Sciences Subject (BS11001)

201 wet season is called a rainstorm. It is caused by the same factors as the summer storm but is less damaging. Some kinds of storms cause loss of life and property damage. Storms can develop into tropical storms and typhoons such as the typhoon “Gay” which hit Thailand at Chumporn Province on 4 November 1989. When a typhoon makes landfall, it can cause severe and widespread damage to towns or villages it strikes. As a preventive measure, you should keep abreast of news related to storms from the radio, television or newspaper and be prepared beforehand. It is safer to stay at home or, if you are sailing, return to the shore as soon as possible and keep abreast of storm warnings. In case of floods from heavy rain, humans and animals should be evacuated to safe and dry places which are above the flood level or far from the shore and protected from storm winds. An anemometer is an invention designed for measuring the wind speed. Anemometers which are commonly used consist of hemispherical cups with the hollow side of each cup set to catch wind. The cups are spun by the wind. The turns of the cups are relative to the distance the wind travels over a set time period and thus can indicate the wind speed. An anemometer should be attached to a rod and placed at a location where wind flow is unobstructed by, for example, buildings or trees. It should be approximately 10 meters above the ground. When the wind blows over the water surface, waves will form. The height of the wave is relative to the strength of the wind. Generally, an anemometer and a wind vane are installed together. Anemometer

202 Tropical cyclone A tropical cyclone refers to a cyclone forming over the tropical sea or ocean located between the latitudes of 30 degrees north and 30 degrees south. In metrology, tropical cyclones forming over the tropical seas or oceans are classified into categories based on their maximum wind speed near the center as follows: Category Wind speed near the center Depression A maximum of 61 kilometers per hour Tropical storm 70-120 kilometers per hour Typhoon A minimum of 120 kilometers per hour Names of storms vary with their geographical origins. For example: 1. Storms forming over the Bengal Bay and the Indian Ocean are called cyclones. 2. Storms forming over the North Atlantic Ocean, the Caribbean Sea and the Mexico Bay are called hurricanes. 3. Storms forming around Australia are called Willy-Willy. 4. Storms forming over the Pacifica Ocean and the China Seas are called typhoons. A tornado which is also known as a twister typically forms as a rotating column of air. It is visible as a funnel of dust swirling up into the air. Tornado

203 Tornadoes can occur in any continent but the areas which see tornadoes most often and almost throughout the year are the Australian continent and the United States of America. Tornadoes are highly destructive. They can cause damage and kill humans and animals. Tornadoes are typically accompanied by thunders and heavy rains or even strong gusts or hails. Tornadoes form in clouds which develop rapidly in vertical movement. Apart from its destructive force, wind has numerous benefits to humans. It is useful for sailing and drying clothes and helps cool down the heat. With the wind power, we can pump water by using windmills and water mills or generate electricity. In addition, wind energy is environmentally friendly. Wind power can generate electricity

204 Lesson 13 The Profession of an Electrician Main learning essence Being an electrician is one of the interesting and well-paid professions. There are many kinds of electricians, each with totally different roles and responsibilities. Electricians working in large construction sites use instruments and skills which are different from those working in large industrial factories. However, electricians are generally required to possess the basic electrical knowledge, be able to understand electric circuit blueprints and fix electrical appliances. At present, most electricians work for electrical contractors or large industrial factories. In addition, a large number of electricians work as freelance contractors. Some work for government or business organizations as in-house electricians. Although job opportunities for electricians are available nationwide, the jobs are concentrated in industrial or developing areas. Expected learning outcome Be able to explain, design, plan, experiment, and test electrical works correctly and safely and be able to think, analyze, compare advantages and drawbacks of series circuit, parallel circuit, and compound circuit. Know how to appropriately apply and adopt the knowledge and electrician skills to manage tasts and services. Content scope 1. Electricity types 2. Electrical equipment and tools 3. Electric circuit equipment 4. Basic electric circuits 5. Ohm’s law 6. Basic electrical wiring 7. Basics of use of electrical appliances 8. Safety and accidents in electrical professions 9. Management and service 10. Scientific projects for the profession

205 11. Electrical terms 1. Electricity can be classified into 2 groups as follows: 1.1 Static electricity is the electricity stored in an object. It is created when 2 objects are rubbed together. For examble, when an amber rod and wool are in contact, the amber rod transfers electrons to wool. So, it means that the amber rod has negative charge and wool contains positive charge. Wool Amber rod 1.2 Current electricity is a flow of electrons from an electric source through a conductor to the outlet, driven by pressure, heat, light, chemical reaction, and magnetic field. There are 2 types of current electricity as follows: 1) Direct current (DC): It is an electric current which flows in a constant direction and volume. Common direct current sources are batteries and dry batteries. An adapter is needed for transforming electric current to direct current. Switch Battery Switch Battery off on Light on Light out (A) Closed circuit (B) Open circuit

206 2) Alternating current (AC): The flow of electric charge periodically reverses direction and changes volume. Alternating current is used in households for the lighting system, radio receivers, televisions, fans, etc. 2. Electrical equipment and tool Important electrical equipment and tools include: 2.1 Screwdriver which consists of 2 types: 1) Common screwdriver 2) Phillips screwdriver or cross-slot screwdriver The size and thickness of the tips of the 2 screwdrivers are different, depending on the size of the screw head used for loosening or tightening screws. To tighten screws, the screwdriver must be rotated clockwise. To loosen screws, the screwdriver must be rotated counterclockwise.

207 Another type of screwdrivers specifically used only for electric works is a spark detecting screwdriver. It is has a light bulb on the handle and is used for testing electric circuit. 2.2 Knife mostly used in electrical works for stripping electric insulators includes a pocket knife or cutter. This is how to use a knife to strip electric wires correctly: 1. Girdle the outer jacket 2. Cut the middle jacket 3. Separate the wires 3. Plier is used for squeezing, cutting, and rolling electric wires. It can be classified into: 1) Diagonal plier is a side cutter used for cutting twisted wires, flexible twised wires and small power wires and cables. 2) Combination plier is a type of pliers used for gripping, pulling, or twisting small electric wires. 3) Flat nose plier is used for cutting, squeezing or twisting electric wires.

