Electricity Simulation: Electricity · Electricity Simulation: Electricity . Activity One ....

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Electricity Simulation: Electricity Activity One Introduction Understanding electricity requires understanding the terms used. It also requires some mathematical reasoning. Let's start with the volt. This is the SI (International System) unit of measurement for electric potential. Named for the Italian physicist Volta, who invented the first electric cell and an electrostatic generator, the symbol for volt is V. Batteries, solar cells, and generators are all voltage sources. A 9-volt battery has the potential to make a Walkman or clock work. But until it is connected, nothing happens. When connected with metal wires to a circuit, volts cause electric currents. Currents are the flow of electrical charges through a metal wire. Electric current is measured in amperes. The SI symbol for amperes is A, but it is commonly abbreviated as "amp." Higher voltage can produce more current. However, there is one more factor that determines how much current will flow through a circuit-- resistance. Resistance comes from the wire and from the "load" connected to the wire. A relationship called Ohm's law states that the amount of current is always directly proportional to the available volts: I=V/R (physics formulas use I for current). The load is the object using the electrical energy. This object transforms electricity into more visible forms of energy-- light, heat, sound, or movement. These objects are rated in watts, which indicates how much energy it will use. Once a circuit has been set up, the voltage and resistance will be constant. The current is "pulled" or used based on the watts of the "load." A 60-watt bulb will pull more current than a 35-watt bulb. A refrigerator will pull more current than a computer. An ammeter will show the relative amount of current used by each. Directions Use the Electricity Generator simulation to observe and compare the relative amps used by light bulbs that have different watts. Procedures 1. Click on the Start Here button and read the text. If you need more information, click and read the Background. Close the window when you are done. 2. From the pull-down menu under Strength of Magnet, select Large. Under Number of Turns of Coil in Wire, select Many. Under Speed to Crank Generator, select Fast. These choices create an electricity generator. 3. The variables that test the current are How To Wire Light Bulb and Wattage Of Light Bulb. Start with 1 bulb and a light bulb that is 35 watts. Click on the Start Generator button.

Transcript of Electricity Simulation: Electricity · Electricity Simulation: Electricity . Activity One ....

Electricity Simulation: Electricity Activity One

Introduction Understanding electricity requires understanding the terms used. It also requires some mathematical reasoning. Let's start with the volt. This is the SI (International System) unit of measurement for electric potential. Named for the Italian physicist Volta, who invented the first electric cell and an electrostatic generator, the symbol for volt is V. Batteries, solar cells, and generators are all voltage sources. A 9-volt battery has the potential to make a Walkman or clock work. But until it is connected, nothing happens.

When connected with metal wires to a circuit, volts cause electric currents. Currents are the flow of electrical charges through a metal wire. Electric current is measured in amperes. The SI symbol for amperes is A, but it is commonly abbreviated as "amp." Higher voltage can produce more current. However, there is one more factor that determines how much current will flow through a circuit-- resistance. Resistance comes from the wire and from the "load" connected to the wire. A relationship called Ohm's law states that the amount of current is always directly proportional to the available volts: I=V/R (physics formulas use I for current).

The load is the object using the electrical energy. This object transforms electricity into more visible forms of energy-- light, heat, sound, or movement. These objects are rated in watts, which indicates how much energy it will use. Once a circuit has been set up, the voltage and resistance will be constant. The current is "pulled" or used based on the watts of the "load." A 60-watt bulb will pull more current than a 35-watt bulb. A refrigerator will pull more current than a computer. An ammeter will show the relative amount of current used by each.

Directions Use the Electricity Generator simulation to observe and compare the relative amps used by light bulbs that have different watts.

Procedures 1. Click on the Start Here button and read the text. If you need more information, click and read the Background. Close the window when you are done. 2. From the pull-down menu under Strength of Magnet, select Large. Under Number of Turns of Coil in Wire, select Many. Under Speed to Crank Generator, select Fast. These choices create an electricity generator. 3. The variables that test the current are How To Wire Light Bulb and Wattage Of Light Bulb. Start with 1 bulb and a light bulb that is 35 watts. Click on the Start Generator button.

