It's about one-seven-hundredth as heavy as a Can of Soup.
In other words, 491 miligrams is 0.0014 times the weight of a Can of Soup, and the weight of a Can of Soup is 710 times that amount.(for Campbell''s Condensed Tomato Soup, 317.9 ml)
A can of Campbell''s Tomato Soup weighs 350,000 miligrams. 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 800 times as heavy as a Grain of Sugar.
In other words, 491 miligrams is 786 times the weight of a Grain of Sugar, and the weight of a Grain of Sugar is 0.00127 times that amount.(a.k.a. white sugar, a.k.a. white refined sugar, a.k.a. table sugar, a.k.a. sucrose, a.k.a. saccharose)
A grain of sugar weighs approximately 0.625 mg. Sugar consumption varies widely by country; the average citizen of the United States consumes about 61,200,000 miligrams of sugar each year.
It's about one-eight-hundred-fiftieth as heavy as a Football (American).
In other words, 491 miligrams is 0.001194449332224 times the weight of a Football (American), and the weight of a Football (American) is 837.2058764 times that amount.(a.k.a. "pigskin") (NFL standard)
Per National Football League official rules, an American football must weigh between 396,893.32375 miligrams and 425,242.846875 miligrams. 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-nine-hundredth as heavy as a Football (Soccer).
In other words, 491 miligrams is 0.0011 times the weight of a Football (Soccer), and the weight of a Football (Soccer) is 910 times that amount.(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 410,000 miligrams and 450,000 miligrams. 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-one-thousand-five-hundredth as heavy as a Basketball.
In other words, 491 miligrams is 0.00078725069624 times the weight of a Basketball, and the weight of a Basketball is 1,270.2433987 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 623,689.50875 miligrams. These balls have 4,118 pebbles each with a diameter of 2.5 mm
It's about 1,500 times as heavy as a Poppy Seed.
In other words, the weight of a Poppy Seed is 0.00063 times 491 miligrams.(Papaver somniferum)
Fifty percent oil by weight, a poppy seed weighs approximately 0.3 mg. The true pigment of a poppy seed is brown in color, while the characteristic bluish color is an optical illusion caused by a layer of calcium oxalate crystals refracting light rays.
It's about one-two-thousandth as heavy as a liter of Water.
In other words, 491 miligrams is 0.0004909863 times the weight of a liter of Water, and the weight of a liter of Water is 2,036.717 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 1,000,028 miligrams 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).