Thursday 31 October 2013

Oct. 31 – Energy Presentations Continued

Here are more links to download other people's presentations:

Period 1


Period 4

Last few presentations tomorrow then we move onto talk about electric circuits.

Homework:

Complete the previous handout,

Wednesday 30 October 2013

Oct. 30 – Energy Presentations

Today was presentation day!

Remember, questions about any of these energy sources can show up on the test.  You must understand all the sources, even if you did not research it yourself.  I hope you all paid attention!

Here are copies of people's presentations to help you review.

Period 1


Period 4

Homework

  • If you presented today, begin working on the handout from yesterday.
  • If you have not presented yet, continue preparing.

Tuesday 29 October 2013

Oct. 29 – Electricity Cost and Efficiency

Learning Goals: Understand how to describe the efficiency of a device.

Success Criteria: Be able to calculate the % efficiency of different devices.

I did a few quick examples today and then we spent the rest of the period preparing for the presentations.  Here are the definitions and examples.

Cost of Electricity

In Ontario, the price of electricity varies depending on the time of day.  Here's a summary on this website: http://www.ontarioenergyboard.ca/OEB/Consumers/Electricity/Electricity+Prices




To calculate the total cost, you use on of the following two methods.

Cost = E x Price
Cost = P x t x Price

Example: How much does Ari's fridge cost to run per year?  The enerGuide label reads 772 kWh per year.  The price of electricity is 10.4 cents/kWh.

Given: E = 772 kWh per year
Required: How much is the cost per year?
Analysis: Cost = E x Price 
Solve:
Cost = 772 kWh x 10.4 cents/kWh
        = 8028.8 cents
        = $80.29
Statement: The cost is $80.29 per year.

Example:  Ashley's TV uses 45 W.  How much does it cost her to watch TV for 4 hours during mid-peak time (10.4 cents/kWh).

Given: P = 45 W = 0.045 kW, t = 4 hours
Required: How much is the cost for the four hours?
Analysis: Cost = P x t x Price 
Solve:
Cost = P x t x price
        = 0.045 kW x 4 h x 10.4 cents/kWh
        = 1.872 cents
Statement: The cost for 4 hours of TV is about 2 cents.

Efficiency

How well the energy is used.

All electrical devices require electrical energy.
All of them do some kind of work as output.

Efficency = (energy out ÷ energy in) x 100%



Example: 

An incandescent light bulb uses 100 J of electric energy and produces 2 J of light energy.  Calculate the efficiency.

efficiency = (E out / E in) x 100%
                = (2 J / 100 J) x 100%
                = 2 %

A compact fluorescent bulb uses 20 J of electric energy for the same amount of light.  Calculate its efficiency.

efficiency = (E out / E in) x 100%
                = (2 J / 20 J) x 100%
                = 10 %

We can see that the compact fluorescent is much more efficient.  It is impossible to have 100% efficiency!



You should now be able to do all the questions on this handout: 

Homework:


  • Prepare and Practice your presentations!
    • If you're using PowerPoint, send me a copy.
    • If you're using Prezi, use the "share" button to send me a link.


Monday 28 October 2013

Oct. 28 – Energy and Power

Energy and Power

Learning Goals: Understand how to calculate power and energy used for different devices.

Success Criteria: You can successfully solve word problems involving power.

Today I discussed how we measure energy using Joules (J).  One Joule is not a lot of energy.  It takes about 1 J to lift your textbook 10 cm.

Normally we use kilojoules: 1 kJ = 1000 J.

Household devices use even more energy, so we use kWh (kilowatt hours):

  • 1 kWh = 3 600 kJ = 3 600 000 J



This label can be found on the freezer above.  It uses 512 kWh every year to operate this freezer.

Homework: Find one of these Energuide labels at home.  Look on appliances such as fridge, stove or washer/dryers.  Bring back the following tomorrow,

Appliance: (fridge, stove, washer/dryer, etc.)
Brand: (Maytag, GE, LG, etc...)
kWh per year: ###

Warning: don't try to move your fridge or stove to look for the label!  If you can't find it, look on another appliance.  Stay safe!

