Grade 9 Science
Unit 3 Booklet: Characteristics of Electricity
Name: ______
Chapter 7:
Static Charge Is Produced
By Electron Transfer
Static Electricity
· Refers to that can be collected and held in place.
· It is the temporary transfer of ______.
· Protons have a ______charge
· Electrons have a ______charge
· When the number of protons equals the number of electrons, the atom is ______.
· If electrons are ______from a neutral object, the object will become positively charged.
· If electrons are ______to a neutral object, the object will become negatively charged
Visualizing Charge Transfer
Fill in the diagram below.
Charged Negative
Neutral
Charged Positive
Electric Discharge
· The removal of ______from an object.
Ex: Lightning and shocks
The Coulomb (C)
· The ______of electric charge.
· It takes the addition or removal of ______electrons to produce 1C of charge
· This is about the number of electrons that pass into a 100 W light bulb per second.
Laws of Electric Charges
1.
2.
3.
Chapter 8:
Ohm’s Law Describes the Relationship of Current, Voltage and Resistance
Electric Potential Energy and Voltage
· Electric Potential Energy is ______electrical energy
o An example of this is a ______
· The change in potential energy per coulomb of charge describes
______, which is also called ______
Current Electricity
· Electric Charge describes a ______up of charges at the negative terminal of a cell/battery which then flows from this terminal as ______charges repel one another
Draw arrows on the circuit below to show which way the electrons are travelling:
Electric Circuit
· A complete pathway that allows ______to flow.
· Will transform ______energy into other forms of energy.
Label the parts in the following circuit:
(load, conductor, source, switch)
Electric Current
· The amount of ______passing a given point in a conductor per second.
· Measured in ______(A)
· Measured using an ammeter
Current Electricity
· The continuous flow of charge in a complete ______
Resistors
· Used to control ______or potential difference in a circuit.
Draw a Circuit Diagram of a 2-celled battery, an open switch, a resistor, a bulb and an ammeter. Include a voltmeter to measure the potential difference across the resistor.
Ohm’s Law
· The mathematical relationship comparing ______(V), ______(I) and ______(R)
Fill in the triangle to describe the relationship between V, I, and R
Sample Problem: Calculate the current in a circuit containing a 220 ohm resistor with a 15 V power supply.
Chapter 9:
Circuits are Designed to Control the
Transfer of Electrical Energy
Series Circuits
· There is only ______for the current to travel.
· Bulbs connected in series; when one goes out they ______go out.
· As you add more bulbs, the brightness of the bulbs ______.
· Adding more bulbs increases the ______thereby decreasing the total ______in the circuit.
· An example of a series circuit would be ______.
Parallel Circuits
· A circuit with several ______paths.
· Bulbs connected in parallel; when one goes out, the others are ______.
· As you add more bulbs, the brightness is ______.
· Resistance ______increase.
· No current is created or destroyed only ______.
· Adding resistors in parallel will decrease the total resistance. This will ______the total current leaving the battery.
Series Circuit / Parallel Circuit# of Pathways
Effect of removing
a load
Voltage Drop
Current
Resistance
Connecting cell
to form a battery
Circuit Breakers
· Act as a ______that can cut off all power coming in to your house.
Fuses
· Contains a metallic ______that melts when excessive current heats it up.
Grounding Terminals
· Allows excess ______to flow in to the ______instead of giving you a shock.
Electrical Energy
· The ability to do ______
· Measured in Joules (J)
Electrical Power
· The ______in electrical energy.
· The rate at which work is done or energy is transformed.
· Measured in ______(W).
Electrical Energy Costs
Depend on 3 factors:
1. ______
2. ______
3. ______
Power Rating
· A measurement of how much ______an electrical device ______for every second it is in use.
Calculating Energy Consumption
Fill in the correct letters in the triangle below.
NOTE:
E = energy transferred (J)
P = power (W)
t = time (s)
Sample Problem:
How much energy is being used to run a 1500w hairdryer for 3 minutes?
Electrical energy may be converted to other forms such as:
1.
2.
3.
%Efficiency = Energy Output/Energy Input X 100%
Sample Problem: A toaster uses 15000 J of energy to generate 7600 J of heat. How efficient is it?
· Details how much ______an appliance uses in a year and compares to other appliances.
Reducing Electrical Consumption
· Improve ______of home
· Turn off lights when not in use
· Use energy ______light bulbs
· Air dry clothes when possible
Energy Generators
Electrical generator (made up of a coil of wire and a ______).
Electrical Generating Stations (P. 327)
Alternate Energy Sources
1.
2.
3.
Constraints to New Technology (Pg. 330- 334)
1.
2.
3.