Electricity:

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Electricity:. Using electricity. In 1771, Luigi Galvani discovered that the muscles of dead frogs twitched when struck by a spark May have inspired the idea behind the story Frankenstein. How do we get Electricity?. How to generate electricity. - PowerPoint PPT Presentation

Transcript of Electricity:

  • In 1771, Luigi Galvani discovered that the muscles of dead frogs twitched when struck by a spark May have inspired the idea behind the story Frankenstein

  • Generation of Electricity = [Coil of Wire] + [Magnetism] + [Relative Motion]

  • The basic components are:Power Plant: Electricity is produced herePower Grid: A network that connects power plants to substations and substation to homes. Transmission Substation: Transformers increase voltage so that volts can be sent over long distances. Distribution Substation: Transformers reduce voltage to a level suitable for the surrounding community Distribution System: Delivers electricity to homes and businesses. Line may be a underground or overhead. Service Connection: Connection of customers to the grid. A meter is connected also to measure the amount of electricity used by customers

  • When you switch something on, you complete a pathway for electricity to flow through. The pathway that allows electrical energy to flow is called an electric circuit. Electric circuits consist of three components:A Power Supply: Provides electrical energyA Load: Converts electrical energy into another formA Conducting Path: Allows electric charge to flow around the circuit.

  • Electric circuits consist of three components:A Power Supply: Provides electrical energyA Load: Converts electrical energy into another formA Conducting Path: Allows electric charge to flow around the circuit.

  • LoadPower SupplyConducting Path

  • ===

  • Current measures the amount of charge flowing through a circuit .A large current has more charge flowing every second than a small current.

  • Current is measured in a unit called ampere (A) or ampsMilliamps (mA) are used to measure small currents. Current can be measured using a device called an ammeter. Ammeters need to be inserted into the circuit to get a reading.

  • Voltage is measure in Volts (V) A device that measures the amount of volts passing through a circuit is called a voltmeter

  • Voltage is a measure of the amount of energy there is to push charge through a circuit. Voltage is supplied by batteries, power packs and power points.

  • Batteries, power packs or power points are all considered energy sources. They provide all the electric energy and voltage to a circuit. Energy sources create an electric field that pushes electrons around a circuit.

  • Power points supply approximately 240 volts into your home Power packs like the ones we use in class supply up to 12 volts The power for which is produced in a variety of power plants.

  • Batteries are used when we need portable energy sources. 1 AA battery provides 1.5 volts While car batteries provide 12 volts Batteries are made up of cells. These cells can be either wet or dry.

  • In this wet cell, zinc reacts with the acid and releases electrons. If a circuit is connected to the plates then the electrons will flow to the copper plateAs they flow through the circuit the globe will light. Wet cells are usually large and heavy and can leak acid if tipped over.

  • A car battery is a collection of wet cells. The wet substance is sulfuric acid The plates are made of lead and lead oxide. While a car is running it reverses the chemical reaction recharging the battery. Eventually chemicals build up on the plate and the batter dies.

  • Being large and heavy wet cells are useless for small devices like:IpodsLaptopsRemotesThey use small portable cells called dry cells. Dry cells contain a chemical paste and their electrodes are designed to save space. It is common that several batteries are connected together to supply more voltage.=4.5 volts

  • A photovoltaic cell (or solar )is made up of two layers. These two layers are semiconductors.

    When sunlight strikes the top layer electrons are given energy to move to the bottom layer. This creates an electric current.

  • Aka the electric eel Actually a freshwater fish.It can produce up to 600 volts This is five times the amount found in an electrical outlet Uses the electric field to stun fish and to see

  • http://wsc.pv.unsw.edu.au/

    This website allows you to build and name a virtual solar powered car You are then able to race it against computer generated cars.

  • The important feature of this game is the design process. You have a limited budget of $240,000 to build your car.You need to decide on what balance of components are important for speed and power.

  • A conductor is a substance that allows current to flow through it easily.Examples are metals like:Copper: used commonly in electric circuits Aluminium: More expensive, used when copper is unsuitable.

  • Materials that do not allow current to pass through them are called Insulators. Examples of insulators: Plastic Rubber

  • Brief research assignment. What are superconductors ? What uses are there for superconductors? Briefly describe how they work.

    Useful links:http://superconductors.org/INdex.htmhttp://science.howstuffworks.com/question610.htm

  • All metals conduct electricity, but some do so better than others. Tungsten and nichrome for example are not very good at conducting electricity. Therefore electricity flows easier in copper wires than in tungsten. This is called resistance.

