Why did the needle seem to be shaking kinda rapidly once he tapped it?

any gauge with a needle will shake if you tap it with some really cheap ones the needle will get caught on the top.

Is the spacing between metals necessary? Since deflection decreases with increased distance, why not just touch the two coins together?

I assume that the electrolyte has some resistance, so that's why current increases with decreased distance: less electrolyte resistance to get in the way. If the two coins touched, would there be current loops between the coins, since this would be the path of least resistance? This is a fantastic series of videos, by the way!

was that slat he put on the spoon why

Yes, that was salt on the spoon. In the 'Electrolyte (salt test)' video you will see that adding salt to the vinegar makes it a better conductor. https://www.khanacademy.org/science/discoveries-projects/discoveries/batteries/v/electrolyte--salt-test

Would not the hot liquid melt the rubber band?

It depends on the quality of the rubber, so in some cases yes and in others no.

Can we use anything besides coins?

Sure! try any metals you can find around the house!

Main content

Standard cell

Name: Standard cell
Uploaded: 2013-04-20T15:47:37Z
Description: Testing out a cell which holds the metals at a constant distance. We add it to salt water and then check the deflection. Can this be used as a standard unit?

Google Classroom

Testing out a cell which holds the metals at a constant distance. We add it to salt water and then check the deflection. Can this be used as a standard unit? Created by Brit Cruise.

Want to join the conversation?

Sort by:

Christian
Posted 11 years ago. Direct link to Christian's post “Why did the needle seem t...”
Why did the needle seem to be shaking kinda rapidly once he tapped it?
Button navigates to signup pageComment on Christian's post “Why did the needle seem t...”
(8 votes)
Answer
- Carmel01
  Posted 9 years ago. Direct link to Carmel01's post “any gauge with a needle w...”
  any gauge with a needle will shake if you tap it with some really cheap ones the needle will get caught on the top.
  Button navigates to signup page
  (2 votes)
Michœl
Posted 10 years ago. Direct link to Michœl's post “Is the spacing between me...”
Is the spacing between metals necessary? Since deflection decreases with increased distance, why not just touch the two coins together?
Button navigates to signup pageButton navigates to signup page
(6 votes)
Answer
- Michœl
  Posted 10 years ago. Direct link to Michœl's post “I assume that the electro...”
  I assume that the electrolyte has some resistance, so that's why current increases with decreased distance: less electrolyte resistance to get in the way. If the two coins touched, would there be current loops between the coins, since this would be the path of least resistance?
  
  This is a fantastic series of videos, by the way!
  Comment on Michœl's post “I assume that the electro...”
  (8 votes)
Tiny tim
Posted 10 years ago. Direct link to Tiny tim's post “Is the brown thing in 0:0...”
Is the brown thing in
0:08
cardboard?
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
EvansTreasure 2025
Posted 10 years ago. Direct link to EvansTreasure 2025's post “was that slat he put on t...”
was that slat he put on the spoon why
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
- Flanny
  Posted 10 years ago. Direct link to Flanny's post “Yes, that was salt on the...”
  Yes, that was salt on the spoon. In the 'Electrolyte (salt test)' video you will see that adding salt to the vinegar makes it a better conductor.
  https://www.khanacademy.org/science/discoveries-projects/discoveries/batteries/v/electrolyte--salt-test
  Button navigates to signup page
  (2 votes)
MarushiaDark
Posted 10 years ago. Direct link to MarushiaDark's post “So the ideal battery woul...”
So the ideal battery would be one that has discs of large surface area close to one another dipped in a strong, hot, salty acid?
Button navigates to signup pageComment on MarushiaDark's post “So the ideal battery woul...”
(2 votes)
Answer
Ok Boomer
Posted 9 years ago. Direct link to Ok Boomer's post “What would happen if you ...”
What would happen if you did the same thing, except much larger? Would it be able to power a house?
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
я̿€̿ρ̿Ł̿ɪ̿т̿Ǻ̿ƶ̿
Posted 9 years ago. Direct link to я̿€̿ρ̿Ł̿ɪ̿т̿Ǻ̿ƶ̿'s post “I think the author needs ...”
I think the author needs to talk to clarify any questions that we might have. Any answers to what a standard cell really is?
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
Peculate
Posted 10 years ago. Direct link to Peculate's post “Would not the hot liquid ...”
Would not the hot liquid melt the rubber band?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
- Jonathan Ziesmer
  Posted 10 years ago. Direct link to Jonathan Ziesmer's post “It depends on the quality...”
  It depends on the quality of the rubber, so in some cases yes and in others no.
  Button navigates to signup page
  (2 votes)
BoMAN
Posted 10 years ago. Direct link to BoMAN's post “Can we use anything besid...”
Can we use anything besides coins?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer
- brit cruise
  Posted 10 years ago. Direct link to brit cruise's post “Sure! try any metals you ...”
  Sure! try any metals you can find around the house!
  Button navigates to signup page
  (2 votes)
Ghazanfer Ali
Posted 10 years ago. Direct link to Ghazanfer Ali's post “in standard pencil cells ...”
in standard pencil cells , what is used as elecyrolyte?
Button navigates to signup pageButton navigates to signup page
(1 vote)
Answer