208 4) Mini round nose plier is used for creating loops in pieces of wire (curling wire tips to fasten electric wires with the main wires) 5) Wire stripping plier is used for stripping electric insulators, flexible twisted wires, and power wires and cables. A wire stripping plier is used for cables with specific copper wires. A wire stripping plier should be covered with an insulator, such as plastic, to prevent current leakage or electrical shock. 2.4 Drill is used for drilling holes to fasten electrical appliances such as switches, lamps, or wooden boards by screws. Holes must be made using a drill or a gimlet. There are 3 types of drills: 1) Bit drill 2) Hand drill 3) Electric drill

209 The selection of drills and drill bits should be based on the size of electrical appliances and tasks. For simple for drilling wooden boards, hand drills or bit drills may be used. Electric drills should be used for metals, concrete or cement floors. 2.5 Hammer is used for nailing to fasten clips to the wall, or center drill tasks for drilling metal, concrete or cement floor. Hammers used for each task are different in size and weight but the ones that are commonly used weigh 200 grams. Caution The head of the hammer must be well tightened to the wood handle. In addition, the head must be hardened. 3. Electric circuit equipment 3.1 Electrical cable - Electrical cable is an equipment for transferring electrical power from one point to another point. Current runs along an electric cable carrying electricity to an electrical appliance. Electric cables made of conducting materials (materials which permit a flow of electric charge) are: 1) High voltage cable ‟ It uses aluminum which is cheaper and lighter than copper as a conductor. 2) General cable (for home use) ‟ It uses copper which is cheaper than silver as a conductor. Picture A Picture B A. Heat resistance wire is made of heat resistance Picture C Picture D insulators such as an iron wire. B. Pair wire is used for household electrical wiring. C. Flexible pair wire is used for household electrical appliances such as radios and televisions. D. THW wire is used for electrical conduit.

210 3.2 Fuse - It provides overcurrent protection by automatically breaking the circuit of electricity when there is an excessive current. Fuse is made of an alloy composed of lead, tin and bismuth. Fuse has a low melting point and high resistance. There are various types of fuses to serve different purposes. Fuse wire Blade fuse Ceramic fuse Cartridge fuse 3.3 Switch - It is a device for connecting and breaking an electrical circuit at a specific spot. Its function is similar to the function of a circuit breaker. Switch is connected in series with electrical appliances. There are 2 switch types: single-throw and double-throw. Circuit 1 Circuit 2 3.4 Circuit breaker - It is a device for interrupting or connecting all electrical circuits in a house. It has a frame and a lever which has an insulated handle and 2 strips of metal. When the level is down, electric current flows from a meter to an electric circuit. Pushing the lever up will stop the current flow. Insulator Conductor Fuse

211 3.5 Starter ‟ It is a device other than the main switch used for connecting or breaking preheat start of the bulb. There are 2 types of starters as follows: Type 1 - Starters without operating time limitation Type 2 - Starters with operating time limitation, which consist of 3 types, namely: 1) Starters which cannot reset time. 2) Starters which can reset time. 3) Starters which can reset time automatically by using the main switch or other designed means, to start the bulb. 3.6 Ballast ‟ It is used to increase electrical potential difference. It has a high resistance to alternating current. There are 2 types of ballast: 1. Electromagnetic ballast 2. Electronic ballast. 1) Electromagnetic ballast is a ballast with wires around an iron bar. It acts as a reactor connected with the bulb in series. Picture of electromagnetic ballast 2) Electronic ballast - It is a ballast using electric circuit to function. It is costly but has more advantages over an electromagnetic ballast which include the ability to increase bulb effectiveness, no flickers or flashes, being workable without starters, increasing the bulb life, and there is no need to improve the power factor (P.F.), no disturbance sound, and is light weight.

212 Picture of an electronic ballast 3.7 Electric current meter We can check the electric current in a wire by hanging a magnet bar close to the wire and observe the deflection of the magnetic bar. This idea led to the invention of meters. The deflection of the scale pointer can indicate the volume of electric current and can be used to measure the electrical potential difference. Galvanometer is an instrument for detecting direct current, using the same principle as the magnetic field. The simplest form of galvanometer is to place a compass close to a wire to check if there is electric current flowing through the wire. Moving-coil galvanometers use the principle of motor to display the deflection of the pointer. Ammeter is an instrument used for measuring the electric current made from coil galvanometers. It is designed to make the pointer deflect through scales. To measure high electric current, a shunt is needed to enable the pointer to deflect fully. Voltmeter is an instrument used for measuring electrical potential difference between 2 points. It is made of a galvanometer connected in series with a high resistance. A certain degree of electrical potential difference releases electric current that enables the pointer to deflect fully. To measure high electrical potential difference, use a multiplier. Multimeter is a galvanometer connected with a shunt (see ammeter) and multiplier (see voltmeter). It is used for measuring the electric current and electrical potential difference. Moving-iron meter is used for measuring electric current, which creates electromagnetic induction in 2 magnetic bars to pull or push each other, causing deflection on the magnetic bar.

213 4. Building electric circuit Electric circuit is the path of flowing electric charges. The flow can occur when an electric source is connected with a copper wire and 1 or 2 electrical appliances such as resistance switch, ammeter, voltmeter or light bulb. Electric current flows from the electric source and moves around the connected circuit. Resistance Electric circuit with connecting instruments and electric circuit chart Scientists use symbols for different kinds of electrical appliances in an electric circuit for the ease of drawing and understanding. The symbols are shown in table below. Name Symbol 1. Electric cell 2. Battery 3. Electric wire 4. Switch 5. Resistance 6. Ammeter 6. Voltmeter 7. Light bulb