Power

Power refers to how fast energy is used.  It is measured in units of Joules per second or Watts.
  • 1 J/s = 1 W
To calculate power, we use the equation:

Where
  • P = power (Watts)
  • E = energy (Joules)
  • t = time (seconds)
Example: Usain Bolt uses 15 kJ of energy to run 100 m in 9.58 s.  How much power does he use?



Given: E = 15 kJ, t = 9.58 s, distance = 100 m

Required: How much power, P?

Analyze: P = E / t

Solve: P = 15 kJ / 9.58 s
           P = 1.57 kJ/s
           P = 1.57 kW

Statement: Usain Bolt uses 1.57 kW of power to run 100 m.

Example: a mantis shrimp punches with 15 J of energy in 2.7 ms.  How much power does the mantis shrimp use to punch?



And some Vidoes!  



G: E = 15 J, t = 2.7 ms = 0.0027 s
R: How much power, P?
A: P = E/t
S: P = 15 J / 0.0027 s
    P = 5555.5555555 W
    P = 5600 W
    P = 5.6 kW
S: The shrimp uses 5.6 kW to punch.  Five times more powerful than Usain Bolt!

Example: How much energy does a  60 W light bulb use in 1 hour?

G: P = 60 W, t = 1 hour = 3600 s
R: How much energy?
A: E = P t
S: E = 60 W x 3600 s
     E = 216000 J
     E = 216 kJ
S: The light bulb uses 216 kJ in one hour.

Handout with more practice: Power and Efficiency Problems

Homework:
  • Find the Energuide labels
  • Work on your presentation.


Friday 25 October 2013

Oct. 25 – Research Period

Congratulations on completing your quiz yesterday!

Here's the next project: Energy Project

In partners or alone, you will research one form of energy production and present it to the class.

  • Geothermal
  • Biomass
  • Tidal
  • Wind
  • Fossil Fuels
  • Solar
  • Hydroelectric
  • Nuclear
Presentations should be 5 minutes long and answer all the questions in the handout.  You can make your presentations in any format.

Today we spent all day on planning and research.  Here's are the deadlines:

Monday, Oct. 28 – Research Notes Due
Wednesday, Oct. 30 – Presentations Begin

Homework: Finish research and begin planning your presentations over the weekend.

Do not expect more class time to work on it!

Wednesday 23 October 2013

Oct. 23 – Electric Cells and AC/DC

Quiz Tomorrow!  Here's what to expect.

Knowledge Questions:

  • Multiple choice and fill in the blanks.
  • These questions involve basics such as Law of Electric Charges, charging, conductors, insulators, etc.
Communication Questions:
Thinking/Inquiry:
  • Long Answer.
  • I will ask you how to do something in a laboratory and you describe the procedures.
Good luck!

Here's today's materials.

Continue with Electric Cells


Parts of an electric cell:
 - positive terminal (cathode)
 - electrolyte
 - negative terminal (anode)

Electrons move from the anode to the cathode.



Create your own electric cell with a lemon!  Here's how:  http://hilaroad.com/camp/projects/lemon/lemon_battery.html

Then we watched this video of charging an iPhone with a watermelon and discussed why it was fake:



Fuel Cells

Electric cells that can operate continuously by adding fuel.
Ex: Hydrogen fuel cells in cars.  They us hydrogen to produce energy and power the car.


Advantages :)
Disadvantages :(
- when you burn hydrogen, the waste is water
- no greenhouse gases
- don’t have to dig up more fossil fuels
 - people will not give up gasoline
 - hard to find hydrogen on Earth
 - highly reactive
 - need to use a lot of energy to get pure hydrogen

Then we went on to discuss different forms of current electricity.

Forms of Current Electricity 

Learning Goals: Understand the difference between AC and DC electricity.

Success Criteria: You can describe the difference between AC and DC electricity.


We then talked about the fact that there are two different kinds of electricity.  DC goes in one direction all the way around the circuit, while AC goes back and forth.  Both are able to carry energy and both are usefully in different ways.

FUN FACT: The band AC/DC got their name from an "alternating current/direct current" label on a sewing machine!

Then we talked about how electricity is generated.  In nature, there's an animal that can generate it's own electric field.  Have a look at this video: http://www.youtube.com/watch?v=y9wktSQdyaE

We needs more than eels to general electricity for entire cities though, so we use electric generating stations that turn other forms of energy into electric energy.




