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Unit B – Energy Transformations. Chapter 5 – Energy Transformations. In this chapter you will learn: how to identify different types of energy that some energy conversions absorb energy and some release it how energy is converted and that energy is lost with each conversion

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Unit B – Energy Transformations

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Unit b energy transformations

Unit B – Energy Transformations

Chapter 5 energy transformations

Chapter 5 – Energy Transformations

  • In this chapter you will learn:

    • how to identify different types of energy

    • that some energy conversions absorb energy and some release it

    • how energy is converted and that energy is lost with each conversion

    • about the law of conservation of energy

5 1 energy

5.1 - Energy

  • Energy is the ability to do work

  • Energy causes changes in:

    • temperature

    • direction of motion

    • speed

    • shape

Two types of energy

Two Types of Energy

  • Potential Energy is stored energy

  • Examples:

    • chemical energy stored in the food you eat

    • gravitational potential energy when you are at the top of a hill

  • Kinetic Energy is energy due to motion

  • Examples:

    • the flow of electrons (electricity)

    • skiing down a mountainside

5 2 many forms of energy

5.2 – Many Forms of Energy

  • Energy on the Earth originates as solar energy from the Sun

  • Energy from the Sun is converted by plants:

    solar  chemical  kinetic

    (photosynthesis) (cellular respiration)

Unit b energy transformations

  • Energy from the Sun is converted by wind turbines:

    solar  wind  electricity

  • Energy from the Sun is converted by solar panels:

    solar  electricity

5 3 understanding energy conversions

5.3 – Understanding Energy Conversions

  • Energy must get converted so that it is useful

  • Energy entering a system is called input energy

  • System that changes the system is called the converter

  • Energy leaving the system is called the output energy

Unit b energy transformations

  • When energy is converted from one form to another, thermal energy is produced

  • Sometimes heat energy is useful:

    • ie. heat released during cellular respiration heats your body

    • ie. chemical reaction in a “hot pack”

  • When the thermal energy is not useful, it is called waste energy:

    • ie. heat from a light bulb

    • ie. heat from a car engine

5 4 conservation of energy

5.4 – Conservation of Energy

  • Whenever energy is converted by a device, the amount of energy coming out is equal to the amount of energy coming in

Unit b energy transformations

What types of energy are produced by a blow dryer?

  • Thermal energy provides the heat to dry

  • Kinetic energy in the moving air

  • Some electricity is converted to sound energy

  • The glowing elements produce light energy

  • Friction produces thermal energy that is not used to dry your hair.

5 5 energy conversion systems

5.5 – Energy Conversion Systems

  • Some output energy produced during an energy conversion is useful (useful output energy) and some output energy is not (waste output energy)

Unit b energy transformations

  • No energy conversion is 100% efficient

  • When energy is converted from one form to another, thermal waste energy will always be produced.

Pages 98 113

Pages 98 - 113

Chapter 6 – Electric Energy at Home

Chapter 6 electrical energy at home

Chapter 6 – Electrical Energy at Home

  • In this chapter you will learn :

    • about technologies that various forms of energy into electricity

    • how appliances convert electricity into other forms of energy

    • how to calculate the efficiency of electrical devices

    • how to measure electricity and calculate power

    • why it is important to conserve energy

6 1 generating electrical energy

6.1 – Generating Electrical energy

  • In the early 1800s, Michael Faraday discovered that moving a magnet through a coil of copper wire generated an electrical current

  • Faraday used these observations to make the first electric generator

Unit b energy transformations

  • A generator is a device that makes electricity

  • Most electric energy is made in a generator

  • A generator consists of A magnet and a coil of wire.

Unit b energy transformations

Electrical current can be increased by:

  • Increasing the number of coils

  • Using a stronger magnet

  • Moving the magnet/ wire faster

Unit b energy transformations

Energy conversion in a generator:

  • Not all of the kinetic energy is converted into electrical energy. If energy is conserved during a conversion, what happened to the rest of the kinetic energy?

Chapter 6 2 generating and distributing electric energy

Chapter 6.2 – Generating and Distributing Electric Energy

Turbines and Generators

  • Generators contain one or more turbines

Unit b energy transformations

  • In order to make electricity, turbines need to be connected to a generator.

  • As the blades of the turbine turn, their kinetic energy is transformed into kinetic energy in the generator.

