It's about 6,500 times as heavy as a Battery (C)
In other words, 420 kilograms is 6,500 times the weight of a Battery (C), and the weight of a Battery (C) is 0.0002 times that amount.(Alkaline)
A "C" size battery weighs 0.065 kilograms. C batteries are typically used in medium-drain devices such as musical instruments.
It's about 7,500 times as heavy as a Tennis Ball
In other words, 420 kilograms is 7,280 times the weight of a Tennis Ball, and the weight of a Tennis Ball is 0.00014 times that amount.(ITF Standard; for Type 2 ball)
Per International Tennis Federation standard, regulation tennis balls must weigh about 0.0577 kilograms. Competition balls are also tested for bounce height, with the standards requiring that a ball dropped from 254 cm must bounce back to a height of 135 cm to 147 cm.
It's about 9,000 times as heavy as a Golf Ball
In other words, 420 kilograms is 9,144 times the weight of a Golf Ball, and the weight of a Golf Ball is 0.000109 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 0.04593 kilograms. 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 10,000 times as heavy as a Light Bulb
In other words, 420 kilograms is 12,000 times the weight of a Light Bulb, and the weight of a Light Bulb is 0.000083 times that amount.(a.k.a. lamp) (for A19-size, 60w, incandescent bulb by Bulbrite; package weight)
A standard, sixty-watt light bulb weighs about 0.034 kilograms. The tightly-coiled filament inside a bulb of this size would measure about 579mm if uncoiled and stretched out.
It's about 20,000 times as heavy as a Battery (AA)
In other words, 420 kilograms is 18,000 times the weight of a Battery (AA), and the weight of a Battery (AA) is 0.000056 times that amount.(Alkaline)
An "AA" size battery weighs 0.024 kilograms. 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 20,000 times as heavy as a Mouse
In other words, 420 kilograms is 20,000 times the weight of a Mouse, and the weight of a Mouse is 0.000050 times that amount.(a.k.a. "House mouse", Mus musculus) (adult)
The weight of a mouse is typically an average of 0.021 kilograms. 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 one-twenty-five-thousandth as heavy as The Eiffel Tower
In other words, 420 kilograms is 0.0000416 times the weight of The Eiffel Tower, and the weight of The Eiffel Tower is 24,000 times that amount.(a.k.a. La Tour Eiffel) (Paris, France) (total weight)
The Eiffel Tower weighs approximately 10,100,000 kilograms. Architected to be quickly assembled, the Tower contains only 930 cu. meters of solid material.