To my knowledge helium is the only practical lift element for blimps. Hydrogen actually works better than helium, and it is cheaper, but it is highly combustible and not used anymore.
Hydrogen is not used in blimps any longer because it is flammable and dangerous (see: Hindenberg)
Yes, helium has been used in blimps as a lifting gas. Helium is less dense than air, which allows it to provide buoyancy and help the blimps stay afloat. However, today, most blimps use a combination of helium for lift and air for control and propulsion.
Today's blimps are not filled with flammable hydrogen gas like Hindenburg was, but normally the non-flammable helium.
Blimps began to be used commonly during World War I, and are still in use today.
Bitties law
Are now known as blimps, they are more used for advertising purposes.
Yes, this is the basic principle of blimps and balloons.
They are filled with helium gas. They used to be filled with hydrogen gas but that proved to be deadly at times.
Size and type of gas contained in the envelope.
Goodyear is well known for its blimps. In order for these blimps to float, they contain a lighter than air gas. Hydrogen is to dangerous for this purpose, so helium is used. Thus, helium is the noble gas used by Goodyear.
Helium has a low density and causes balloons and blimps to float
Blimps are obsolete nowadays. Blimps were always a danger to air travel, as well as its passengers. An example of the dangers of blimps was the Hindenburg tragedy.