You have to first obtain a helium tank and then affix the balloon to the nozzle of the tank and turn on the valve, releasing the compressed helium into the container ie. Balloon. But do not leave the...
It's all mass and weight. Air will rise in water, because it is lighter.(Hence bubbles.) Helium on the other hand is lighter than air, so it too will rise when 'submerged' in it. It doesn't have...