214 There are 2 types of electric circuits as follows: 1. Series circuit In a series circuit, electrical appliances are connected with an electric source. An appliance is directly connected with another appliance to form only one pathway. The disadvantage of a series circuit is that when an appliance breaks down, other appliances in the circuit will not function because the electric current cannot flow. Summary of resistance connected in series 1. Total resistance can be measured by addition, thus the total resistance will increase. 2. The quantity of electric current flowing past each resistance equals electric current in the circuit. 3. The electrical potential difference between the 2 ends of the resistance equals the sum of electrical potential difference of the 2 ends of each resistance. 2. Parallel circuit It is a circuit where different components are separately connected to the electric source, thus consisting of several circuits in the integrated circuit. The advantage of the parallel circuit is the ability to maintain current flow although any of the component breaks down. The connection of 2 light bulbs in which the 2 poles of a light bulb are put across the 2 poles of the other light bulb is called parallel circuit. The current from the electric source flowing inside the circuit will be divided through different electrical appliances in different

215 volumes, depending on the resistance of each appliance. When the electrical appliance has high resistance, electric current is little, and vice versa. The current flowing through each electrical appliance equals the sum of current flowing from the electric source. We use Ohm’s Law to calculate the resistance and amount of current flowing in the circuit for the light bulb connected in parallel. Summary of resistance connected in parallel 1. The total resistance of the circuit decreases and is less than the smallest resistance connected in parallel. 2. The total quantity of circuit current equals the sum of the small electric current. 3. The electrical potential difference between the 2 ends of each resistor is the same, and equals the electrical potential between the 2 ends of resistors connected in parallel. 5. Ohm’s law Electric current can flow in the circuit because electric voltage is distributed to the circuit. The quantity of electric current in the circuit is limited by resistance in such electric circuit. Thus, the quantity of current in the circuit depends on electric voltage and circuit resistance. According Ohm’s Law, the current flowing in the circuit has a direct variation with electric voltage and reverse variation with electrical resistance. The relationship can be drawn as follows: Current = Voltage Resistance Example I=V R Calculate the quantity of current in the electrical circuit with the voltage of 50 volts and resistance of 5 ohms. Method From the formula I=V Substitute value R I = 50V 50 I = 10 amperes

216 Instrument 1. Adjustable direct current power supply of 0.30 V 2. Multimeter 3. 3 resistors of different sizes 4. Electrical wire Experiment 1. Connect the circuit for the resistor of the adjustable direct current power supply as shown in the picture. 2. Adjust the voltage of the power supply 5 times. For each time, current flowing through the circuit must be measured and recorded. 3. Find the intemediate value. 4. Use the value to sketch a graph between V and 1 as in the figure. 5. Find the slope compared with the value obtained in 3 compared with the resistor. Then, repeat steps 1-4. Question Is the value of V obtained in accordance with Ohm’s law? Why? I 6. Electrical wiring There are 2 types of electrical wiring: open wiring and concealed wiring. 6.1 Open wiring For this type of wiring, the wire can be seen and the place may look unorganized, especially if the technician fails to wire up in a perfectly straight line. The advantage of the open wiring is that it is cheaper and can easily be checked and fixed. Step 1 Determine the plugging spots and wiring route. The route should be the same as the

217 old one. If there is already a wire in place, the new wire should follow the existing wiring route before separating to the desired spots. Step 2 For new electric wiring, the wire should be linked from the connecting spot up to the ceiling before returning to the desired spot. Measure the distance from the wall edge and mark the wiring path with a measuring thread. Step 3 Nail down the cable tie along the drawn line on the wall and the new spot. Fold the tie on the nail head for holding while nailing. Step 4 Leave a space of 10-15 centimeters for each cable tie. Around the ceiling curve or corner, the cable ties must be nailed close, leaving a space of 1-2 centimeters between each to fasten the wire tightly to the wall and prevent the wire from bending. Step 5 Install plugs on the new spots, use drills to punch the block and use screws to tighten the block. For a wooden wall, wooden structure should be attached first to strengthen the wall. Step 6 Wire up along the line of nailed cable ties and fasten the wire tightly with the cable ties. Connect the wire with the new plug and with the block. Step 7 Turn off the main switch and use a spark detecting screwdriver to make sure there is no current flowing in the plug to be connected. Then, connect the wire with the same plug and turn on the switch. Use a spark detecting screwdriver to check the current at the new plugging spot. 6.2 Concealed wiring The wire is placed in the conduit hidden in the building wall, making the place orderly and easy to decorate as the wire cannot be seen. The installation of the conduit must be done together with laying and plastering bricks. Do not allow concealed wiring without putting the wire in a conduit as it can be dangerous for the residents in case of electric

218 leakage. The installation is more expensive and complicated than open wiring. Changes and fixing after installation is much more difficult and costly than the first type of wiring. Electrical wiring is usually in the form of open wiring on the building wall while the water pipes are installed on the floor and wall edges. Thus, in case of damage, inspection and repair can easily be carried out. However, in modern households, beautiful outlook has become more important. Thus, concealing electrical wires placed in the conduit inside the wall or above the ceiling becomes more common and the water pipes are installed inside the wall or underground for neat appearance. Although this way of wiring makes the place more orderly and neat, it also has disadvantages. In case of electric shock and electric or water leakage caused by the use of low-quality materials or incorrect installation or damage from use, it is hard to inspect or fix. Ceiling, wall or some areas may need to be disassembled to inspect and fix the problems. This causes damage to the house and costs more time and money. One way to avoid the problem is by using open wiring but it makes the place look unorderly and is good only for small houses. Those who prefer neatness and have a big house requiring wiring in various spots should rely on concealed wiring. However, the use of high-quality, suitable materials as well as proper and systemic wiring can prevent the above problems . Suggestions for designing interior electrical circuit Control circuits in a house should be separated by, for example, floor or type of electrical appliance. With this, fixing will become easier in case of electrical interruption. Electrical circuit of rooms should be separated in order that, if the electricity must be cut off for fixing, the kitchen electricity can be left on so that the food in the refrigerator will not be spoilt. 7. Basics of use of electrical appliance Light - Install an appropriate number of light bulbs for use - Use light bulbs with high illumination, low energy consumption, long useful life, such as fluorescent and compact bulbs. - Regularly clean the light bulbs or lamps.

