1DPHYS - PP1 (Introduction)

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SNC1DPHYSICS

THE CHARACTERISTICS OF ELECTRICITY

L Introduction

(P.388-391)

Unplugged

At about 4:15 pm on August 14,2003, 50 million people in southernOntario and the north-eastern Unitedstates got a surprise when their lightsand appliances flickered, and thenstopped. This was the beginning ofthe largest blackout in history.

July 29, 2014 11DPHYS - Introduction

Satellite photo of eastern North Americashowing the difference in light levelsbefore and during the blackout.

Unplugged

The lights went out. Subways andtrains stopped, trapping commutersfor hours. Traffic signals stoppedworking, causing traffic jams andhazardous driving conditions. On thishot and humid day, people also lostthe use of their air conditioners andfans. More importantly, they losttheir water supply, since the electricpumps could not work.



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Unplugged

NOTE!

Communication was also severelylimited when the cellphone networkwent down. Regular phones didwork, but the system wasoverwhelmed by the number of callsgoing through. Television andinternet were out. For many, theonly way to learn about what wasgoing on was by battery-operatedradios.



Activity: Unplugged

ISSUE

After the blackout, it took days to restoreelectricity to southern Ontario. In Toronto,the streetcars and subways started runningagain four days after the blackout.

INSTRUCTIONS

A. As a small group, discuss the question,“What would life be like if suddenlythere were no electricity?”

B. Record your thoughts on a large pieceof chart paper.


Toronto before and after.

Overall Expectations

By the end of this unit, students will:

1. assess some of the costs and benefits associated with the productionof electrical energy from renewable and non-renewable sources, andanalyse how electrical efficiencies and savings can be achieved,through both the design of technological devices and practices in thehome;

2. investigate, through inquiry, various aspects of electricity, including theproperties of static and current electricity, and the quantitativerelationships between potential difference, current, and resistance inelectrical circuits;

3. demonstrate an understanding of the principles of static and currentelectricity.


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Big Ideas

Concepts that students should retain long after this unit are:

< Electricity is a form of energy produced from a variety of non-renewable and renewable sources.

< The production and consumption of electrical energy has social,economic, and environmental implications.

< Static and current electricity have distinct properties that determinehow they are used.


Getting Started: Useful Concepts & Skills

CONCEPTS REVIEW

1. The photo below shows two ways to generate electrical energy.

(a) What are the two methods shown?

(b) Which way of producing electrical energy do you think has a biggerimpact on the environment? Explain.

(c) Does either method seem harmless? Explain.

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CONCEPTS REVIEW

2. There are often warnings on the back of electrical components, similarto that shown below. What causes the dangers that they warn against.


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CONCEPTS REVIEW

3. Look at the photo below.

(a) Can the design of a building affect how much energy it uses?Explain.

(b) Identify some of the costs and benefits of making your home moreenergy efficient.



CONCEPTS REVIEW

4. Describe the energy change that occurs in the electrical heating systemshown below. What energy is input? What energy is output?



CONCEPTS REVIEW

5. Decide if each action below would have a positive or negative effect onthe environment. Explain your thinking.

(a) hanging laundry outside to dry

(b) using insulation in the walls of a home

(c) burning fossil fuels to make electricity

(d) using skylights to light a home


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SKILLS REVIEW

6. What is unsafe about the actions of the person shown in the diagram?



SKILLS REVIEW

7. A local power company wants to build a hydro-electric dam on a riverthat runs through your town. The dam will be located on part of theriver as shown. The company says the dam will lower the cost ofelectricity in your town.


(a) What advantage is statedby the company? Why?

(b) Are there any otheradvantages, economic orenvironmental, to buildingthe power plant? Explain.

(c) Are there anydisadvantages to buildingthe power plant? Explain.


SKILLS REVIEW

8. Look at the graphs given.

(a) What type of relationship is shown in each (linear or non-linear)?

(b) Make a statement about the relationship between x and y for thegraphs shown. For example, as x increases y __________.


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SKILLS REVIEW

9. Sketch the data given anddetermine if the relationshipbetween money and time is linear.Plot money on the dependent axis(y) and time on the independentaxis (x).


Money ($) Time (h)

10 2

35 7

55 11

70 14

90 18



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1DPHYS - PP1 (Introduction)