4. Look closely at the ammeter. There are marks that indicate relative current from 0 to 10. Record your estimate of the reading.

35 watt 60 watt 100 watt 40 watt 75 watt 1 bulb 3 bulbs in a series

5. Repeat this with one 60-watt bulb, and continue with a test of one 100-watt bulb. Record the ammeter reading for each. 6. Now test what happens with three bulbs in a series. Record the ammeter reading for each test. 7. Describe the relationship that you observe between the watts on the circuit and the current being pulled from the generator.

8. Use this relationship to estimate the current for a 40-watt bulb and a 75-watt bulb.

Electricity Simulation: Electricity Activity Two

Introduction An electric circuit is a pathway of wire from a power source to the "load," or object that uses electricity, and back to the power source. The power source can be a battery, a small electromagnetic generator, or a large power station. The current is the flow of electrical charge through the circuit. The amount of current that flows through the circuit depends on the voltage of the power source and the load that is connected to the wire using electricity. A circuit also has a switch. An open switch prevents the flow of electrons. A closed switch closes the circuit and allows electrons to flow through it.

Electricity can flow directly in what is called direct current, or DC. This means that the electricity only flows in one direction. A disadvantage of direct current is that the wire in the circuit acts as a resister and decreases the available current. Over a short distance, this is not noticeable. Alternating current, or AC, moves electrons first one way and then the other through the wires. This allows electrical energy to be transmitted long distances without losing current.

Thomas Edison used direct current in his early efforts to provide electricity to office buildings. Nikola Tesla was able to show that AC current was better. Today, homes are wired with 120-volt alternating current. Batteries are used to provide direct current to flashlights, radios, tape players, cameras, and many other small portable devices.

Directions Use the Electricity simulation to learn more about circuits. After identifying the parts of a circuit, explore the differences between series and parallel circuits.

Procedures 1. Click on the Start Here button and read the text. If you need more information, click and read the Background. Close the window when you are done. 2. From the pull-down menu under Strength of Magnet, select Small. Under Number of Turns of Coil in Wire, select Many. Under Speed to Crank Generator, select Fast. These choices create an electricity generator. 3. The variables that test the current are How To Wire Light Bulb and Wattage Of Light Bulb. You have three choices under each, giving you nine tests on the generator created above. Start with 1 Bulb, and a light bulb that is 35 watts. Click on the Start Generator button. 4. Observe the coils turning, the reading on the ammeter, and the light bulb.

5. What did you do to close the switch? What happened when you closed the switch?

6. Repeat this with one 60-watt bulb, then a 100-watt bulb. Describe your observations. What changed when different light bulbs were tested?

7. Do you think this circuit is using DC current or AC? Why?

Part 2 Most circuits have a load of more than one object. These objects or electrical devices can be wired in a series or in a parallel circuit. When connected in series, there is a single pathway for the electron flow. When the switch is closed, the current flows through all the objects equally. But a break anywhere in the circuit stops the flow. Strings of party lights are often in series. When one bulb burns out, all the other lights stop working because the circuit is now open and there is no current flowing.

A parallel circuit uses branches of wire so that each object is on its own branch. The current flows equally through all the branches, but each has its own separate path for the electron flow. This allows the current to continue flowing even when one device is turned off or stops working.

8. Below are two circuits. Identify which is series and which is parallel. On each, draw line to the power source, load, switch, and wire.

9. Return to the simulation. From the pull down menu under Strength of Magnet, again select Small. Under Number of Turns of Coil in Wire, select Many. Under Speed to Crank Generator, select Fast. Use this generator to test the differences between series and parallel circuits. 10. Complete the table below by combining choices under Wattage of Light Bulb and How to Wire the Light Bulb. Under comments, record anything that is different about the circuit, the wire, or the bulbs.