219 - Paint buildings with light colors for better light reflection and brightness. - Turn off all the light bulbs after use. Fan - Choose the size and design which is suitable for the purpose of use. - Select appropriate speed. - Turn on only when necessary. - Regularly maintain it in a good condition. Television - Choose the size which is appropriate for the family and room area. - Watch only 1 program or turn on a television only when there is a program of interest. - Unplug the television every time after use. Hair dryer - Wipe the hair half dry before using the hair dryer. - Rub and comb the hair during use of the hair dryer. - Blow the hair with hot air as necessary. Electric iron - Do not spray too much water on clothes to be ironed. - Adjust the steaming level to suit the type of clothes. - Start ironing light clothes while the iron heat is still low. - There should be an appropriate amount of clothes for each ironing time.. - Unplug the iron a few minutes before finishing ironing and complete the ironing on stored energy. Coffee-making pot - Fill the pot with an appropriate amount of water. - Close the lid tightly before boiling. - Turn off right after the water boils.

220 Electric rice cooker - Choose the size which is appropriate for the family. - Unplug when the rice is cooked or there is no need to keep the rice warm. Refrigerator - Choose the size which is appropriate for the family. - Locate the refrigerator away from heat. - Do not put food which is still hot in the refrigerator. - Do not put too much food in the refrigerator. - Defrost once a week. - Regularly clean the condenser. - Do not open the refrigerator door too often or leave the door open. - Regularly make sure the door gasket is tightly closed. Heater - Choose the size which is appropriate for the family. - Do not use too high heat level. - The valve should be closed from time to time to keep the water warm during a bath. - Do not use a heater in summer. - Shut the valve and switch off the heater immediately after use. Air-conditioner - The room with air-conditioning should have an insulated ceiling. - Choose the size which is appropriate for the room space. - Choose the air-conditioner which has quality certification and saves energy. - Adjust the temperature and fan to suit each season. - Regularly maintain and clean air-conditioners and their parts to keep them in good condition.

221 - Always make sure doors and windows are tightly closed. - Use the ventilation fan only when necessary. - Turn off air-conditioners a few minutes before you leave the air-conditioned room. Laundry machine - The quantity of clothes should suit the machine capacity. - Dry clothes in the sunlight instead of the cloth dryer. - Study and follow the instruction.manual. 8. Safety and accidents in the electrical professions 1) Before working on electrical appliances, you should check or measure whether there is current in the appliance, using an electric current meter. 2) For operations using electrical appliances while the switch is off or the electricity is cut off, the appliance wire must be grounded before and throughout the work. 3) For grounding, you must always start from the ground end before connecting the other end with the electrical appliances. 4) Before touching any low-voltage electrical appliances, you should use the electric current meter to check the current. 5) The correct tools, equipment and procedures must be adopted when touching electrical appliances. 6) The tools or equipment used with electrical appliances, such as pliers or screwdrivers must have double insulation. 7) While working, make sure no parts of the body or the tools in use touch other electronic devices. 8) The use of a key to prevent switching as well as hanging of a sign which prohibits switching operation and release of the key and sign must be carried out by the same person. 9) When performing electrical work at a high spot, use a safety belt. If it is not available, tie a big rope with the structure or part of the building to support the body.

222 10) When performing electrical works, you should always be accompanied by an assistant. 8.1 Cautions for general electrical work - Switch covers or boxes which are damaged should be changed and fixed promptly. - Keep the area close to the switch clean. - Regularly inspect the switchboard and the control board to make sure there is no scraps of copper or conductive metal. Do not remove any devices such as fuses from the control board. - Use a fuse which is suitable for each task. Before changing a fuse, make sure the switch is in the correct position (to keep the electric circuit open). - Do not use a switch cover made of flammable materials. Keep the switch cover open. - Each switch should be attached with a label consisting of the following details: * Type of current: Use with direct or alternating current * Electrical potential difference (or electric voltage/electromotive force) * Voltage * Electric devices connected with the switch * Recipient name - Switch off to open the electric circuit before inspecting or fixing a machine. The sign or label “under repair” should be placed on the switch. Before switching on, make sure every process is done and you have received the signal to proceed. Also, before starting the machine, inspect the machine to make sure there is no object stuck in it. - On and off signals must be communicated cautiously. - Do not switch off ‟ on while the hand is wet. - Make sure the signal for closing the circuit is correctly understood before switching on. - Tightly screw bolts to fasten the electrical wire. - Do not use damaged electrical devices as they are dangerous. 8.2 Don’ts for electrical works - Do not unplug by pulling the wire hard. - Do not use damaged electrical devices or equipment. - Do not use damaged plugs.

223 - Do not use excessive electric power. - Do not connect wrong types of plugs. - Do not fix electrical appliances by yourself unless you possess adequate relevant knowlege. 8.3 Safety for electrical workers Outfit - The appropriate outfit for machine-related work is an overall in a good condition. Wearing torn outfits while fixing a machine is dangerous as they may be stuck in the operating machine. - Fasten all buttons. - Do not wear accessories such as necklaces, watches or rings. - Wear brogans or boots to protect yourself from sharp metal scraps. - Wear eyeglasses to protect your eyes from metal scraps when doing polishing work or from light when doing welding tasks. - Wear a helmet. - Do not grow long hair or you should wear a helmet. - Under a loud environment, wear an earmuff. Safety helmet Belt Rubber gloves Leather gloves Safety line Boots

224 9. Management and service excellence Service excellence is a result of willingness and efforts to provide quality services to the client. Level 1 Willingly provide services to the client o Provide friendly services. o Give correct and clear information to clients. o Inform clients about the progress of issues or processes of works being served. o Coordinate with clients consistently and quickly. Level 2 Help solve the client’s problems o Help solve problems quickly and willingly. Do not make excuses or blame others. o Make sure clients are satisfied with the service. Learn from the problems to further improve services. Level 3 Provide good services which exceed expectation and go extra miles o Give extra time to clients to successfully solve their problems. o Recommend options which best benefits clients. Level 4 Understand and provide services to serve the real needs of clients o Try to understand clients so that you can provide services which meet their real needs. o Give useful suggestions to answer their needs. Level 5 Provide services which are truly beneficial to clients o Take into account long-term advantages of clients. o Act as a consultant who takes part in the clients’ decision making. o Offer opinions and suggestions which may be different from what clients expect but are more suitable for their needs, problems and cases for the clients’ best benefits.