  • Kinetic energy in the generator is transformed

    into electrical energy

    kinetic  electrical

Power generating plants

Power Generating Plants

  • Hydro-electric, thermo-electric, and thermonuclear plants all use turbines and generators to produce electricity.

Coal fired thermo electric generation

Coal-fired Thermo-electric Generation

  • Coal in Alberta is cheap and plentiful

  • Emissions pass through a “scrubber” to remove some of the harmful chemicals from the smoke

How it works

How it works:

  • Coal is pulverized and combusted

  • Thermal energy from burning coal converts water to steam

  • High-pressure steam causes turbine blades to turn

  • The spinning turbine turns the generator, producing an electric current

  • The steam leaves the turbine and enters a cooling chamber before returning to the furnace.

Hydro electric plant

Hydro-electric Plant

  • The kinetic energy of falling water is used to produce electricity

Hydro electric generation

Hydro-electric generation

  • What are some possible advantages and disadvantages to using hydro-electric power?

Thermonuclear power plant

Thermonuclear Power Plant

  • Uranium atoms are split by nuclear fission to release large amounts of thermal energy.

  • Thermal energy makes steam.

  • Steam is used to turn turbines, producing electricity.

Unit b energy transformations

  • What are some of the advantages and disadvantages of producing electricity with nuclear energy?

Japan Nuclear Reactor Explanation

Distributing power the power grid

Distributing Power - The Power Grid

  • Electrical generating plants are often located far away from communities.

  • Electricity must be transmitted hundreds of kilometers along power lines.

  • About 10% of energy is wasted as thermal energy as it moves along the power lines.

  • Constructing power plants close to communities creates environmental concerns.

Quick review

Quick Review!

6 3 electrical energy and power

6.3 – Electrical Energy and Power

  • We can measure how fast energy is transferred from one object to another; how fast work is done

  • Power is a measure of the rate of energy transfer

Unit b energy transformations

The formula used to calculate power is:

power is measured in Watts (W)

energy is measured in Joules (J)

time is measured in seconds (s)

  • A generator produces 2 J of energy every second. How many watts of power does it produce?

Unit b energy transformations

  • An aquarium light bulb uses 7 J of electric energy in one second. How many watts of power does it consume in 3 seconds?

Unit b energy transformations

  • Speakers on a computer use 40 J of electric energy. How many watts of power do the speakers consume in one minute (60 seconds)?

Unit b energy transformations

  • You can calculate how much electric energy is consumed by a device by re-arranging the formula:

  • The formula used to calculate how much energy is used is:

    Where energy is measured in watt hours (Wh)

    power is measured in watts (W)

    time is measured in hours (h)

Unit b energy transformations

  • How much electric energy does a 60 W light bulb use if it is left on for 2 hours?

  • How much electric energy does a 240 W fan use if it is left on for 1.5 hours?

6 4 efficiency and saving energy

6.4 – Efficiency and Saving Energy

  • Some devices are better than others at converting electrical energy into useful output energy

  • Which of these devices is more efficient at converting electricity into light? How do you know?

Energy efficient light bulbs

Energy Efficient Light Bulbs…

  • How are they made?

How it’s Made: Fluorescent Bulbs

How it’s Made: Incandescent Bulbs

NatGeo energy efficient bulbs

Unit b energy transformations

  • Device efficiency is expressed as a percentage (%)

  • To determine the efficiency of a device:

  • An incandescent light bulb converts 200 J of electricity into 25J of light. What is the efficiency of the bulb?

Unit b energy transformations

  • An electric kettle uses 240 000J to heat water. 196 000J is actually used to heat the water. What is the efficiency of the kettle?

