Principles of electric energy production

Principles of electric energy production - content of pedagogical programme: renewable and non-renewable energy resources, electric energy production, saving electric energy. (Age: 13 – 15 years)

Grade: 7th -9th grade Relation to curriculum: General education – on the field “Fundamentals of Technology and

Science” Physics Understanding of physical phenomena and processes. Transformation of energy types in mechanical and electric processes.

Physics and sustainable development. Evaluation of the impact of various kinds of electric power plants – HPP (big and small), TPP, NPP, WPP – on the environment. Opportunities for improving the quality of environment in connection with electric energy production.

Duration: 3x60 min or 3 academic lessons + time for a field trip Keywords: Renewable energy sources, non-renewable energy sources, wind

power, flow energy of water, Solar battery, electric generator, biomass, nuclear energy.

Content with theoretical background: The use of household appliances, transport, industrial, communication, information and other technologies would be impossible without electric energy. However, we mostly realise the importance of electric energy only in situations when its supply is cut.

The content of the module envisages a chance for pupils to study the varied – both renewable and non-renewable natural resources which can be used for electric energy production and the basic principles of this technological process. In the course of this study, pupils learn to analyse advantages and disadvantages of various kinds of electric power plants in particular regions and evaluate the impact of their construction and exploitation on the environment. Practical activity and evaluation tasks indirectly develop awareness of economical use of electric energy. Educational objectives:

- The pupils are to gain knowledge about the diversity of resources that are used for electric energy production.

- The pupils are to gain knowledge about the technological process of electric energy production.

- The pupils are to evaluate how different types of electric power plants influence the environment.

- The pupils are to develop cooperation and research skills. Learning ambiance: Power plant (TPP, WPP, WPP, or NPP) within a distance accessible to pupils, interest education centre, school. Material: • Pictures of hurricanes and their damage in Latvia (PPt presentation) • A3 sheets of paper • Felt pens

Principles of electric energy production

• Card sets “Electric energy production from renewable energy sources”, “Electric energy production from non-renewable energy sources”

• 1-1.5 V light bulbs • Solar batteries for educational purposes • Jumper wires • 4 permanent magnets (for each group) • Cardboard or plastic • Copper wire coil (0.03 mm) • Nail (8 cm) • Scissors • Sello tape • Prizes Things to be done before the programme: Agree upon the time and content of the field trip with the authorities of the electric power plant. Plan of course (structure):

Time Stages 15´ Introduction. Discussion to create educational context about the significance of electric

energy. 15´ Activating prior knowledge about electric energy production by creating a mind map in

groups. 15´ Didactic game to explore the resources and technological process of electric energy

production. 15´ Complementing the mind map, discussion about similarities and differences of various

electric power plants. 45´ Practical activity: building an electric generator and producing electric energy by using the

electric generator and Solar battery. 15´ Evaluation of different electric power plants/preparation for the field trip. 60´ Field trip to the nearest electric power plant. 60´ Pupils’ presentations, summary, evaluation.

Review of the programme

Time/sta-tion

Contents/course Material

15´/Intro-duction

Pupils are asked to imagine a situation: A hurricane has destroyed the electricity supply system in your town. The responsible services report that electric power supply will be resumed no sooner that in three days. Question: what difficulties will the town dwellers face in the course of these three days? Teacher and the class listen to pupils’ answers. If the lesson takes place at a time when illumination is needed, the teacher may turn off the electricity and begin the lesson by showing what kind of problems it causes. Nothing can be seen, nor read, the prepared presentation cannot be watched, the computers and mobile phones don’t work. Summary of pupils’ ideas leads to evaluation of the importance of electricity in the life of a modern person.

PPt with hurricanes in Latvia

15´/Mind-mapping

A discussion is organised about what is needed to produce, for example, clothes, paper or furniture. Teacher generalises that electric energy production requires natural resources, construction of appropriate equipment and supervision of its operation. Pupils are invited to split into groups of four and try on the role of energy specialists. An announcement is made that at the end of the lesson the

A3 sheets of paper, felt pens

Principles of electric energy production

most knowledgeable group of energy specialists will receive a prize. The groups are given a task: to summarise their previous knowledge and on an A3 sheet of paper create a mind map about electric energy production (resources, equipment, types of electric power plants). If necessary, teacher explains what a mind map is (More info see in http://en.wikipedia.org/wiki/Mind_map and http://www.mind-mapping.co.uk/mind-maps-examples.htm) At the end of the first stage of mind-mapping, groups of pupils give an evaluation of the obtained results (answer the questions: What hampered our work? What knowledge did we lack? What we do and don’t know about electric energy production?

