air, nitrogen, oxygen, trace gases, and sometimes helium
You can buy scuba tanks at the internet page "DiversDirect" or in a special diver store. Or you buy on Ebay a used scuba tank, its cheaper but the scuba tank could be defect or something else.
SCUBA tanks are metal (usually steel or aluminum) that are filled with compressed air. This is loosely related to a pneumatic system.
Scuba tanks need to be visually inspected and need a hydrostatic test done every five years.
Generally compressed air (oxygen 20 % and nitrogen 80 %; for other mixtures see the link bellow.
Naturally the air we breath has 70% of nitrogen and only 21% of oxygen, this is done is scuba diving as well. Just oxygen is not enough for living, while oxygen is essential one.
The air inside SCUBA tanks is, usually, just regular air that has been compressed and "jammed" into a tank. Some diving applications utilize gas mixtures of oxygen, nitrogen (and sometimes hydrogen).
Hide behind those water tanks. The scuba tanks are filled and ready to go.
They are made usually from Aluminium or steel
Used scuba tanks can be found on eBay, but for new equipment, there are brick and mortar "dive shops" that sell tanks and other diving accoutrements. Scuba tanks can be found online at Amazon, and at other online portals that specialize in diving equipment such as LeisurePro.
No, they cannot.
Scuba divers also wear lead weights on a belt
For normal "sport" diving, scuba tanks are filled with just plain old air! That's just the mix of gases you're likely breathing right now, and it contains 78% Nitrogen, 21% Oxygen, and 1% other gases. But nitrogen can cause problems for divers ("bends" and "narcosis"). So for technical diving (below 100 feet), divers sometimes use Nitrox, less nitrogen than normal air, and more oxygen. But even pure oxygen can be dangerous when breathed under pressure. In fact, breathing pure oxygen while scuba diving below 25 feet can be fatal! So for very deep technical dives, the inert gas helium is often added into the gas mix; which can be heliox (oxygen & helium), or trimix (oxygen, helium, and nitrogen).
Yes, they require High pressure air (nitrogen) tanks. They cannot run off of CO2.
they have weight belts
it doesn't affect the tank
normal gas for scuba is 20% oxygen, 80% nitrogen. You can take a nitrox course, in which you are then qualified to use different blends of oxygen and nitrogen. i.e. 40% oxygen and 60% nitrogen
Most SCUBA divers dive with compressed air, which is normal atmospheric air compressed into a scuba tank.
Most scuba tanks are filled with simple purified air. However, some are filled with oxygen enriched air called 'nitrox' or (less commonly) a blend of helium, oxygen and nitrogen called 'trimix' or (even less commonly) helitrox or heliox.
A cardinal rule for scuba diving tanks is to never completely empty your scuba diving tank. When planning your scuba dives, it is important that you consider to complete your dive with enough air left within your scuba diving tank.
I would think so, because there are two of them mixed together. Air in a scuba tank or anywhere else should be heterogeneous. A scuba tank filled with either oxygen or nitrogen would be homogeneous.
By oxygen tanks - similar to SCUBA divers.