It's about 1,500,000 times as heavy as a Grain of Rice
In other words, the weight of a Grain of Rice is 0.000000710 times 0.0000000300 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 0.0000003 times as heavy as The CN Tower
In other words, 0.0000000300 megatonnes is 0.000000254430 times the weight of The CN Tower, and the weight of The CN Tower is 3,930,400 times that amount.(a.k.a. La Tour CN, a.k.a. Canadian National Tower, a.k.a. Canada's National Tower) (Toronto, Canada)
The CN Tower weighs approximately 0.117910 megatonnes. The Tower is home to the world's highest glass floor — a viewing area that allows visitors to look straight down 342 m (1,120 ft) to the ground below.
It's about 0.0000002 times as heavy as The Sears Tower
In other words, 0.0000000300 megatonnes is 0.00000014870 times the weight of The Sears Tower, and the weight of The Sears Tower is 6,725,000 times that amount.(officially "Willis Tower" as of 2009) (Chicago, Illinois)
The Willis Tower weighs approximately 0.20180 megatonnes. The outer wall surface of the Tower is covered with black anodized aluminum panels which would total 110,000 sq. m (28 acres) if laid out together.
It's about 7,000,000 times as heavy as a Grain of Sand
In other words, 0.0000000300 megatonnes is 6,800,000 times the weight of a Grain of Sand, and the weight of a Grain of Sand is 0.000000150 times that amount.(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.
It's about 8,000,000 times as heavy as a Sesame Seed
In other words, 0.0000000300 megatonnes is 8,240,000 times the weight of a Sesame Seed, and the weight of a Sesame Seed is 0.0000001210 times that amount.(Sesamum indicum)
A sesame seed weighs approximately 0.000000000000003640 megatonnes. The McDonald's Big Mac sandwich, which is well-known for its sesame seed top bun, accounts for the consumption of an estimated 0.000002010 megatonnes of sesame seeds each day.
It's about 0.00000009 times as heavy as The Empire State Building
In other words, 0.0000000300 megatonnes is 0.00000009060 times the weight of The Empire State Building, and the weight of The Empire State Building is 11,000,000 times that amount.(New York City, New York)
The Empire State Building weighs approximately 0.3310 megatonnes. About 4% of the building's weight is its 6,000 cu. m (200,000 cu. ft) of limestone façade.
It's about 0.00000004 times as heavy as The Golden Gate Bridge
In other words, 0.0000000300 megatonnes is 0.00000003730 times the weight of The Golden Gate Bridge, and the weight of The Golden Gate Bridge is 26,800,000 times that amount.(San Francisco, California and Marin County, California) (Post 1986 weight reduction; total weight of bridge, anchorage, and approaches)
Following the completion of the 1986 project to eliminate excess material, the total weight of the Golden Gate Bridge — including its anchorages and approaches — is 0.8050 megatonnes. The two main cables in the spanning the bridge are spun out of a total of 129,000 km (80,200 mi) of wire.