1. Cells and Batteries

2. Electrical Cells and Batteries
An Electrochemical cell is a device that converts chemical energy into electrical energy.
A battery is a collection of cells

3. All Electrochemical Cells Contain 3 parts
positive electrode (cathode),
negative electrode (anode)
An electrolyte (chemical medium)

4. How Does a Cell Work?
Chemical reactions in the battery causes a build up of electrons at the negative terminal (anode).
This results in an electrical difference between the anode and the cathode. unstable build-up of the electrons.
The electrons repel each other and try to go to a place with fewer electrons (toward the cathode).
At the same time, electrons move away from the cathode, leaving it positive.

5. The electrons can’t flow through the electrolyte but can flow through the wire when the circuit is closed, lighting the light bulb along the way.

6. How does a cell work?
A cell is a source of electric potential energy – stored energy that has the potential to make something move or change.  
Because opposite charges attract each other, it takes energy to separate positive and negative charges. 
In a cell, chemical reactions separate the positive and negative charges. The chemical energy does the work.

7. What happens when you recharge a cell?
When you recharge a battery, you reverse the direction of the flow of electrons using another power source, such as solar panels. 
The electrochemical processes happen in reverse, and the anode and cathode are restored to their original state and can again provide full power.

8. How batteries work Ted Ed video

9. Two types of Cells:
Primary (Dry Cell)
Secondary (Wet Cell)

10. Primary Cell (Dry Cell)
Dry cell contains a moist paste as an electrolyte. 
Primary cell cannot be recharged because chemical reaction is irreversible. 

11. Secondary Cells (Wet Cell)
In a wet cell the electrodes sit in a liquid solution. 
Consists of an electrolyte solution, a zinc rod, and a copper rod, conductor, and a salt bridge. 

12. Secondary Cells (Wet Cell)
Secondary cell can be recharged using electrical energy to reverse the chemical reaction
Eg. Lead storage batteries (car battery) and
Eg. nickel – cadmium storage cell

13. Lemon Battery Explained: Sci Show

14. How to make a Lemon Battery

15. How to make a battery with spare change

16. Practice
CYU p305 # 8 – 12
Battery label WS