It's about one-nine-thousandth as heavy as The Tongue of a Blue Whale
In other words, 0.000000000310 megatonnes is 0.00011 times the weight of The Tongue of a Blue Whale, and the weight of The Tongue of a Blue Whale is 9,100 times that amount.(Balaenoptera musculus) (adult)
The tongue of a Blue Whale can weigh up to 0.00000270 megatonnes. Despite their tremendous size, blue whales feed almost exclusively on tiny crustaceans called krill and cannot swallow anything much larger than a beach ball.
It's about one-ten-thousandth as heavy as a Hippopotamus
In other words, 0.000000000310 megatonnes is 0.00008270 times the weight of a Hippopotamus, and the weight of a Hippopotamus is 12,100 times that amount.(Hippopotamus amphibius) (adult, male)
The average weight of an adult male hippopotamus ranges from 0.000003750 megatonnes. Appearances to the contrary, adult hippos cannot swim or float in water; they actually move by leaping and walking across lake bottoms at about 8 kph (5 mph).
It's about 15,000 times as heavy as a Grain of Rice
In other words, the weight of a Grain of Rice is 0.0000670 times 0.000000000310 megatonnes.(conventional; US; long-, medium-, and short-gran varieties; uncooked)
With great differences in variety, the average among a sampling of common short-, medium- and long-grain rices finds that a single grain weighs about 0.0000000000000210 megatonnes before cooking. A staple through most of human history, archaeological evidence indicates that the earliest rice cultivation was about 11,500 years ago.
It's about one-twenty-thousandth as heavy as an Elephant
In other words, the weight of an Elephant is 20,000 times 0.000000000310 megatonnes.(for African bush elephant, Loxodonta africana) (Adult, bull)
A bull African bush elephant weighs about 0.00000610 megatonnes. Among African elephants, both males and females have tusks (whereas female Asian elephants, Elephas maximus, do not have tusks) which can grow to 3 m (10 ft) and typically weigh about 0.00000400 megatonnes
It's about one-twenty-thousandth as heavy as a Tyrannosaurus rex
In other words, the weight of a Tyrannosaurus rex is 21,000 times 0.000000000310 megatonnes.(for FMNH PR2081, a.k.a. "Sue") (a.k.a. Tyrannosaurus, a.k.a. T-Rex) (estimated live weight)
The notable Tyrannosaurus specimen housed at the Field Museum of Natural History in Chicago, Illinois, "Sue," is estimated to have weighed about 0.00000640 megatonnes while alive. A renowned predator in popular culture, the teeth of tyrannosaurus rex were up to 33.02 cm (13 in) long.
It's about one-thirty-five-thousandth as heavy as an Anchor of a Cruise Ship
In other words, the weight of an Anchor of a Cruise Ship is 36,500 times 0.000000000310 megatonnes.(for QE2 forward anchor, a.k.a. RMS Queen Elizabeth 2)
Each of the forward anchors of the RMS Queen Elizabeth 2 weighs 0.00001130 megatonnes. The anchor of the QE2 now sits in front of the Holyrood Church in Southampton, England, United Kingdom, along a pedestrian tourist route known as "the QE2 mile."
It's about 70,000 times as heavy as a Grain of Sand
In other words, the weight of a Grain of Sand is 0.0000140 times 0.000000000310 megatonnes.(medium grain)
With tremendous variety in the size of grain and the component material, grains of sand weigh an average of 0.00000000000000440 megatonnes. In 2007, a team of seven in Myrtle Beach created the world's tallest sandcastle, which measured 15.10 m (49.55 ft) in height.