Have a read at chapter 12.4 to complete the handout.

Homework: Study for Quiz

Tuesday 22 October 2013

Oct. 22 – Currents and Circuits

Current Electricity and Circuits

Learning Goals: Understand how current flows through a circuit.

Success Criteria: You can describe the different parts of a circuit and recognize whether it is open or closed.

I'm madly marking away at your element assignments so please forgive me for a shorter blog post today.  Here are the handouts:



A common circuit with wires, battery, switch and bulb.
Keep in mind a circuit is like a roller coaster:
A circuit is like a roller coaster.  A chain (battery) starts the roller coaster (electrons) moving and they go all the way around the track (wires). 


Homework: Questions listed at the bottom of the handouts.

Monday 21 October 2013

Oct. 21 – Discharges

Reminder: there is a quiz on Thursday, Oct. 24!  It will cover all of chapter 11.  Here are the quiz topics:

Handout: Chapter 11 Quiz Topics

Discharges

Learning Goals: Understand how electrical discharges occur.

Success Criteria: You can describe examples of electrical discharges and explain how they occur.

This is the final topic from this week that will be on the quiz: discharges.  When a lot of charges build up, they can jump from one object to another.

Discharges: The rapid transfer of electrons from one object to another.

Examples: being shocked by a doorknob, lightning, tasers, unplugging outlets.





Here are some amazing photos of lightning storms:

Do you think lightning moves up from the Earth to the clouds or down from the clouds to the Earth? The answer is a little of both.  Sometimes lightning even goes from clouds to clouds.

Here are some videos of electric discharges.
WARNING: All of these are incredible dangerous situations!  Always be cautious around electrical power sources.

The movie "Like Mike" makes it look like you get magical powers from being shocked.  In real life, you would probably die.  Again, I repeat, be extremely cautious around electrical power sources!

Next we worked on some questions regarding electrostatic applications.  These questions will help prepare you for the quiz.


Homework: Complete the handout.

Friday 18 October 2013

Oct. 18 – Conductors and Insulators

A lot of people seem to have trouble completing the lab yesterday so I have offered an extension!  You may hand in the lab on Monday without penalty.  Make sure you take the time to complete it well.

I also announced that there will be a QUIZ on Thursday, Oct. 24.

I handed out a couple of worksheets to give you more practice for the quiz.

Handouts: 

Here are some solutions for the electrostatic activity:

Electrons have moved from the acetate rod onto the cotton cloth.

Electrons have moved from the electroscope into the rod.  The electroscope has an overall positive charge and the leaves repel.
I also went over a question from the homework on Tuesday.  Page 477 #6.


#6. Describe how electrons move when a positively charged object is grounded.

When a positively charged object is grounded, electrons move from the ground into the object.  The object is then neutral.


Next we started a new topic:

Conductors and Insulators

Learning Goals: Understand the difference between conductors and insulators.

Success Criteria: You can identify a material as a conductor or insulator.  You can describe some applications of conductors and insulators.

Here are the definitions:
  • Conductors:  materials that allow the movement of electrons.
  • Insulators: materials that inhibit the movement of electrons.

Section: 11.4, P. 480, list of common conductors and insulators.




All wires use a collection of conductors (copper) and insulators (plastic) to allow electricity to move and to protect people from being shocked.


Power lines use a combination of conductors and insulators to carry electricity to houses and to avoid losing it into the ground.


Here's a video on how laser printers work.  More details can be found in your textbook on page 481-482.

Homework: Complete the Lab and worksheets.

Thursday 17 October 2013

Oct. 17 – Charging Objects Lab

Today we worked on this laboratory activity:

Handout: Charging Objects Lab

I hope everyone was able to get all the observations for each of the three sections.  The lab is due tomorrow, so please answer all the questions at home and hand it in tomorrow.  You might have to search online to find information for the Application questions.

"But my observation is wrong!"

As you are working on the answers, you might notice that your observations don't always match what you might have expected.  This is perfectly normal in any experiment.  It is important to write down exactly what you observed rather than what you expect to see.  If you see something you don't expect, make a note of it.  Try to think of all the ways that this discrepancy might have occurred.  This is the best way to learn and the only way new discoveries are made!


