Because if you try to dive to the bottom of the ocean without an oxygen cylinder, you would have to surface again before you even get all the way down. Furthermore if you did manage to get to the bottom you would have to swim back to the surface for air and if you cant get to the surface in time you could very well drown by water filling up your lungs.
if you're talking about the big cylinders they carry on their backs, then that is their main supply of oxygen. if you're talking about smaller ones that are usually strapped around their waists or attached to their "backpacks", then those are in case a fellow diver runs out of oxygen and they need a small amount of emergency oxygen or you yourself run out and need something to help you until you return to the surface again.
You can buy a diving regulator online at Divers Supply, Leisure Pro, Dive Right, and House of Scuba. You can also purchase a diving regulator on eBay and Amazon.
They can't survive without oxygen but they can survive with an oxygen mask that scuba divers use and with supply of oxygen of course .
With scuba diving, you are diving with an oxygen tank on your back and a regulator in your mouth. For SNUBA, there isn't an oxygen pack on your back, instead your oxygen supply is a long hose attached to a raft on the surface of the water.
Spacecraft need an internal oxygen supply to provide a breathable atmosphere for astronauts during space travel. Since there is no oxygen in space, spacecraft must carry their own supply to support human life. This ensures that astronauts have the necessary oxygen to breathe and carry out their activities while in space.
You can buy diving gloves at most underwater sports stores. There are many on the web such as Leisure pro or Divers Supply. It's worth also checking out the usual suspects like Amazon and eBay.
A space shuttle carries its own supply of oxygen to sustain the astronauts' breathing when they are in space where there is no atmosphere. It ensures they have a continuous source of oxygen for respiration during the mission.
Astronauts have oxygen to breathe in the spaceship because the spacecraft is equipped with life support systems that generate oxygen through a process called electrolysis, which splits water molecules into oxygen and hydrogen. Additionally, spaceships often carry tanks of compressed oxygen as a backup supply.
They make their own oxygen by mixing nitrogen with carbon dioxide.
Without oxygen, astronauts would not be able to breathe and would suffer from hypoxia, which can lead to unconsciousness and eventually death. The lack of oxygen in space can also cause damage to the brain and other vital organs. Special equipment, like space suits and spacecraft, are designed to provide astronauts with a controlled environment that includes a supply of oxygen to prevent these issues.
Astronauts wear spacesuits that are equipped with a life support system, which includes an oxygen supply for breathing. This system provides them with a controlled environment to breathe while they are in the vacuum of space.
Astronauts wear helmets or space suits, not hats, to provide protection in space from extreme temperatures, micrometeoroids, and radiation. The helmet also ensures they have a stable supply of oxygen and communication.
Astronauts breathe using the life support systems on their spacecraft or spacesuits. These systems provide a controlled supply of oxygen for them to breathe while in space. Inside the spacecraft, the air is managed to ensure astronauts have a safe and breathable atmosphere.