No.Sometimes farts are just gas so they do not always smell.
Usually it seems that they are. Some really are. Others are just not presented in a way that makes them visible. In short, some gases are visible and have colors. Check the link.
One of the best-known visible gases would be Chlorine. Chlorine shows as a putrid green-yellow cloud, and is incredibly toxic to humans.
they all contract.
halogens are much more reactive
yes they do
Excepting some colorless gases all chemical elements are visible.
Usually it seems that they are. Some really are. Others are just not presented in a way that makes them visible. In short, some gases are visible and have colors. Check the link.
Most gases are invisible to the naked eye. Gases are made up of molecules that are spread out and don't absorb or reflect light in a way that makes them visible. However, some gases do have odors that can be detected.
One of the best-known visible gases would be Chlorine. Chlorine shows as a putrid green-yellow cloud, and is incredibly toxic to humans.
the visible surface of the sun
No, not all gases are able to glow when an electric current is passed through them. Gases must contain certain atoms or molecules that can emit specific wavelengths of light when energized by the electric current in a process called fluorescence or phosphorescence in order to produce a visible glow.
Common gases in a house that may be visible include smoke (carbon particles), steam (water vapor), and possibly dust particles in the air. Other invisible gases like carbon dioxide, methane, and natural gas may also be present but not visible to the naked eye.
They are all visible to SOMEBODY.
The gasses that make up the sun's corona.
The corona.
all of them are because they are all gases
Greenhouse gases interact with visible light by allowing it to pass through the Earth's atmosphere. When sunlight reaches the Earth's surface, it is absorbed and then re-emitted as infrared radiation. Greenhouse gases trap some of this infrared radiation, preventing it from escaping back into space and leading to the warming of the Earth's surface.