You could put a flexible bladder (balloon) filled with helium in it.
The classic answer to this old question is: Fill it full of holes.
a balloon with helium.
A hole.
He puts a hole in it.Or helium?
An empty gas container actually weighs less than a full container.
Weights vary with airplanes (even those coming out of the same assembly line!) but the average is a little less than 1000 pounds (986 poounds).
The 2.5 hp & 3.5M Mercury both weighs 38 pounds. The 3.5 ML weighs 40 pounds.
Wait a couple of hundred years and put anti-gravity in it. Put air in it and take it on a ride on the vomit comet aircraft to have the barrel experence weightlessness. Maybe you could just take the top off and let it fill with the sorrounding air and it will weigh less while the top is off. BEST ANSWER: A HOLE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!11
An empty aluminum beer can weighs 15g. The tab weighs less than one gram. So in conclusion, 15g > less than 1g.
A horse
A hole
A hummingbird weighs less than a copper penny.
Because it weighs less than one that's full of product.
You could add a hole to the 50 pound barrel full of oil and drain out some of the oil to make it less than 50 pounds.