoons.(for 70 kg body; average altitude; average)
The volume of blood in the average human body is about 1,000 teaspoons. Persons living at high altitude, however, may have up to an additional 400 teaspoons of blood to compensate for the lower oxygen level.
It's about two-fifths as big as a Bowling Ball.
In other words, 400 teaspoons is 0.374158272480 times the size of a Bowling Ball, and the size of a Bowling Ball is 2.67266575020 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 1,069.0663001 teaspoons. 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, the size of a STARBUCKS Venti Coffee is 0.30 times 400 teaspoons.A STARBUCKS Venti coffee drink measures 120 teaspoons. 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, 400 teaspoons is 0.277520902410 times the size of a Basketball, and the size of a Basketball is 3.60333218620 times that amount.(NBA official ball standards, Size 7)
A NBA official ball, manufactured by Spalding, is a Size 7 ball and measures about 1,441.33287450 teaspoons. 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.