1. Circuits & Batteries

2. Review …
Current electricity is the steady flow of electrons

3. An electric circuit is a continuous path along which electrons flow from one end of a battery to another. -

4. Electrons are negatively  charged, and are attracted to the positive end of a battery and repelled by the negative end.

5. So when the battery is hooked up to something that lets the electrons flow through it, they flow from negative to positive.

6. Electric circuits must always have at least:
● an energy source for electrons
● a conductor for electrons to travel through
● a load that converts electrical energy into a more useful form energy

7. A basic electric circuit

8. Add-ons to electric circuits:
● a switch allows you to safely stop or allow the flow of electricity

9. OFF open circuit, ON closed circuit
Which switch is ON?
OFF open circuit,
electrons cannot flow
ON closed circuit
electrons can flow

10. OPEN CIRCUIT
CLOSED CIRCUIT

11. Electrochemical Cells

12. An electrochemical cell is a device that converts chemical energy (from chemical reactions) into electrical energy

13. Parts of an Electrochemical Cells
A. Electrolyte - liquid that conducts electricity and where electrons are released
B. Negative Electrode – the end where newly charged electrons are collected and enters the circuit
C. Positive Electrode - the end where used electrons from the circuit are returned to the battery

14. Positive + Electrode
Negative - Electrode

15. DIY Electrochemical Cell
grapefruit
What is the kind of electrolyte used in this battery?
Grapefruit Juice (citric acid)

16. Which electrode gains electrons from the circuit?
DIY Electrochemical Cell
grapefruit
Which electrode gains electrons from the circuit?
Copper Electrode (+)

17. Which electrode loses electrons from the circuit?
DIY Electrochemical Cell
grapefruit
Which electrode loses electrons from the circuit?
Zinc Electrode (-)

18. Another DIY Electrochemical Cell

20. Battery Hacks

21. 2 Types of Electrochemical Cells
Wet Cells – contain an electrolyte liquid
Rechargeable
Ex: car batteries, phone batteries
Dry Cells – contains an electrolyte paste
Doesn’t leak as much, smaller, more portable
BUT the chemicals tend to get used up and charges can no longer be separated; non-rechargable
Ex: AA batteries, watch batteries

22. How Do Batteries Work?

23. Always recycle batteries as they contain toxic heavy metals such as nickel, cadmium, and lead
50% of all of the toxic metals in landfills comes from batteries!

24. Recycling Batteries Public Service Announcement

25. 1
Read pages pg 436 #1-5