Download Science 9 - Unit D - Lesson 2

Science 9
Sections 1.1 – 1.3
Unit D: Electrical Principles and Technologies
84 mins
Electrical Energy
Energy that is generated from the movement of
electrons.
Static Electricity
The imbalance of electrons in or around an object.
This remains until a current or electrical discharge
rebalances the charges.
Draw
Examples: Lightning
Electrical Charge and Attraction
Neutral (No Attraction)
Draw
Like Charges (Repel)
Unlike Charges (Attact)
LAWS of Electrical Charge
- Opposite Charges attract each other
- Like charges repel each other
Electrical Discharge
Excess charge can “jump” to another object, felt as a
shock or spark… or a lightning bolt.
Van de Graaff Generators
Mechanically build up static charge.
Check and Reflect Questions: 1-9
Not Notes pg. 279
Electric Eel (Fish).. not an eel
Current Electricity
The steady movement of electrons through an
object.
Requires a complete circuit for the electrons to
flow.
Circuit – complete path that charged particles flow
through
Parts to a Circuit
1) Power source (Cell or Generator)
2) Path for the current to flow (Wires)
3) Load (Something to do work, Bulb)
Make a circuit Lab
1 wire, 1 cell, 1 bulb
Draw an example from the class
Characteristics of Electricity
1) Amperes (Amp = A)
The rate at with current flows
2) Voltage (Volt = V)
3) Power (Watt = W)
Formula
Power (P) = Voltage (V) x Amperes (I)
Dangers of Electricity
Short Circuit (Downed Power line)
Electrical Shock
Protecting yourself from Electrical Shock
-
Use insulators to block the flow of electricity
The amount of energy in a single charged particle
The Voltage x Amperes, Amount of energy per
second used
P = VxI
A bypass of the normal circuit, path of least
resistance
High Voltage is dangerous (50000 V can kill)
Amperage is more dangerous:
- 0.015 A can cause muscle contraction
- 0.1 A can kill…
Wood, Rubber, and air don’t allow current to flow
easily, they are known as insulators
Break into groups and each group MUST place an
example on the board.
-
Always unplug a device before serving
-
Don’t use damaged cords/devices
-
Don’t bypass safety features
-
Don’t remove the third prong
Plugs, Fuses, and Breakers
Plugs
- have grounds
Electricity has another path to travel
Fuses
- Break the circuit to stop the flow of electricity
Must be replaced, the fuse melts (burned out)
Breakers
- Flip off like a light switch to stop the flow of
electricity
Lightning
A wire heats up and flips a mechanical switch that
flips off the breaker
NEVER turn a break back on until you’ve fixed the
problem