Wednesday 16 October 2013

Oct. 16 – Charging by Induction and Activities

Today we got a chance to try to charge different materials and see what happens.

Handout: Investigating Charges

This activity should prepare you for the lab tomorrow which will involve charging different materials.  I hope that through today's activities you got a sense of how difficult it is to charge objects and how much care you need to take to ensure that your experiments work well.

You also got your Chemistry Unit Test back.  Please let me know if you have any concerns with your mark!

I then talked about induction and how it works.  here are some brief notes:

Induction

Learning Goals: Understand how to charge without contact.

Success Criterial: You can complete the laboratory investigation tomorrow.

Induction is charging an object without contact.

Temporary:
 - A charged object is brought near a neutral object.
 - Charges separate in the neutral object.



Permanent:
 - A charged object is brought near a neutral object.
 - Charges separate in the neutral object.
 - Ground the neutral object.
 - Disconnect the object from the ground.

Details from your textbook:


Homework:

Prepare for your lab by reading the following section:

  • Read 11.6, P 486-487

Tuesday 15 October 2013

Oct. 15 – Charging by Contact

Welcome back to class!  I hope everyone had a good long weekend.
We started with a bit of review to see if you remember what we did last week.  You should be able to identify what happens to charged objects and how they will behave.

Will these two objects attract, repel or not move at all?


Answer: The electrons (– charge) will move to one side and the overall result is that they will attract!

Charges can sometimes move around inside a neutral object and overall the two objects will attract.
Today we asked the question: How do objects become charged?

Learning Goals: Understand how objects gain or loose charge.

Success Criteria: You can identify how an object will be charged after contact or friction with another object.

How do Objects Get Charge

Charging by contact: 2 methods
 - Friction
 - Conduction

FRICTION

Rubbing two neutral materials together.
One loses electrons while one gains electrons.



How do we tell which one is positive or negative?
  - Electrostatic Series, P. 473



Ex: A cat plays in your hair.  Which one becomes positive?
A) Cat
B) Hair  <-- positive
C) neither
D) Don't know


How can I make two balloons attract each other?
- Rub one balloon on hair, balloon becomes negative.
- Rub the other balloon on polyester, it becomes positive.
- Since the charges are opposite, they balloons will attract each other.

CONDUCTION

A charged object comes in contact with another object.  Charges move around.

NOTE: ONLY electrons move.

 - The object that is MORE negative will lose electrons.
 - After contact, they will have the same charge.

The green shape is MORE negative, so it loses electrons.

The blue shape is MORE negative, so it loses electrons.

GROUNDING

A charged object comes into contact with a large reservoir of charge.   The charged object becomes neutral.

Ex: Your hand is charged.  You touch a doorknob, you lose charge to the door.

Ex: A balloon sticks to your hair.  You touch the balloon to the floor.  The balloon no longer sticks.

Homework

Read these sections in your textbook to see how electric charges can be applied.
  • Electrostatic Paint Sprayers: P. 470
  • Electrostatic Dusters: P. 475
  • Electrostatic Precipitators: P. 476


Answer these Questions

  • P. 477 #1-3, 5, 6

Thursday 10 October 2013

Oct. 10 – Charges


New Unit: Electricity!

First of all, what is electricity?  Here's an example of electricity in nature:


Learning goals: Understand how to describe charge.

Success Criteria: You can use the idea of charges and static electricity to explain different situations.

Definitions
Electricity: The movement of charges.
Charges: An intrinsic property of matter.

  • Electrons are negatively charged, –
  • Protons are positively charged, +
  • Neutrons have no charge, 0
You can not see or feel charge, you can only tell how it interacts with other charges.

Law of Electric Charges

  • Like charges repel
         (+ repels +)
         (– repels –)
  • Opposite charges attract
         (+ attracts –)
         (– attracts +) 

Static Electricity 
When charges accumulate on an object.

  • An object with more electrons than protons becomes negatively charged.
  • An object with fewer electrons than protons becomes positively charged.
  • An object with the same number of electrons and protons is neutral.

We used the idea of charges attracting and repelling to explain what happens in these situations:

Charges accumulate in his hair.  All the charges are the same, so each hair repels the others.

