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Physics library
Course: Physics library > Unit 18
Lesson 4: Discovery of batteries- Zinc copper cell (reduction-oxidation)
- How to measure?
- Battery meter (galvanometer)
- How Many Turns?
- Electrolyte test (pure water vs. vinegar)
- Reverse electrodes (polarity)
- Electrolyte (strong acid test)
- Electrolyte (salt test)
- Electrode (distance test)
- Electrolyte (temperature test)
- Electrode (surface area test)
- Standard cell
- How much electrolyte does a single cell need?
- The battery and electromagnetism
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Electrolyte test (pure water vs. vinegar)
First we attach our galvanometer to a piece of copper and zinc. Then we submerge the metals in pure water and vinegar. What is the difference? Why? Created by Brit Cruise.
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- Why isn't water an electrolyte? I know covalent compounds aren't supposed to be elctrolytes but what about polarity? Can't polar compounds be electrolytes?(6 votes)
- for being an electrolyte the first condition that comes is of electricity conductivity. as pure water is not conductive and does not have much free ions for conduction, it is not an electrolyte(1 vote)
- i have another question i did this in my back yard and i left for 3 minutes and there were flies in the vinegar and the my compass was lower when i left and whin i came back it was higher ?(2 votes)
- Could you use the "stop-bath" of silver based photography instead of vinegar for a stronger effect? They were interchangeable, "real stop-bath" would just last longer and stink less.(2 votes)
- what do you call that white circular metal?(1 vote)
- The white circular metal is I think a piece of zinc. I'm not sure(2 votes)
- can someone talk in the video and explain what's going on(1 vote)
- when we put the wire to water the compass does not move.....
when we put it in vinegar it moves.....
mainly because of the chemicals present in vinegar(2 votes)
- At, the needle on the compass moved when the two circles touched vinegar. However , I didn't really understand what happened. Can you explain it a little more so I can have a clear understanding. 1:13(1 vote)
- When the needle moves, that means there is a current (charge) that is moving between the copper and the zinc disks that are in the vinegar. Copper likes to gain electrons and zinc likes to lose them so the flow goes from the zinc to the copper. Remembering that current is defined in the opposite direction to the flow of electrons, the current is then flowing from the copper to the zinc. Vinegar has ions in it that are capable of transferring charge (It is an electrolyte - a solution with ions in it that can transfer a current through it). Pure water does not have ions in it to conduct the charge so the galvanometer needle doesn't move when the metals are dipped into the water.(2 votes)
- Why does the compass needle move at...What actually happens? Can u explain that? 1:13(1 vote)
- There is electricity flowing through the wire, causing an electromagnetic force.(2 votes)
- I highly doubt that penny is copper!(1 vote)
- Every penny is made out of copper. Go ask the US mint place where they made them(1 vote)
- Was this really pure, demineralised, water? It looks like mineral water is used in the video. Would this difference affect the outcome of the experiment?(1 vote)
- What did you get the zinc from?(1 vote)
- They came from an electrical casing. I am sure you can get zinc from other places too.(1 vote)
Video transcript
(clacking) (metal clattering) (coin clattering) (clicks) (water dripping) (liquid splashing)