Unit b energy transformations

  • Using energy efficient devices will benefit:

    • Electrical bills by saving money

    • Environmental by using fewer fossil fuels

Chapter 7 1 energy for life

Chapter 7.1 – Energy for Life

  • Plants convert the Sun’s solar into chemical potential energy stored in glucose (sugar)

  • This is done through the process of photosynthesis

    solar  chemical potential

Unit b energy transformations

  • Animals convert the chemical potential energy in plant and animal cells into mechanical energy

  • This is done through the process of cellular respiration

    chemical potential  mechanical

Unit b energy transformations

  • Animals can get energy from eating plants or from eating other animals

  • Energy stored in the cells of plants and animals is transferred through the food chain

Unit b energy transformations

  • Only 10% of energy is transferred to the next level as it moves through an food chain

  • This is demonstrated by an energy pyramid

  • Less and less energy is available at each level in a food chain

  • Fewer organisms can

    be supported with

    each level

7 2 the need for energy

7.2 – The Need for Energy

  • Our bodies area able to maintain a constant temperature through the process of homeostasis

  • If your body temperature drops:

    • Shivering burns sugar and produces heat

    • Blood is sent to core of the body to preserve heat

  • If your body temperature rises:

    • Blood is sent to skin to release extra heat to air

    • Perspiration transfers heat energy to the air

Unit b energy transformations

  • The rate at which the body uses energy is called metabolism

  • A person with a high metabolism:

    • has high energy needs

    • converts a lot of chemical energy into heat energy

  • A person with a low metabolism has low energy needs

    • has low energy needs

7 3 sources of energy

7.3 – Sources of Energy

  • The main source of energy for humans is glucose, a simple carbohydrate

  • Glucose that is not immediately used by the body may be converted into glycogen for short term storage

  • Glycogen can be easily turned back into glucose

  • Glycogen that is not used is converted into fat for long-term storage

Unit b energy transformations

  • When your body needs to access energy:

  • Glucose is immediately used

  • Glycogen is converted into glucose

  • Fat may be converted back into glucose

  • Muscle protein is converted into glucose

Unit b energy transformations

  • If all energy reserves have been depleted:

    • Body will begin to convert muscle protein into energy

    • This occurs in cases of extreme malnutrition

  • Long term malnutrition results in permanent damage to body organs and structures

7 4 human energy needs change

7.4 – Human Energy Needs Change

  • An individual’s metabolic rate depends on:

    • Age – developing babies and young children have a faster metabolism than adults

    • Time of day – metabolism is highest in the morning

    • Exercise – activity raises metabolism

    • Fitness level – large amounts of energy are required to stay in shape

8 1 what are fossil fuels

8.1 – What are Fossil Fuels?

  • Fossil fuels are formed over millions of years from the remains of once living organisms

  • We can use the chemical potential energy that has been stored in fossil fuels

  • Common fossil fuels:

    • Coal

    • Crude oil

    • Natural gas

Unit b energy transformations

  • Fossil Fuels:

    • are formed from the remains of one living organisms

    • require heat, pressure, and a long time to form

    • contains large amounts of chemical potential energy

How fossil fuels form

8 2 extracting coal and oil

8.2 – Extracting Coal and Oil

  • Fossil fuels must be removed from the ground before they can be of use

  • Coal is quarried or mined, depending on depth

Unit b energy transformations

  • Oil is located deep below the surface and is often difficult to locate

  • A seismic survey uses shockwaves to locate potential locations for oil

Locating Petroleum

Unit b energy transformations


  • Crude oil is oil that is extracted from the ground

  • Crude oil is refined into different products like:

    • gasoline

    • tar

    • motor oil

  • products are separated based on different boiling points

8 3 combustion

8.3 - Combustion

  • Energy stored in fossil fuels is released during combustion

  • chemical potential  thermal

Unit b energy transformations

  • All fossil fuels are hydrocarbons

  • They are made up of hydrogen and carbon

  • When hydrocarbons are combusted they release large amounts of heat and light energy

    CH4 + O2 CO2 + H2O + energy

  • When fossil fuels are combusted, CO2 and H2O are always produced

  • How is the process of cellular respiration similar to combusting a fossil fuel?

Unit b energy transformations

  • Both cellular respiration and the burning of fossil fuels use hydrocarbons as a fuel source

  • Both reaction require oxygen

  • Both reactions produce CO2 and H2O

8 4 the other side of the coin

8.4 – The Other Side of the Coin

  • Because fossil fuels take millions of years to form, they are non-renewable

  • As global populations continue to increase, more people are competing for less oil

  • How is this cartoon related to oil?

Unit b energy transformations

  • Fossil fuels can cause problems when they are transported

Unit b energy transformations

  • The combustion of fossil fuels releases large amounts of CO2 into the atmosphere

  • Excess CO2 in the atmosphere is believed to increase Earth’s natural “greenhouse effect”

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