225 10. Scientific project for the profession Being an electrician is an important profession for the technological world. Electrical workers must have expertise, be creative, and do works other than installation and repair. In addition, they should invent electrical appliances for homes which bring more convenience and comfort to our daily life. So, works of electricians are not limited only to electrical service but also include developing products for commercial purposes. Learners can apply the knowledge and works gained from electrical projects to their profession such as for, creating decorative lamps, reading lamps, simple flood warning devices, etc. Example 1 Creating a decorative lamp Materials about 30 baht 1. A light switch about 79 baht 2. A long fluorescent light bulb reused 3. 61 CDs about 30 baht 4. 1.8-meter-long wire How to make a lamp from CDs Who would think that used CDs can be used to make a beautiful luxury lamp? Let’s find out how we can make such a beautiful lamp, at the cost of 139 baht.

226 Bulb for this project. Disassemble the light bulb components. Take out the switch and bulb, and attach them on the outer area of the box. Position the switch and the light bulb.

227 Cut 18 pieces of 3/8-inch thick veneers in a circle shape, the size of a CD. The cut veneers. Apply super glue on the veneers and tighten them with screws Leave them to dry for 20 minutes.

228 Drill a hole in the middle for putting the bulb. Also drill a hole for the wire and switch. Put the light bulb inside the hole.

229 Place the switch and wire in their places. Drill a hole in the middle of the CD, wide enough for the bulb. Insert the bulb as shown in the picture.

230 Attach a pair of CDs, turning the shiny side out. Then, apply super glue and leave it to dry. After that, drill 3 holes for inserting long nuts so that they may act as the legs like in the picture. Put only 1 CD on the first layer. Then, insert rings to support. Each layer has some space for the light to shine. Keep putting CDs. On the last layer, glue 4 CDs together to cover the top. To check the light bulb, unscrew the nuts and change the bulb. The finished lamp with the light on is as shown in the picture. Source: http://www.yousaytoo.com/tensionnot/how-to-make-a-cool-cd-lamp/4877

231 Example 2 Simple flood warning device Materials 1. A switch and a wireless electric bell of about 100-150 baht 2. Foam scrap reused 3. A plastic bag reused Procedures 1. Buy a wireless door bell which can be found at any department store (the prices range between a little over 100 baht ‟ 500 baht). A bell which rings continually should be used as it can wake you up if you are asleep. (Some bells ring only once despite a long push). 2. Find these materials ‟ short basket, foam, waterproof zipped plastic bag, duct tape, double-sided tape, a brick or rock. 3. Put the double-sided tape on the small bell (bell switch) on the push button to make it higher (do not peel off the other side). Then put it in the waterproof zipped plastic bag.

232 4. Cut the foam into a size which is a little smaller than the basket. Put the zipped plastic bag containing the small bell in the middle of the foam. Connect them with a tape. 5. Find an appropriate spot to place the foam on the ground where the flood warning device is needed, such as the gate. Cover the foam with the basket. Put a brick or rock on the basket (the signal distance is about 100 meters from the main bell). 6. Plug in the main bell inside the house. 7. When the area is flooded, the foam will float and the bell switch will be pressed against the basket which has a brick or rock on its top. Thus, the alarm will ring.

233 Source: http://www.oknation.net/blog/print.php?id=653105 11. Electrical terms Electricians must understand electrical terms commonly used in order to efficiently order supplies and materials as well as read equipment specifications given by manufacturers. The person who orders products and the reader must be familiar with the electrical terms. Therefore, it is important to carefully study the definition of each technical term and always refer to the technical term handbooks where appropriate. Additional details of the definitions of these technical terms are available in the last part of this book. Energy: The ability to do work. Horsepower: The measuring unit of motors and engines. It is usually abbreviated as HP or hp. Horsepower indicates the output of an electrical motor. Electricity: The flow of electrons through a conductor. Conductor: The matter allowing electric current to easily flow through. Conductance: The ease of flow of electric current in the circuit. Insulator: An object with the electric current resistance property. Such matter obstructs the flow of electrons. Magnetism : The property of attracting certain metals. Polarity : The state of having either a positive or negative electric charge. Electromagnet : A piece of metal that becomes magnetic when charged with an electric current. Primary winding : A coil of an electric transformer connected with a power supply and taking in energy. It is the electricity input side of the transformer.

234 Secondary winding : A coil of an electric transformer which is connected with load (electrical load) and takes in energy using electromagnetic induction from the primary winding to the load. It is the electricity output side of the transformer. Electric power: The rate of electric energy production or use at a time unit. Watt : A unit for measuring electric power. Its abbreviation is “W”. Electric power represents the power in each electrical appliance for use such as a 1,000-watt light bulb and a 1,000-watt toaster. Kilowatt : A unit for measuring electrical power, equal to 1000 watts. Its abbreviation is KW. In practice, when there is a lot of load or electrical load, the watt is high. The unit iof watt is very small and is too long for communication and data recording. So, the unit of kilowatt which is a larger unit is used more commonly. There is also a unit larger than kilowatt, called megawatt, which is equal to 1,000 kilowatts. It is used as 1 MW for short. Kilowatt-hour : A unit for measuring electrical power, equal to the amount of work produced by 1 kilowatt in an hour. Its abbreviation is KWH. Normally, household use of electric power can be measured by an electric meter. Its measuring unit is kilowatt-hour or unit. The electricity fee is calculated by multiplying the number of units used with electricity charge per unit. Alternating current: An electric system with reversing directions of the flow of electric charge. We use “AC” as its abbreviation. It is commonly used in households, buildings and factories. Direct current: The electric current which flows in a constant direction. It is commonly used in batteries and dry batteries. We use “DC” as its abbreviation. Circuit : A connected electrical path where electric currents flow through. Series circuit: A circuit with only 1 electric path from the electric source and current flows directly through to the other end of the electric source. In this kind of circuit, devices such as fuse, switch or circuit breaker may be connected in series to protect and control the circuit. Parallel circuit: A circuit with more than 1 electric path in which light bulbs and plugs are connected in parallel. Unlike the series circuit, the advantage of this circuit is the ability to maintain current flow even when a component breaks down as illustrated in the picture.

