Abt helium balloon and electrolysis

AI Thread Summary
Helium balloons rise when they are positively buoyant, which depends on the amount of helium inside them; if they are tied together, they may not have enough lift to ascend. The discussion also highlights concerns about a glass cup designed with cathodes and anodes, where the interaction with water can lead to the deposition of potentially toxic substances on the bottom. This makes the cup unsuitable for drinking, as the layers formed could be harmful. Overall, the conversation emphasizes the principles of buoyancy in balloons and the chemical implications of electrolysis in the glass cup. Understanding these concepts is crucial for safety and functionality.
lwymarie
Messages
89
Reaction score
1
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 =)
 
Physics news on Phys.org
Can anyone ans me? ><
 
1. Not all balloons have enough helium to be positively buoyant.
2. No, I would not drink out of that cup.
 
russ_watters said:
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?
 
Thread 'Motional EMF in Faraday disc, co-rotating magnet axial mean flux'
So here is the motional EMF formula. Now I understand the standard Faraday paradox that an axis symmetric field source (like a speaker motor ring magnet) has a magnetic field that is frame invariant under rotation around axis of symmetry. The field is static whether you rotate the magnet or not. So far so good. What puzzles me is this , there is a term average magnetic flux or "azimuthal mean" , this term describes the average magnetic field through the area swept by the rotating Faraday...

Similar threads

Back
Top