Abt helium balloon and electrolysis

[lwymarie]

Sorry I am poor at using English to describe things. I hope you will patiently read my questions and answer them.


1. I saw some helium balloons today. We all know that if you do not hold the helium balloons, they will rise up to the sky. But today I saw a bundle of helium balloons (their holding strings are tied up together) on the floor. They do not rise up to the sky. Instead, the balloons just jump up and down or move horizontally. Can you explain why is it so? When do the helium balloons rise up and when do they not?

2. I bought some funny glass cups. There are the cathode and the anode at the inner surface of the bottom of the cup. The bottom of the cup contains some light bulbs. So when you pour some water into the cup, the bottom of will light up.
So if water inside the cup is replaced consistently, there will be a thin layer (originally cations) covering the cathode. In the same way, there will be a thin layer (originally anions) covering the anode. So the cup will become 'toxic' as substances are deposited at the bottom. So these cups cannot be used for drinking. Am I right?


Thank you =)

 

[lwymarie]

Can anyone ans me? ><

 

[russ_watters]

1. Not all balloons have enough helium to be positively buoyant.
2. No, I would not drink out of that cup.

 

[lwymarie]

1. Not all balloons have enough helium to be positively buoyant.
2. No, I would not drink out of that cup.

So toxic materials may be deposited at the bottom?