15´/ Didactic game

In order to supplement the yet incomplete mind map and deepen pupils’ previous knowledge of the resources and technological principles used in electric energy production, the teacher distributes envelopes with card sets “Electric energy production from renewable/non-renewable natural resources”. To get familiar with the cards and prepare for the game, the groups are invited to logically arrange the given cards in four columns, beginning from the primary energy source (the Sun or Earth). When the pupils are familiar with the cards, they are invited to play the game according to the rules.

Card sets “Electric energy production from renewable/ non-renewable natural resources”

15´/Supple-menting the mind map

Pupils are encouraged to supplement their mind maps with the information they learnt during the game. In the arranged lines of cards, pupils are encouraged to find similarities and differences in energy production from various natural resources. Pupils are asked to note the common principles of electric energy production in the mind map. Each group is invited to read their conclusions out loud. The group whose conclusions are the most precise is praised. A conclusion is made that the main things that are needed to produce electric energy are:

1) appliance that transforms mechanic energy into electric energy – that is, an electric generator;

2) resources – fuel or water, flow of steam or wind to operate the electric generator;

3) knowledge about the electric and magnetic phenomena.

45´/Work with the constructor

Pupils are informed that energy specialists need not only theoretical knowledge, but also practical skills. Depending on opportunities, pupils are offered to perform one or two practical tasks. 1. Each group of pupils is given a set of Solar batteries and light bulbs (1 - 1.5 V) and asked to check how batteries work. (Output wires of the Solar battery have to be joined with the light bulb. When the battery is turned towards light, the light bulb has to glow.) It is advisable to demonstrate the work of Solar battery by using an INTERNET animation: http://www.suntech-power.com/flash/solarcells.swf 2. Each group is given instructions and provided with the equipment for making an electric generator. Groups are asked to make and test an electric generator, and explain how it works. Afterwards, each group operates the newly created generators, e.g. producing enough electric energy to light a bulb. Each group is asked to explain the principle of generator’s operation and say whether it can be improved. Pupils’ accomplishments are summarised: the lesson promoted deepening of both theoretical knowledge and practical skills. The most skilful/careful group of experimenters is praised.

Equipment for making a generator, Solar battery, light bulb, jumper wires

Principles of electric energy production

Additional information can be found in: http://amasci.com/amateur/coilgen.html or http://www.metacafe.com/watch/912594/simple_electric_generator/ For more information see video in: http://amasci.com/amateur/coilgen.html or http://www.metacafe.com/watch/912594/simple_electric_generator/

60´/Field trip

Field trip to an electric power plant (HPP, NPP, TPP, WPP) in the neighbourhood. Aim of the field trip: visit an electric power plant in the neighbourhood and find out if the local power plant corresponds to the principles of maximally effective and environmentally friendly electric power plant and compare it to power plants of other kinds. Additional information: http://www.latvenergo.lv/pls/portal/docs/PAGE/LATVIAN/ZINI_ELEKTRIBU/zini_elektribu.pdf

60´/Re-ports, summary

After the field trip groups are given some time to come together and summarise the obtained information as well as prepare a report. After hearing the reports, conclusions and summary are made. Pupils are encouraged to evaluate what new knowledge they have obtained, what they liked most or less about the lesson. Prizes are given to the most knowledgeable and careful “energy specialists” (for creating the most informative mind map and the best electric generator), and “counsellors” of ministers (for the most informative report).

Prizes and/or diplomas

Teachers from other countries can find and compile a list of electric power plants in their neighbourhood, contact them and evaluate the possibilities of collaborating with them in pupils’ energy education.

Principles of electric energy production

Background information: principles of electric energy production

- content of pedagogical programme: renewable and non-renewable energy resources, electric energy production, saving electric energy.

