It's about one-one-hundredth as heavy as a Grizzly Bear
In other words, 0.00000000500 megatonnes is 0.0096 times the weight of a Grizzly Bear, and the weight of a Grizzly Bear is 104 times that amount.(a.k.a. brown bear, a.k.a. silver bear, Ursus arctos horribilis) (Adult, male, coastal area population average)
An adult, male grizzly bear from a coastal area (where food is plentiful) can weigh up to 0.0000005210 megatonnes. In spite of their tremendous size, grizzly bears can run at speeds of up to 55 kph (34 mph).
It's about 100 times as heavy as a Golf Ball
In other words, 0.00000000500 megatonnes is 108.90 times the weight of a Golf Ball, and the weight of a Golf Ball is 0.009183 times that amount.(per R&A USGA Rules of Golf; maximum rule weight)
According to the Rules of Golf (as approved by the United States Golf Association and the Rules Committee of the Royal and Ancient Golf Club of Saint Andrews), golf balls must weigh no more than 0.000000000045930 megatonnes. Golf balls are not required to have the familiar dimpled pattern, but the design has been popular since its invention in 1905 because it reduces drag while increasing lift.
It's about one-one-hundred-fiftieth as heavy as a Cow
In other words, the weight of a Cow is 140 times 0.00000000500 megatonnes.(for Holstein, a.k.a. Holstein Friesian, a.k.a. Friesian, Bos primigenius) (adult, heifer)
A mature Holstein cow (the well-known black-and-white, spotted breed of cow) typically weighs 0.000000680 megatonnes. President William Howard Taft (1909 - 1913) kept a Holstein cow named Pauline Wayne on the White House grounds — a gift from a Wisconsin senator and the source of the First Family's milk.
It's about 150 times as heavy as a Light Bulb
In other words, the weight of a Light Bulb is 0.0067 times 0.00000000500 megatonnes.(a.k.a. lamp) (for A19-size, 60w, incandescent bulb by Bulbrite; package weight)
A standard, sixty-watt light bulb weighs about 0.0000000000340 megatonnes. The tightly-coiled filament inside a bulb of this size would measure about 579mm if uncoiled and stretched out.
It's about 200 times as heavy as a Battery (AA)
In other words, 0.00000000500 megatonnes is 210 times the weight of a Battery (AA), and the weight of a Battery (AA) is 0.0048 times that amount.(Alkaline)
An "AA" size battery weighs 0.0000000000240 megatonnes. AA batteries came into common use during World War II and were given their name by the American National Standards Institute (ANSI) Committee C18 because they were smaller than the "A" size batteries which were invented first.
It's about 250 times as heavy as a Mouse
In other words, the weight of a Mouse is 0.0042 times 0.00000000500 megatonnes.(a.k.a. "House mouse", Mus musculus) (adult)
The weight of a mouse is typically an average of 0.0000000000210 megatonnes. While most mice typically live two to three years, the Methuselah Mouse Prize — an award administered by a non-profit organization which advances aging-related research — was once awarded to a team of scientists whose research resulted in a mouse living just under five years.
It's about 350 times as heavy as a Compact disc