  • Resistance converts electrical energy into heat and light. This is used in light globes with tungsten filaments. Conductors have a low resistanceInsulators have a high resistance

  • Without any resistance (such as a globe or heating element) too much current can flow through a circuit. This may generate too much heat in connecting wires or the energy source. This might damage the circuit causing it to melt or catch fire!This is known as a Short Circuit

  • If two globes are arranged in a single line then they are said to be in series. Although the current is said to each globe is the same, the voltage is shared between the two. This means that the globes will both glow more dimly. If one of the bulbs is removed or blows then the other globes in the circuit will not light up.

  • If two globes are arranged in separate branches of a circuit then the are said to be in parallel. Each globe has the same amount of energy and voltage supplied to them . The current is divided between them, This means that they will glow with the same brightness Also if one globe is removed from this circuit the other will still remain lit.

  • SERIES PARALLEL A series circuit arranged of 20 lights would share 240 volts from a power point.Therefore each globe receives 12 volts.

    Disadvantages: If one globes broke then all the other globes with also go out This would make it difficult to find the bad globe. In a parallel circuit all lights are powered by a low voltage source. A transformer reduces the voltage from 240 volts to 12 volts. All globes receive 12 volts.

    Advantages: If one globes breaks all the other globes still have power. This makes it easier to find the broken globe.

  • Type of CircuitVoltageCurrentSeries Split NormalParallelNormal Split

  • Circuits can be combinations of series and parallel sections. Current will always take the easiest way through a circuit. A section with a single globe will be easier to travel on than a section with two. Also it will carry twice as much current.

  • Electrical wiring within you house is one big parallel circuit Electrical companies supply 240 volts to your house.Each power point creates an extra parallel section that receives the same 240 volts.

  • Direct Current (DC)When the current flows in only one direction.An example of this is a battery. Alternating Current (AC) Current flows backwards and forwards. Energy is supplied to houses like this because it is easier to generate and transmit.

  • Short circuits occur when an easier path for current is created. A huge current flows through causing the circuit to overheat and melt. You could even become part of the circuit and be shocked or electrocuted!To prevent this home circuits have fuses or circuit breakers. What's wrong here?

  • A fuse is a thin metal wire, that breaks when too much current passes through it. Fuses are rated according to the amount of current that causes them to melt. Therefore a 5 amp fuse will melt at a current of 5 or more amps.

  • Fuses used to be the most common method for protecting circuits within a house. These days new houses are built with circuit breakers instead. Circuit breakers are special switches that trip (turn off) the circuit if too much current flows through.

  • Electric shock and electrocution (death by electricity) will occur if current finds a path through the body. Only a small current can cause death. The current damages your tissues and interferes with the electric signals that drive the heart and the brain.

  • Step 1: Climb electrical pole.Step 2: Reach out and touch high voltage conductor. Step 3: 16,000 volt Human fireball!

  • If you find someone who has collapsed from an electric shock:Call OOO Switch off main power (if possible)Do not touch the person (otherwise you will get shocked)You may be able to move the person if you use an insulating material (plastic rope, garden hose)

  • The electric chair was invented to replace hanging as a method of execution. It was intended to be a quick and painless alternative In the first ever electric chair execution 1000 volts were applied. This burnt skin and burst blood vessels It still took another 70 seconds at 1300 volts to kill the prisoner. Other prisoners convulsed so violently they broke their own arms and legs. So really its not all that quick and painless !

  • Tour Guide Robot - ToyotaGeminoid HI-1 -Hiroshi Ishiguro Asimo - Honda

  • ASIMO stands for Advanced Step in Innovative Mobility ASIMO is a humanoid robot created by Honda motor company. Height: 130 cm Weight: 54 KgBy the end of 2007 there were only 46 ASIMO robots in existence.

    Further Information:http://world.honda.com/ASIMO/

  • ASIMO evolution ASIMO has been in the making for 20 years In the picture above you can see the current ASIMO compared to its previous versions

  • Geminoid HI-1is a robotic replica of Professor Hiroshi Ishiguro. Professor Ishiguro can operate Geminoid from a distance. This allows him to give two lectures simultaneously at universities that are Kms apart. Further Resources:http://www.irc.atr.jp/Geminoid/overview.html

  • Research a REAL robotCreate a presentation for the entire classThe selection of the robot is up to you The form of the presentation is also up to youOr make a Timeline of Robot development

  • Individually you are to design a robot to fulfil a specific function. You must include a design of your robot with labelling to explain why each section is essential to its function. You must also create a short comic strip that demonstrates your robot in action.

    *This would make them useless for things like ipods, tv remotes etc (ask students a question in regards to this) ***