1. Electricity 2. Production of electricity 3. Thermal power plants 4. Hydroelectric power plants 5. Nuclear power plants 6. Animations and video about power plants

1. Electricity Electricity - all phenomena caused by electric charge, whether static or in motion. Electricity generated on a commercial scale was available from the early 1880s and used for electric motors driving all kinds of machinery, and for lighting, first by carbon arc, but later by incandescent filaments, enclosed in glass bulbs partially filled with inert gas under vacuum.

Other practical applications include telephone, radio, television, X-ray machines, and many other applications in electronics.

In 1800 Alessandro Volta found that a series of cells containing brine, in which were dipped plates of zinc and cooper, gave electric current, which later in the same year was shown to evolve hydrogen and oxygen when passed through water.

Michael Faraday demonstrated in 1831 the first dynamo, which became basis of electrical engineering.

Electricity is the most useful and convenient form of energy, readily convertible into heat and light and used to power machines. Electricity can be generated in one place and distributed anywhere because it readily flows trough wires. 2. Production of electricity Electricity is generated at power stations where a suitable energy source is harnessed to drive turbines that spin electricity generators. Electric generator is a device for converting mechanical energy into electricity, usually by electromagnetic induction, the production of voltage in an electrical conductor when it is a changing magnetic field or it moves in relation to a steady magnetic field.

Current energy sources are coal, oil, water power, natural gas, and nuclear energy. Research is under way to increase the contribution of wind, tidal, solar, and geothermal

power. Nuclear fuel has proved more expensive source of electricity than initially anticipated and worldwide concern over radioactivity may limit its future development.

The systems mentioned above are systems for changing mechanical energy into electricity. Every form of energy, heat, light, gravity, geothermal energy, solar radiation can be directly

(without change in mechanical energy) changed into electricity, but at present technological level of development it is not a solution to energy problems. 3. Thermal power plants

In thermal power plants fuel is burnt to obtain very hot compressed steam. The steam drives turbines, which, in their turn, spin generators of electric current. This way 30-40% of fuel energy is transformed into electric energy. After passing through a turbine, steam is still hot enough to be used for central heating of the city. A power plant which apart from electric energy produces thermal energy is called a combined heat and power plant (CHPP).

In many places around the world, thermal power plants still represent the simplest and thus the cheapest solution to electric energy production. Nevertheless, it is also the most environmentally unfriendly way – non-renewable energy resources are burnt and a greater or lesser amount of

Principles of electric energy production hazardous emissions is released in the atmosphere. Compared with black diesel or coal, natural

gas is the most environmentally-friendly fuel.

4. Hydroelectric power plants

In hydroelectric power plants flow energy of water is used for energy production. A dam is built on a river, to collect a greater amount of water in the reservoir. When the dam is opened, water flows through the penstock with great might, thus driving the turbine. The turbine in its turn spins the generator that transforms flow energy of water into electric energy which is further transmitted into electrical power networks.

Hydro energy is more environmentally-friendly – mostly because it does not produce hazardous waste. Yet, it can cause serious problems. In order to make a water reservoir, it is often necessary to flood vast areas that can contain habitats of rare plant and animal species, significant historical landmarks and picturesque landscapes. Furthermore, the river ecosystem is destroyed – occasionally numerous fish species suffer the consequences when the dams block their natural migration routes.

5. Nuclear power plants Nuclear power plants function in a similar way to thermal power plants, only the steam for driving the turbine is heated by using nuclear fission energy. This process of energy production is the most environmentally-friendly – provided that certain safety measures are observed, no hazardous waste is released in the environment, there is no need to significantly transform vast areas of landscape and no major use of non-renewable energy resources is required.