235 Electric source Parallel circuit Open circuit: A circumstance where the formal path of current is disconnected or intervened, resulting in no current flow. Short circuit : A circumstance of electric short when there is an abnormal connection between 2 nodes of an electric circuit, resulting in electric leakage. Ampere: The unit of electric current flowing through the conductor. It is abbreviated as “A” or “amp”. Normally, this unit is used for determining the maximum electric current which is still safe for the use of each electrical appliance such as 15-amp plug or 30-amp fuse. Hertz: A unit measuring frequency. It is defined as the number of cycles per second of a periodic phenomenon. An electron flows in a direction and returns to the electric source, and another electron flows from the electric source to another direction and returns. A cycle occurs when 2 electrons flow in opposite directions (in other words, they have alternating flows). The frequency of the household electric system is 50 hertz. Hertz is abbreviated as “HZ”. Ohm: The unit of electrical resistance using “Ω” as its symbol. Resistance can both support and obstruct electrical flow. It works while it is used as an insulator or used for controlling the circuit. For example, wire tape or plastic plugs can help prevent danger for the electricity user. Also, rheostat can be used to adjust brightness of the light bulb, but it obstructs the user’s work if the user uses a small and very long wire or there is rust on the conductor. These increase resistance, causing overheat and loss of electric power in the conductor wire. Ohm’s law: The law of the relationship between voltage, current and resistance in an electric circuit. This rule says that the electric current (I) has a direct variation with voltage (E) and has a reverse variation with resistance (R). The formula is I = E/R.

236 Volt: The unit of voltage, electric potential difference or electromotive force. “V”, “E” or “EMF” are used as the abbreviations. Normally, “E” and “EMF” are used for voltage from electromotive force (which is another definition of volt), The same as ampere, voltage specified on the electrical appliance determines the maximum voltage for a safe use, such as 220-volt motor or 110-volt hairdryer. We should use electrical appliances and voltage according to what is specified only. Ammeter: A measuring instrument used to measure the electric current in a circuit. Usually, we connect this device in series with the circuit. However, there are some special devices which are not required to connect to the electric circuit. They will be discussed in the following lesson. Ohm meter: An electrical instrument that measures electrical resistance. During use, no electricity must be distributed from any electric sources in the circuit. Volt meter: An instrument used for measuring electrical potential difference between 2 points in an electric circuit. Multimeter: An electronic measuring instrument which can measure electrical potential difference, current and resistance. National Electric Code : A manual of rules and regulations for safe installation of electrical appliances. Although it is rich in content, it does not aim for teaching or use by those without training. In Thailand, this type of manual can be found in many places, such as those of Metropolitan Electricity Authority, National Energy, or Provincial Electricity Authority. Most of the principles and regulations are similar to that of the NEC (National Electric Code). Circuit breaker: An automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload. When there is overload, the circuit breaker will open the circuit to prevent the flow of current into the circuit before switching on again. At present, it is commonly used instead of fuses as it can be reset automatically while a fuse needs to be replaced. Especially for the three-phase electrical system, if a fuse breaks and electricity flows through only 2 phases, damage might occur with the three- phase motor. A circuit breaker works under the principle of magnetic field. When there is a lot of current, the magnetic field will switch off automatically. In addition, for certain types, the overload prevention device is connected under the bimetallic principle. (Bimetallic is a

237 metal which extends when the temperature is higher and shrinks when the temperature is lower). When there is a lot of current, the heat coming out will cause the bimetallic to expand and switch off. We use “CB” as the abbreviation for the circuit breaker. Fuse: A device to provide overcurrent protection. Its essential component is a metal wire that melts when too much current flows, which interrupts the circuit. A fuse must be connected in series with the circuit. Transformer: A device that transforms the potential difference to become higher or lower to suit each electrical appliance. For instance, when there is a 110-volt washing machine, but the electricity has a voltage of 220 volts, we need to use the transformer to transform 220 volts to 110 volts to be able to use the washing machine. Moreover, we usually use a transformer for internal communicative devices and bell system, etc. Phase: An electric system which consists of 1 phase 2 wires, and 3 phases 4 wires. The 1 phase 2 wires type of electrical appliances is used in households while the 3 phases 4 wires type is used for large businesses and industrial factories.

238 Bibliography Electricity Generating Authority of Thailand. (2008). Electrical system and surface-mounted wiring for home. Bangkok. ------------. (2008). Electrical system and surface-mounted wiring with conduit. Bangkok. Chinda Phattharap and Atchariya Thongpong. (2008). Learning media and essence for sciences subject for lower secondary level, Office of the Non-Formal and Informal Education. 3rd edition, Bangkok. Pages 221-223. Bancha Saenthawi, et al. (2007). Learning media of Office of the Non-Formal and Informal Education, sciences subject (SC 20) for lower secondary level. Watana Panich Company Limited, Bangkok. Page 241. Sarawut Yanyut. (2004). Handbook on basic knowledge for the third group of lower secondary level, techinician profession and technology. MAC Publishing Limied. Pages 59-62. Office of the Non-Formal and Informal Education. (2004). Distance learning, profession development category (Code: PorOr 20) for lower secondary level. Printing house of the Express Transportation Organization of Thailand, Bangkok. Pages 70 and 79 ‟ 81. ------------. (2010). Handbook on basic knowledge for the sciences subject (PorWor. 11001), Non-formal Education Basic Curriculum of B.E. 2551. 1st Edition of 2010. Akepimthai Company Limited. Bangkok. Pages 159-160. Suchat Wongsuwan (2003). Learning for 21st century: constructionism, a project document for the workshop on integrated learning. Hatyaiwittayalaisomboonkulkanya School, Songkhla.