The cat and ballon have opposite charges, so they attract each other.
Cat vs. Ballon Video: http://www.youtube.com/watch?v=TE2r0vjkXK0


Charges accumulate on the finger and jump to the door nearby.
This person uses the charges from the carpet going through his body to create a light show.
Static Wizard video: http://www.youtube.com/watch?v=8OePt0fSjqs

Finally we discussed the idea of induced charges.

Induced charge:

When a charged object comes near a neutral object, charges can separate in the neutral object.

I used an electroscope to demonstrate induced charges.
I also showed you how you can induced charges in water.

A similar experiment to what I showed you in class.
Homework
  • P. 471 #2-7

Have a great Thanksgiving weekend!

Tuesday 8 October 2013

Oct. 9 – Review

Today we did an in class review to get ready for the test in the form of Jeopardy!

Here's a copy for you to play at home.  Try to answer all the questions to help you study.  The 1000 point questions are particularly challenging.

PowerPoint: Chemistry Review Jeopardy

Good luck in your studies!

Monday 7 October 2013

Oct. 7 – Work Period

Today in Period 1 we had an anti-bullying assembly.  Here is a powerful video on the topic of bullying and how it affects people.

Video: To This Day Project - Shane Koyczan

Here's a live version where you can see the author reciting it in person.

Video: To This Day - Live version

_________________________________________________________________


Then in class I handed back the Physical and Chemical Changes Investigation.  Have a look at TeachAssist for your updated marks.

Here are some notes on your responses:

  • Clarity is either transparent, translucent or opaque.

  • Dissolving is spelt D-I-S-S-O-L-V-I-N-G.  Breaking of a substance without affecting the particles.
    Wrong: the magnesium dissolved.
    Correct observation: I can no longer see the magnesium.
  • Evaporation is a phase change from liquid to gass.
    Wrong: the magnesium evaporated.
    Correct observation: I can no longer see the magnesium.
  • Both dissolving and evaporation are physical changes.


  • "Cannot reverse" is not an observation.
  • You can ONLY use your 5 senses to make observations.
  • Use these observations to support "How do you know".


The rest of the period was for working on the element project and for studying.

Here are some review questions to help you study:
  • Ch. 5, P. 202 #1, 2, 7, 10, 11, 12, 16, 17, 18, 19
  • Ch. 6, P. 248 #1, 2, 4, 5, 6, 7, 10, 11, 13, 14, 19
  • Ch. 7, P. 280 #1, 2, 3, 5, 6, 7, 8, 9

Friday 4 October 2013

Oct. 4 – Naming Chemicals

Here are the solutions to yesterday's homework.




Here we go, the final topic before the test!

Naming compounds

Learning Goals: Understand the conventions in naming chemical compounds.

Success Criteria: Given the chemical formula for a certain compound, you can write down its chemical name.

Handout: Naming Compounds

There are a lot of rules, so take care in reading the handout carefully.

Element Project – Due Oct. 10

Handout: Element Project

In this project you will become an expert on one of the elements in the periodic table.  Use the handout as a guide to what information you should look for.  Then, once you've gather all the information, put it together into a pamphlet (or brochure) that describes that element.  You can do it by hand or typed, but make sure you print it if you use a computer.

Unit Test – Oct. 9

Handout: Topics to study

There will be no new topics between now and the unit test!  For those of you anxious to get started on studying, here are the relevant questions to try from each chapter:

Ch. 5, P. 202 #1, 2, 7, 10, 11, 12, 16, 17, 18, 19
Ch. 6, P. 248 #1, 2, 4, 5, 6, 7, 10, 11, 13, 14, 19
Ch. 7, P. 280 #1, 2, 3, 5, 6, 7, 8, 9

Thursday 3 October 2013

Oct. 3 – Ionic Formulas and Covalent Bonds

Learning Goals:

  • Understand how ionic bonds form.
  • Understand how covalent bonds form.
Success Criteria:
  • You can write the formula for ionic compounds.
  • You can explain how covalent bonds are formed between two non-metals.
Here's an interactive review of what we worked on yesterday:


Next we discussed the patters on the periodic table and how to figure out the ionic charges of each element.