Nevertheless, use of nuclear power is related to numerous problems. First of all, this is a relatively expensive technology and only rich countries and major companies can afford it. Secondly, radioactive matter is extremely hazardous to human health and life. In case of a sudden accident in a nuclear power plant or a radioactive slag store, the consequences could indeed be devastating. Thirdly, the technology of producing nuclear power is quite easily adaptable to producing nuclear weapons and fallen into the hands of a criminal regime or persons can seriously threaten global security. Source about electric power plants: http://www.latvenergo.lv/pls/portal/docs/PAGE/LATVIAN/ZINI_ELEKTRIBU/zini_elektribu.pdf 6. Animations and video about the power plants If the excursion with pupils to some power plant is impossible, you can show them some animations or video materials about power plants (in English): Coal-fired power station animation http://www.footprints-science.co.uk/power.htm How our power stations work? (Coal Power Station, Hydroelectric Power Station, Combined Cycle Power Station, Wind Power Station http://www.saskpower.com/poweringyourfuture/today/generation/animation.shtml Several video clips about hydroelectric power stations http://videos.howstuffworks.com/hsw/6194-energy-hydroelectricity-video.htm Video about a coal power station http://www.youtube.com/watch?v=SeXG8K5_UvU Description and video about the principles of work of nuclear power station http://www.darvill.clara.net/altenerg/nuclear.htm Searching the Internet teachers or pupils themselves can find a large number of similar animations or videos about the work of different power stations.

Principles of electric energy production

Set 1. Didactic game “Energy Production by Using Renewable Energy Sources”

Aim: Learn about the primary sources and technological principles of energy production. ...................................................................................................................................

Description of the game. The game contains 28 double cards that are designed as domino dice. The game requires 2-4 participants. Each participant gets 7 double cards. If there are 2 or 3 players in the game, the remaining cards are put on the table. The game is started by the player who has the card with the image of the Sun – the chief primary source of energy. If nobody has this card (or any other card that is needed further during the game), players in turns take one card from the pile until the right card is found. The aim of the game – create four logically sequenced chains of cards and get rid of the cards as soon as possible. The cards are put on the table so that the upper cell of the following card would cover the upper cell of the previous card.

...................................................................................................................................

Description of the game. The game contains 28 double cards that are designed as domino dices. The game requires 2-4 participants. Each participant gets 7 double cards. If there are 2 or 3 players in the game, the remaining cards are put on the table. The game is started by the player who has the card with the image of the Sun – the chief primary source of energy. If nobody has this card (or any other card that is needed further during the game), players in turns take one card from the pile until the right card is found. The aim of the game – create four logically sequenced chains of cards and get rid of the cards as soon as possible. The cards are put on the table so that the upper box of the following card would cover the upper box of the previous card.

...................................................................................................................................

Description of the game. The game contains 28 double cards that are designed as domino dices. The game requires 2-4 participants. Each participant gets 7 double cards. If there are 2 or 3 players in the game, the remaining cards are put on the table. The game is started by the player who has the card with the image of the Sun – the chief primary source of energy. If nobody has this card (or any other card that is needed further during the game), players in turns take one card from the pile until the right card is found. The aim of the game – create four logically sequenced chains of cards and get rid of the cards as soon as possible. The cards are put on the table so that the upper box of the following card would cover the upper box of the previous card.

Principles of electric energy production

The cards are cut along the triple lines. The cards from Set 1 and Set 2 could be in different colour.

The Sun – the chief energy source

The Sun – the chief energy source

The Sun – the chief energy source

The Sun – the chief energy source

Solar energy

diffuses as radiation

The Sun – the chief energy source on the

Earth

Solar energy diffuses as radiation

Solar energy ensures water

circulation in nature

Solar radiation is one of the factors that ensure plant

growth and formation of biomass

Solar energy ensures flow of air –

the wind

Solar energy is

commonly called light and heat

and flow of water in

rivers

Solar energy ensures flow of air –

the wind

Solar energy is a renewable energy

source

Flow of water in rivers – a renewable

energy source

Biomass is a renewable energy

source

The wind – a

renewable energy source

Solar energy can be

transformed into electric energy

Flow energy of

water can be efficiently used

In a thermal power

plant thermal energy is obtained by

burning biomass

Principles of electric energy production

The wind as an energy source operates a wind

generator

To produce electric

energy we need Solar energy equipment!