239 Appendix 1. Ways to develop scientific potential for professions Having a profession is very important to human lives. A profession does not only respond to the economic need of human beings, but provides also for other needs such as social and mental needs. Thus, the selection of a profession is important for individuals. If we choose a suitable job, we are likely to have a successful work life. On the contrary, if we choose an inappropriate profession, there is a high possibility of professional failure. There are 5 professional curriculums as follows: Table: Analysis of scientific potential development for professions Profession Characteristics Content Related professions category 1. Agriculture 1. Agriculture means 1. Scientific processes 1.Livestock Example: Livestock and growing crops, such as and application of large-scale farming professions such as raising rice farming, orchard knowledge about of native chickens, pigs, beef cattle, milk cows, farming and crop farming. scientific processes and bees, goats, frogs, raising mussels on ropes, oysters, 2. Livestock means land scientific projects as well sericulture, groupers in baskets, catfish, carps, animal farming, such as as technology and daily Muscovy ducks, etc. 2. Crop and orchard cows, pigs or fowls, etc. life. farming. 3. Rice farming. 3. Fishery means 2. Living things and the Example: Crop and orchard farming includes aquaculture such as environment, sugarcane farming, finger root farming, pomelo raising fish and fishing. classification of living 4. Forestry means forest- things, ecological related professions such systems, natural as planting economic resources, environment, plants, processing wild local wisdom products, etc. conservation, and biotechnology. 3. Energy in daily life and energy conservation.

240 Profession Characteristics Content Related professions category 4. Astronomy for life, orchard, mango orchard, 2. Industry relationship between the mangosteen orchard, Sun, the Earth and the durian orchard, jasmine Moon and related orchard, flower garden, phenomena. decorative plant garden, home-grown vegetables, etc. 1. Technicians in agro- 1. Scientific processes 1. Product manufacturing, industry such as milk cow and application of product processing, and farm, hydroponics, knowledge about household industry or canned longan in syrup scientific processes and handicraft. manufacturing plant, and scientific projects, and 2. Parts and electrical agricultural produce technology and daily life. appliance manufacturing processing industries. 2. Living things and the and maintenance. 2. Technicians in factories environment. 3. Household product manufacturing finished Classification of living manufacturing such as products such as things, ecological vegetable oil and palm oil. electrical appliances systems, natural 4. Bedding and fabric doll factories, furniture resources, the manufacturing. factories and bicycle environment, local 5. Manufacturing of plastic factories. wisdom conservation, and products, detergent and 3. Technicians in factories biotechnology. water bottles producing raw materials 3. Substance for life, 6. Certain works in the such as crepe rubber elements, chemical manufacturing process. factories and palm oil compounds and Example: Household factories. solutions, substances and industrial product 4. Technicians in products in daily life, manufacturing such as factories manufacturing synthetic substances, Teenchok, Madmi and silk industrial goods such as impact of substances and weaving, basketry works,

241 Profession Characteristics Content Related professions category synthetic fiber factories products on the weaving, mat weaving, 3. Commerce and hot-rolled and cold- environment. canvass sewing, sheet rolled steel factories. 4. Force and energy for rubber production, T-shirt 5. Technicians in the life, energy conservation production, batik making, petroleum industry such and alternative energy. hair accessories making, as petroleum exploration producing items from and drilling, petroleum mulberry papers, refineries for producing producing souvenirs, different types of oil. making garlands, making 6. Technicians in finished clothes, making machinery factories such charcoal, making as compressor factories, Northeastern-style air-condition factories, sausages and Chinese water pump factories, steamed dumplings. small engine factories and motorcycle assembling 1. Trading of products and factories. bookkeeping services 7. Technicians in the 2. Services automobile industry such Cooking, selling souvenirs, as car assembling local products,selling factories and car body noodles, selling food, assembling factories sundry goods, groceries, It involves trading and 1. Scientific processes management related to all and application of kinds of trading, including knowledge about retail trade, wholesale scientific processes and trade, export, banking, scientific projects, and insurance, and artificial technology and daily life. intelligence in computers 2. Living things and the

242 Profession Characteristics Content Related professions category for commercial purpose. environment, finished products, desserts, 4. Creativity classification of living fruit, food and beverages, Creative professions such things, ecological lottery, dolls, deep-fried as systems, natural dough stick and fresh sea- 1) Heritage or cultural resources, the food. heritage involves history, environment and 3. Act as a trading archeology, culture, conservation. middleman such as a tradition, belief and social 3. Energy in daily life and commission merchant, condition which can be energy conservation. customer care staff as well classified into 2 groups: 4. Technology. as selling pets, air tickets, 1. Traditional cultural or furniture. expressions such as 1. Scientific processes 4. Selling medical supplies, and application of medicine, cosmetics, silver knowledge about accessories, gold scientific processes and ornaments, fresh flowers, scientific projects, and cooking gas, cosmetic technology and daily life. direct sale, agricultural 2. Living things and the produces, hand-made environment, industrial products, etc. classification of living It is classified into 9 groups things, ecological as follows: 1) Crafts 2) Designs 3) Fashions 4) Films and videos 5) Broadcasting 6) Performing arts 7) Advertising 8) Publishing

243 Profession Characteristics Content Related professions category crafts, festivals and systems, natural 9) Architecture celebrations; and resources,the 2) Cultural sites such as environment and historical sites, museums, conservation. libraries, and exhibitions. 3. Substance for life, 2) Arts is a creative elements, chemical industry related to arts compounds and and culture and can be solutions, substances and classified into 2 groups: products in daily life, 1. Visual arts such as synthetic substances, paintings, photographs, impact of substances and and antique objects; and products on the 2. Performing arts such as environment. musical shows, plays, 4. Force and energy for dances, operas, animal life, energy conservation shows, and puppets. and alternative energy. 3) Media is related to the 5. Energy in daily life and production of creative energy conservation works to communicate with a large number of people and can be classified into 2 groups: 1. Publishing and printed media such as books, newspapers, and other printed materials; and 2) Audiovisual media such as TV dramas, radios and other kinds of

