question of the day rules you must work alone you may use your textbook today you have 6 minutes...
TRANSCRIPT
Question of the Day Rules
You must work aloneYou may use your textbook
todayYou have 6 minutes to complete
the QOD
Good luck!!
Read page 176/177 of the textbook
1)Briefly explain how a wind turbine can generate electricity using wind energy.
2) Do you think it would be a good idea to build wind turbines in your region? Explain your answer, suggesting at least two advantages and two disadvantages.
Answer 1) Briefly explain how a wind turbine can generate electricity using wind energy.
ANSWER: The wind turns the blades of the turbine, which transforms mechanical energy into electrical energy.
2) Do you think it would be a good idea to build wind turbines in your region? Explain your answer, suggesting at least two advantages and two disadvantages.
Advantages: Once built, it is a clean energy source, wind is free
Disadvantages: The wind is unpredictable.– In the city, there is not enough space to build turbines.– In the country, the towers ruin the beauty of the landscape.
What are we doing Today?
Chapter 5QODNotes on Chapter 5Chapter 4 (EST) Test WednesdayVideo Project Classwork
Video Project
Due this Friday, December 19th, 2014 If you know you will not be there, you
should hand it in before that day to not lose marks
Make sure your video plays on a school computer before you submit it to me.
Make sure you and your partners names are on everything
Read through the rubric carefully for full marks
Electric Charge
All matter is made up of atoms
Atoms contain1. Protons (+)2. Neutrons (0)3. Electrons (-)
Law of Electric Charges
The law of electric charges states
that like charges repel, and
opposite charges attract.
Protons are positively charged and
electrons are negatively charged,
so they are attracted to each other.
Electric Force
The force between the charged objects is an electric force.
The size of the electric force depends on 2 things:1. The amount of charge (the greater the charge,
the greater the force)2. The distance between charges (the further the
distance, the less the force)
Electric Field
An electric field is the region around a charged object where electric forces can be exerted on another charged object.
(Repelled or attracted)
Charged Objects
Atoms do not have a charge because the number of electrons and protons cancel each other out.
Ex. 3 protons (+) & 3 electrons (-) = 0
Charged Objects
How do objects get charged? They either gain or lose electrons. Why not protons?Ex.3 protons (+) & 5 electrons (-) =
7 protons (+) & 2 electrons (-) =
Unit of Measurement
• The Elementary Charge is the charge carried by a single electron or proton. Its value is 1.602 x 10-19 C
• C is Coulomb. It is the measurement for electrical charge.
• 1 Coulomb = 6.25 x 1019 electrons or protons
How Can You Charge Objects?
There are 3 ways objects can be charged:1. Friction2. Conduction3. Induction
**In each of these, only the electrons move. The protons stay in the nucleus**
Friction
Charging by friction occurs when electrons are “wiped” from one object onto another.
Ex. If you use a cloth to rub a plastic ruler, electrons move from the cloth to the ruler. The ruler gains electrons and the cloth loses electrons.
The TriboElectric Series
When two different materials are pressed or rubbed together, the surface of one material will generally steal some electrons from the surface of the other material.
Triboelectric Series p.146 – Table 5.14
If you rub a glass rod against silk. Which of the substances gets a negative charge?
Silk acquires a negative charge
Glass acquires a positive charge
Conduction
Charging by conduction happens when electrons move
from one object to another through direct contact
(touching).
Ex. Suppose you touch an uncharged piece of metal with
a positively charged glass rod. Electrons from the metal
will move to the glass rod. The metal loses electrons
and becomes positively charged.
Induction Charging by induction happens when charges in
an uncharged object are rearranged without
direct contact with a charged object.
Ex.
If you charge up a balloon through friction and
place the balloon near pieces of paper, the charges
of the paper will be rearranged and the paper will
be attracted to the balloon.
Induction: The production of a charge in an uncharged body by bringing a charged object close to it
When negatively charged rod is put near a metal can...
electrons of the can are pushed away from the rod.
top of the can: positive
& attraction > repulsion
+++ +
+
metal can
- --
--
----- --
buttom of the can: negative
induced charges attraction
repulsion
Conservation of Charge When you charge something by any
method, no charges are created or destroyed.
The numbers of electrons and protons stay the same. Electrons simply move from one atom to another.
Conductors and Insulators
An electrical conductor is a material in which charges can move easily.
Most metals are good conductors because some of their electrons are free to move.
Conductors are used to make wires. For example, a lamp cord has metal wire and metal prongs.
Conductors and Insulators
An electrical insulator is a material in which charges cannot move easily.
Insulators do not conduct charges very well because their electrons cannot flow freely.
The insulating material in a lamp cord stops charges from leaving the wire and protects you from electric shock.
Plastic, rubber, glass, wood, and air are good insulators.
Static Electricity
Static electricity is the electric charge at rest on an object.
When something is static, it is not moving.
Electric Discharge The loss of static electricity as charges
move off an object is called electric discharge.