Flow energy of

water can be transformed into electric energy

Thermal energy is needed to obtain

steam

Daugavpils TPP

Wind generator

Solar panels or Solar batteries

For this purpose hydroelectric power

plants are built

In a thermal power

plant steam flow turns a

steam turbine

Wind generator transforms the

energy of the flow of air into electric

energy

Solar batteries

consist of many cells

Wind generator transforms the

energy of the flow of air into electric

energy

In every cell of the battery Solar energy is transformed into

electric energy

The steam turbine operates the generator

Electric energy is transmitted to the consumer through

electric transmission lines and cables

Flow of water turns

the turbine, while the turbine turns the rotor

of the generator

The generator produces electric

energy

Pļaviņas HPP

In a HPP the most important eguipment is the turbine and

the generator

Principles of electric energy production

Electric energy can be easily transformed into another kind of energy, e.g. light

energy

In every cell of the

battery solar energy is transformed into

electric energy

Generator is a

device that transforms the flow energy of water into

electric energy

Electric energy can be easily transformed into another kind of

energy, e.g. mechanical energy

For this purpose an

electric engine is used

Set 2: Cards for the Didactic game “Energy Production by Using Non-Renewable Energy Sources”

Rules of the game are the same as in the first case. The game is started with the card that depicts the Earth.

Mineral deposits – non-

renewable energy resources

Mineral deposits – non-

renewable energy resources

Mineral deposits – non-renewable energy resources

Oil – non-renewable

energy resource

Natural gas – non-renewable energy

resource

Coal – non-

renewable energy resource

Uranium ore – non-renewable energy

resource

Oil products are

used as fuel

Natural gas – a widely

used fuel

Coal – a widely used

fuel

Uranium ore is a mineral

Petrol, paraffin, black

diesel are oil products

Electric energy is easily transmitted

across great distances

Energy produced in the Solar battery is collected in the

accumulator

Principles of electric energy production

In thermo electric

power plants (TPP) black diesel is used

as a fuel

In thermo electric

power plants (TPP) natural gas is used as

a fuel

In thermo electric

power plants (TPP) coal can be used as a

fuel

Uranium obtained

from uranium ore is used as a fuel in

nuclear power plants (NPP)

for production of heat and steam

for production of heat and steam

for production of heat and steam

In TPP steam flow turns the steam

turbine

In TPP steam flow turns the steam

turbine

In TPP steam flow turns the steam

turbine

The main part of a NPP is the nuclear

reactor

There neutrons are used to split the

nuclei of uranium atoms

The steam turbine operates the generator

The steam turbine operates the generator

The steam turbine operates the generator

When nuclei of

uranium atoms are split, a great amount of energy is released

Generator produces electric energy

Generator produces electric energy

This energy is used to produce steam

Principles of electric energy production

Generator consists of a mobile part – rotor

and a static part – stator

To make a simple

generator model we need a magnet and a

twine of wires

NPP also has a steam turbine that

operates the generator

through electric

transmission lines to the consumers

Electric energy is produced when the

rotor is turning in the stator

Generator produces

electric energy

Consumers, by using appropriate

appliances, transform electric energy into

e.g. mechanical energy

Electric energy can be easily transformed into another kind of energy, e.g. light

energy

When the twine is

turning between the poles of the magnet, voltage is created on the ends of the twine

Electric energy is transmitted to the consumer through

electric transmission lines

Voltage above 42 V can kill!

Electric energy is easily transmitted across great distances

Principles of electric energy production

Build a simple electric generator

Equipment

• 4 - 1x2x5cm ceramic magnet: Edu. Innv M-700, or Radio Shk #64-1877, or CMS • 1 - #30 Magnet wire 200ft, Radio Shack spools #278-1345 • 1 - Miniature Lamp, 1.5V 25mA Rad. Sh. #272-1139, or All. LP-3 or #48 lamp • 1 - Cardboard strip, 8cm x 30.4cm • 1 - Large nail, 8cm long or more • Misc. - Knife or sandpaper to strip the wires • Misc. - tape to hold wire down • Sellotape

Instruction

Make the Open- ended Box

• Score the cardboard strip (or cut the Plexiglas or wood) where indicated by the vertical dotted lines:

_______________________________________________ | 8cm | 3.5cm | 8cm | 3.2cm | 7.7cm | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |________ __|____ __|________ ___|______|_______ __ _|

• Next, fold the strip like this and tape it securely (or glue the Plexiglas

or wood pieces together). Note: If you build the box from Plexiglas or thin wood instead, don't make it any larger than shown above. The wire should be very close to the spinning magnets, so keep the box as small as possible.

