It's about as heavy as a Football (Soccer).
In other words, the weight of a Football (Soccer) is 1 times 15 ounces.(a.k.a. Soccer, a.k.a. Association Football) (FIFA Law 2 specification)
According to FIFA's Law of the Game number 2, a football must weigh between 14 ounces and 16 ounces. An artifact on display at the Smith Art Gallery in Museum in Stirling, Scotland is said to be the world's oldest football and is about one-third to one-half the size of a modern football.
It's about one-and-one-tenth times as heavy as a Football (American).
In other words, 15 ounces is 1.034482758621 times the weight of a Football (American), and the weight of a Football (American) is 0.96666666666640 times that amount.(a.k.a. "pigskin") (NFL standard)
Per National Football League official rules, an American football must weigh between 14 ounces and 15 ounces. Because of NFL regulations, ceremonial considerations, and backup requirements, each NFL Superbowl requires the manufacture of 144 balls exclusively for the event.
It's about one-and-one-fifth times as heavy as a Can of Soup.
In other words, the weight of a Can of Soup is 0.830 times 15 ounces.(for Campbell''s Condensed Tomato Soup, 317.9 ml)
A can of Campbell''s Tomato Soup weighs 12 ounces. Cans have been used to store soup and other foods since their invention in 1913, but a dedicated can opener was not developed until cans began to use thinner materials — prior to that time, cans were usually opened using various blunt instruments and tools.
It's about one-and-two-fifths times as heavy as a Human Heart.
It's about two-thirds as heavy as a Basketball.
In other words, 15 ounces is 0.681818181820 times the weight of a Basketball, and the weight of a Basketball is 1.46666666670 times that amount.(NBA official ball standards, Size 7)
A regulation NBA basketball, manufactured by Spalding, is known as a Size 7 ball and weighs 22 ounces. These balls have 4,118 pebbles each with a diameter of 2.5 mm
It's about two times as heavy as a Hamster.
In other words, the weight of a Hamster is 0.50 times 15 ounces.(for Syrian hamster, a.k.a. golden hamster, a.k.a. Mesocricetus auratus; adult)
An adult Syrian hamster has a typical weight of about 7 ounces. Known for transporting food in the pouches of their cheeks so that they can bury it later, some hamsters can store up to 900 ounces of food in their borrows.
It's about two-fifths as heavy as a liter of Water.
In other words, 15 ounces is 0.42523090 times the weight of a liter of Water, and the weight of a liter of Water is 2.3516640 times that amount.(fresh; 4° C / 39.2° F; maximum density)
Contrary to popular belief, 1 liter (0.0.264172052358148 gal) of water at 4° C / 39.2° F (its point of maximum density) weighs 35.274950 ounces rather than 1 kg exactly. The total volume of water on the planet Earth is about 13,590,000,000,000,000,000 (13.59 quntillion) L (3,590,000,000,000,000,000 gallons).