Handout: Valence

Using these valences, we can figure out how many ions of each element are required to make an ionic compound.  I got some volunteers to come up and demonstrate using black and white beads as electrons and protons.  Then we discussed how you can use the crisscross method to figure out the same thing.


Finally we talked about covalent bonds.  Again, students came up to the front to demonstrate using beads as electrons.  In a covalent bond, the atoms don't lose or gain electrons, they share!


If two hydrogen each share their electrons, then they will each have two, making a more stable molecule.  



Here's the example I showed in class of two oxygen forming a covalent bond with a carbon.


Homework: Complete the handouts.

Wednesday 2 October 2013

Unit Test!

The Chemistry Unit Test will be on Wednesday Oct. 9.

We will wrap up the material this week and have a couple days of review before the test.  If there's anything in the unit so far that you are not sure about, please make sure to clarify with me before the test.

Handout: Topics to Study

Oct. 2 – Ionic Bonds

Learning Goals: Understand how ionic bonds are formed.

Success Criteria: You can draw the Bohr-Rutherford diagram for ions and show how they bond.

Today we reviewed som Bohr-Rutherford diagrams and I showed you what Lewis dot diagrams are.  These diagrams are only concerned with the outer shell of each atom.  Here are some examples:


We spent some time discussing the patterns that we see.  All group 1 atoms have one electron in the outer shell.  All nobel gases have complete outer shells.

Here are the handouts for today:
Here's the main idea you should get out of these handouts: ionic bonds form when a metal loses one or more electrons and a non-metal gains the lost electrons.
The Bohr-Rutherford diagrams.

The Lewis dot structures.
Positive and negative ions attract each other and join together forming ionic compounds.
Homework: Complete the handout on Bohr-Rutherford diagrams for ions.


By popular demand, here are the lyrics to the periodic table song!


Written, Directed, Produced, Edited and Sung by Mitchell Moffit.
Based on the "Can-Can" music, by Offenbach. 

LYRICS:

There's Hydrogen and Helium
Then Lithium, Beryllium
Boron, Carbon everywhere
Nitrogen all through the air

With Oxygen so you can breathe
And Fluorine for your pretty teeth
Neon to light up the signs
Sodium for salty times

Magnesium, Aluminium, Silicon
Phosphorus, then Sulfur, Chlorine and Argon
Potassium, and Calcium so you'll grow strong
Scandium, Titanium, Vanadium and Chromium and Manganese

CHORUS
This is the Periodic Table
Noble gas is stable
Halogens and Alkali react aggressively
Each period will see new outer shells
While electrons are added moving to the right

Iron is the 26th
Then Cobalt, Nickel coins you get
Copper, Zinc and Gallium
Germanium and Arsenic

Selenium and Bromine film
While Krypton helps light up your room
Rubidium and Strontium then Yttrium, Zirconium

Niobium, Molybdenum, Technetium
Ruthenium, Rhodium, Palladium
Silver-ware then Cadmium and Indium
Tin-cans, Antimony then Tellurium and Iodine and Xenon and then Caesium and...

Barium is 56 and this is where the table splits
Where Lanthanides have just begun
Lanthanum, Cerium and Praseodymium

Neodymium's next too
Promethium, then 62's
Samarium, Europium, Gadolinium and Terbium
Dysprosium, Holmium, Erbium, Thulium
Ytterbium, Lutetium

Hafnium, Tantalum, Tungsten then we're on to
Rhenium, Osmium and Iridium
Platinum, Gold to make you rich till you grow old
Mercury to tell you when it's really cold

Thallium and Lead then Bismuth for your tummy
Polonium, Astatine would not be yummy
Radon, Francium will last a little time
Radium then Actinides at 89

REPEAT CHORUS

Actinium, Thorium, Protactinium
Uranium, Neptunium, Plutonium
Americium, Curium, Berkelium
Californium, Einsteinium, Fermium
Mendelevium, Nobelium, Lawrencium
Rutherfordium, Dubnium, Seaborgium
Bohrium, Hassium then Meitnerium
Darmstadtium, Roentgenium, Copernicium

Ununtrium, Flerovium
Ununpentium, Livermorium
Ununseptium, Ununoctium
And then we're done!!