• With the open ends of the box at the top and bottom, use the nail to carefully poke a hole perfectly straight through the center of the cardboard box, going through both sides and all three layers of it.

• Pull the nail out and use it to widen all the holes slightly, so when you put the nail back through, it will be a bit loose and able to spin. (If using Plexiglas or wood, to drill a hole through the center of the box.)

• Put the nail through the hole in the box. • Stick your four magnets together face-to-face in two pairs. • Put the two pairs on either side of the nail (inside the box) so they

grab the nail. Give the nail a spin.

Note: The nail and magnets should spin freely. The corners of the magnets should NOT bump the inside of the box as they spin. If the box is a bit too small, either: make a new box, a little bit bigger.

Principles of electric energy production

Wind the Magnet Wire around the Box

• Position the box so the open ends are on the top and bottom as shown. Pick the spool of 30-gauge magnet wire (the thinnest wire) from the kit of spools.

• Tape one end of the magnet wire to the side of the box, then wind the entire spool of wire horizontally onto the box as shown (it's OK to cover up the nail hole).

• Pull the taped end of the wire out, then tape down both of the wires about 10cm from the ends so the coil doesn't unwind.

• Use the sandpaper to scrape the thin coating off 2cm of the wire ends. Remove every bit of coating, so the wire ends are coppery. Clean the Wire Ends Thoroughly

• Spread the center of the wire bundle away from the nail hole and tape it in place.

Place the Magnets around the Nail

• As when you tested the box size above, again stick the four magnets together face to face in two pairs, then stick the two pairs on either side of the nail (inside the box) so they grab the nail.

• Push the magnets around until they are somewhat balanced and even, then spin the nail and see if they turn freely.

• If you wish, you can push 2cm squares of cardboard between the magnet pairs to straighten them. You can also tape the magnets so they don't move around on the nail.

Add the Light Bulb

• Make sure that each end of the generator's wires is totally cleared of red coating. If there is a bit of coating left, it can act as an insulator, which turns off your light bulb circuit.

• Twist one of the scraped ends of generator wire securely around the silver tip of one wire from the small light bulb, and the end of the other generator wire around the tip of the other light bulb wire. In the twisted wires, metal must touch metal with no insulating coating in between.

Test Your Generator

• Spin the nail/magnet combination REALLY fast; the bulb should light dimly. If you don't see the bulb light up, try spinning it in a dark room so you don't miss the dim glow.

• If needed, adjust the position of the magnets so they don't hit or scrape the sides of the box. The nail/magnet assembly must spin VERY FAST, and it slows down if the magnets hit the box.

• Once you get it to work, try clamping the point of the nail into the chuck of a hand-cranked drill.

• Spin the nail/magnet assembly fast with the drill and the bulb will light brightly. Note: Don't go too fast or you'll burn out the bulb or fling magnets all over the room. You can also try an electric drill, although electric drills don't spin as fast.

Note: Your generator produces Alternating Current, not Direct Current.

Principles of electric energy production

The output voltage is about 2 volts max, so there is no electric shock hazard.

How to Improve Your Generator

• You can make your generator more powerful by using more turns of wire. You used only the spool of 30-gauge wire; with more wire, the magnets don't have to spin as fast to light the bulb.

For more information see video in: http://amasci.com/amateur/coilgen.html or http://www.metacafe.com/watch/912594/simple_electric_generator/ Magnet warning!

Keep the magnets away from computers, disks, videotapes, color TV sets, and wallets and purses containing credit cards.