244 Profession Characteristics Content Related professions category broadcasting. 5. Management and services 4) Functional creation is the group of products and services which satisfy different needs of customers which can be classified into 3 groups: 1) Designs such as interior designs, graphics designs, fashion designs, jewel designs and toy designs; 2) New media such as software, video games and digital content; and 3) Creative services such as architecture, advertising, culture and recreation, research and development, and other digital and other creativity-related services. In the services sector, 1. Scientific processes, Example: Repair services, operators sell services to application of knowledge such as motorcycle and car facilitate the convenience about scientific processes mechanics, auto body and of service buyers or and scientific projects, painting technicians, car customers. Service quality and technology and daily seat repair technicians, TV is measured by customer life. and radio repair satisfaction. Income is the 2. Living things and the technicians, electrical

245 Profession Characteristics Content Related professions category service fee. This type of environment, appliance repair profession does not require high capital classification of living technicians, welders, investment compared to product manufacturing, things, ecological aluminum roof making and processes are not so complicated. However, systems, natural technicians. service providers must possess professional resources, the Beauty business such as knowledge, ability, experience or expertise. environment and tailors, beauty operators, conservation. make-up artists, facial 3. Substance for life, masseuses, hairdressers, elements, chemical artists, portrait painters, compounds and advertising poster artists, solutions, substances and construction workers, fresh products in daily life, and dry flower arrangement synthetic substances, artists. impact of substances and General services such as products on the babysitting, laundry environment. services, video rental, book 4. Force and energy for rental, bungalow rental, life. energy conservation apartment rental, beach and alternative energy, scooter rental, car rental, electric energy, light taxi service, motorbike taxi energy, sound energy, service, cross-village energy in daily life and public carriers, tricycle taxi energy conservation service, photocopy service, report typing service, musicians at restaurants, oyster shucking, lemongrass chopping and construction contractors.

246 Bibliography National Science and Development Agency. 2006. Lab technique manual. Bangkok : Rukluke Family Group Limited. Ekarin Simahasan, et al. Sciences for Grade 6.Bangkok: Aksorn Charoen Tat ACT. Co., Ltd. http://www.nc.ac.th/WEB%20E_BOOK/unit1_4_4.htm http://my.thaimail.com/mywebboard/readmess.php3?user=mr.neo&idroom=2&idforum=45&l ogin=&keygen=&nick= http://www.panyathai.or.th/wiki/index.php http://www.school.net.th/library/create-web/10000/science/10000-6250.html http://www.maceducation.com/e-knowledge/2412212100/16.htm http://th.wikipedia.org/wiki http://gotoknow.org/file/chiew-buncha/salt_farm.jpg http://media.photobucket.com/image/ http://www.thaitambon.com/thailand/Trat/230103/0683184742/FB849_1674A.jpg http://www.boatbook.co.th/prdimg/600-6075.jpg http://www.bloggang.com/data/oordt/picture/1228099928.jpg http://www.thaidbmarket.com/uploads/20090309-130917-.jpg http://www.siamonlineshop.com/picpost/Qshow51637.jpg http://www.thaitarad.com/shop/kaisong/images/product/711996b4c4e3881b5dd42c07395c c02e.jpg http://www.lancome-th.com/upload/product/thumbnail/pm-299-5421.jpg http://www.igetweb.com/www/shoppergirl/catalog/p_32791.jpg http://www.panyathai.or.th/wiki/index.php http://www.dbh2008.com/lesson/show.php?id=21

247 Textbook Development Team Advisors 1. Mr.Prasert Boonruang Secretary-General, Office of the Non - Formal and Informal Education 2. Mr. Chaiyos Imsuwan Deputy Secretary-General, Office of the Non - Formal and Informal Education 3. Mr. Watcharin Jumpee Deputy Secretary-General, Office of the Non - Formal and Informal Education 4. Mrs. Watanee Chanokul Specialist in Learning and Techning Material Development 5. Mrs. Chuliphon Phatininnat Specialist in Educational Technology Media Promotion 6. Mrs. Anchalee Thamwithikun Head of Supervisory Unit 7. Mrs. Suthinee Ngamkhet Director, Non-Formal Education Development Division Authors and rewriters King Mongkut Memorial Park of Science and 1. Mr. Sa-ngat Praditsuwan Technology at Waghor, Prachuap Kiri Khan Samutsakhon Science Center for Eduction 2. Mr. Prakit Jansri Ayutthaya Science Center for Eduction 3. Mr. Suchat Malakan Trang Science Center for Eduction 4. Mr. Chaikit Anuntaniruttisai Editorial and revision team King Mongkut Memorial Park of Science and 1. Mr. Sa-ngat Praditsuwan Technology at Waghor, Prachuap Kiri Khan Samutsakhon Science Center for Eduction 2. Mr. Prakit Jansri Ayutthaya Science Center for Eduction 3. Mr. Suchat Malakan Trang Science Center for Eduction 4. Mr. Chaikit Anuntaniruttisai Retired official 5. Mrs. Thanyawadi Laophanit Retired official 6. Miss Chanita Chittham

248 Working team Non-Formal Education Development Division 1. Mr. Suraphong Manmano Non-Formal Education Development Division 2. Mr. Supphachok Sirattanasilp Non-Formal Education Development Division 3. Miss Wannaphon Patthamanon Non-Formal Education Development Division 4. Miss Sarinya Kunpradit Non-Formal Education Development Division 5. Miss Phetcharin Lueangchitwatthana Editorial and revision team, 2nd Edition Director, King Mongkut Memorial Park of Science and Technology at Waghor, Prachuap Kiri Khan 1. Mr. Sa-ngat Praditsuwan Deputy Director, Nakhonratchasima Science Center for Eduction 2. Mr. Manot Lapchit UbonratchathaniScience Center for Eduction Teacher of Special Expertise, Khon Kaen Science 3. Mrs. Chansi Atsupho Center for Eduction 4. Mrs. Natthaphon Manuprasoet Teacher of Special Expertise, Samutsakhon Science Center for Eduction 5. Mrs. Anathika Khotchaseni Educator of Special Expertise, Non-Formal Education Development Division 6. Mr. Chaiphat Phanwattanasakun