How a simple electric generator works Electric Charge. All metals contain a movable substance called electric charge. Even uncharged wires are full of charge! The atoms of the metal are made half of positive protons and half of negative electrons. Metals are special because their electrons don't stay connected to the metal atoms; instead they fly around inside the metal and form a type of electric "fluid" inside the wires. All wires are full of this electric fluid. Modern scientists call this the electron sea or electron gas. It is not invisible; it is something like a silvery fluid, and actually gives metals their silvery shine. A Circuit. When a circle of wire surrounds a magnetic field, and if the magnetic field then changes, a circular "pressure" called Voltage appears. This circular voltage tries to force the movable charges inside the wire to rotate around the circle. In other words, moving magnets cause changing magnetic fields which try to create electric currents in closed circles of wire. A moving magnet causes a pumping action. If the circuit is not complete, if there is a break, then the pumping force will cause no charge flow. Instead, a voltage difference will appear at the ends of the wires. But if the circuit is "complete" or "closed", then the magnet's pumping action can force the electrons of the coil to begin flowing. A moving magnet can create an electric current in a closed circuit. The effect is called Electromagnetic Induction. This is a basic law of physics, and all coil/magnet electric generators use it.

Generators don't have just one circle of wire. Suppose that many metal circles surround the moving magnet. Suppose that all the circles are connected in series to form a coil. The small voltage from each circle will add together to give much larger voltage. A coil with 100 turns will have a hundred times more voltage than a one-turn coil.

Light bulb. Now for the light bulb. If we connect the ends of the coil together, then whenever the magnet moves, the metal's charges will move and a large electric current will appear in the coil. What if we instead connect a light bulb between the ends of the coil? A light bulb is really just a piece of wire. The charges of the light bulb's filament will be pushed along. When the charges within the copper wire pass into the thin light bulb filament, their speed greatly increases. When the charges leave the filament and move back into the larger copper wire, they slow down again. Inside the narrow filament, the fast-moving charges heat the metal by a sort of electrical "friction". The metal filament gets so hot that it glows. The moving charges also heat

Principles of electric energy production

the wires of the generator a bit, but since the generator wires are so much thicker, almost all of the heating takes place in the light bulb filament.

So, just connect a light bulb to a coil of wire, place a short powerful magnet in the coil, then spin the magnet fast. The faster you spin the magnet, the higher the voltage pump-force becomes, and the brighter the light bulb lights up. The more powerful your magnet, the higher the voltage and the brighter the bulb. And the more circles of wire in your coil, the higher the voltage and the brighter the bulb.

Feel the Electrons. When your hand spins the magnet, you can feel the extra work it takes to light the bulb. This happens because your hand is connected to the flowing charge in the bulb, and when you push on it, you can feel it push back on you!

How is your hand connected to the flowing charges?

• Your hand twists the nail, • the nail spins the magnet, • the magnet pushes the invisible magnetic fields, • the fields push the movable charges, • the charges flow slowly through the light bulb filament, • and the tiny filament causes friction against the flow of charge and heats up.

Motor Challenge

There is a simple way to convert your generator into a motor:

• Use paint or tape to insulate a spot on one side of the nail. • Use a 4,5V battery and the generator's wires to touch the nail, forming a switch. • The rotating magnets turn the nail, which turns the coil on and off at just the right times.

Other possibilities to built electric generator see:

• http://www.creative-science.org.uk/8blade.html • http://mike-thomson.com/blog/?cat=9 • http://micro.magnet.fsu.edu/electromag/java/generator/ac.html • http://wzlianying.en.alibaba.com/product/200010489/51355668/Hand_Driven_DC_AC_G

enerator.html

Hurricanes and Their Damagein Latvia

Module: “Principles of electric energy production”

Carnikava, 2001.01.11. Source: www.latvijasdaba.lv

Randu Meadows, 2005. 09.01. Source: www.latvijasdaba.lv

Liepaja, 2008.09.07. Source: http://www.tvnet.lv/zalazeme/

Saulkrasti, shore of the Gulf of Riga, 2005.09.01. Source: www.latvijasdaba.lv

Red Cliffs, Vidzeme seashore, 2005.09.01. Source: www.latvijasdaba.lv

North-Vidzeme biosphere reservation, 2005.09.01. Source: www.latvijasdaba.lv

Selija, 2008.07. Source: www.poga.lv

Selija, 2008.07. Source: www.poga.lv

Selija, 2008.07. Source: www.poga.lv

Selija, 2008.07. Source: www.poga.lv

Selija, 2008.07. Source: www.poga.lv