Circuit Ammeter reading Other observations 35-watt series 35-watt parallel 60-watt series 60-watt parallel 100-watt series 100-watt parallel

11. Summarize the differences you observed between series and parallel circuits.

Electricity Simulation: Elements Activity One

Introduction Elements are rarely found on their own. They are almost always in compounds. Elements are divided into metals and non-metals. Metals have luster and conduct heat and electricity. Non-metals are called electronegative and accept electrons. Hydrogen and carbon are on the list of most commonly found elements--in the Earth's crust, in humans, in the atmosphere and in the universe. Compounds of carbon and hydrogen are called hydrocarbons. One kind of hydrocarbon is isoprene (C5H8). It is a colorless liquid with a pleasant smell that is released by plants.

Amber is fossilized plant resin—an isoprene. Even though it is organic it is considered a gemstone and widely used in jewelry. Amber is also valued as an oddity because of the insects preserved in it.

So what do isoprenes and amber have to do with electricity? The Greek word for amber is "elektor." Elektor and elektron were used to describe amber. About 600 BCE, some Greeks noticed that when they would rub amber against fur, the amber would attract dust, feathers, even straw. The Roman Empire, which followed the Greek Era used the word electricus, which means to "produce from amber by friction." Amber produced static electricity.

Amber is a poor conductor of heat and feels warm to the touch. As a compound of two "non- metal" elements, amber is electronegative. It accepts electrons quite easily. Although observed by the Greeks and Romans, the property of some objects to accept electrons and produce static electricity was not understood until the 17th century. William Gilbert was the first to try to explain electricity and magnetism with a paper written in 1600.

Directions Use the Electricity simulation to explore the flow of electricity through the wire, which is a metal. Apply these observations to predict how electricity would interact with amber, or another non-metal object.

Procedures 1. Click on the Start Here button and read the text. If you need more information, click and read the Background. Close the window when you are done. 2. From the pull down menu under Strength of Magnet, select Small. Under Number of Turns of Coil in Wire, select Many. Under Speed to Crank Generator, select Medium. These choices create an electricity generator. 3. The variables that test the current are How to Wire Light Bulb and Wattage of Light Bulb. You have three choices under each, giving you nine tests on the generator created above. Start with 1 Bulb, and a light bulb that is 35 watts. Click on the Generate Electricity button. 4. Describe how the coils turn, the reading on the ammeter, the light bulb, and the flow of electricity.

5. Repeat this with one 100-watt bulb. Describe the differences you observe between the circuits.

6. The wire pictured is made of a metal. What do you think would happen if you were able to construct a circuit out of a very long thin piece of amber?

Electricity Simulation: Elements Activity Two

Introduction Any metal can conduct electricity and can be used to make e lectrical wire. Wire is a resister in an electrical circuit. Resistance in wire depends on how thick and how long the wire is. The thickness of wire is called its gauge. The smaller the gauge, the bigger the wire. The thickest regular wire is gauge 1; gauge 1 wire has a high resistance. Thin wire has the lowest resistance. To lower the resistance, wire today is made with many thin, tiny wires woven together then covered with a thick plastic outer tubing. The outer tubing provides insulation and "keeps the electricity inside" the wire.

Each metal has a different resistance. The lower the resistance of a wire, the better it conducts electricity. Of the metals, copper is second only to silver in its ability to conduct electricity. Because of its availability, low cost, and ease of recycling, copper is the most commonly used metal in electrical wires. Copper is a heavy metal, number 29 in the periodic table. It is an element that can be found in pure form, but is usually in a compound with sulfur. Common copper ores are chalcopyrite, cuprite, malachite, and azurite. Silver is often in the ore and is a

byproduct of mining copper. Copper has been mined since about 5000 BCE, making it one of the oldest minerals used by humans and directly related to advancements in modern civilization. In some countries, copper, not gold, was the main form of currency. Today, copper is used mainly in building and electrical work.

Directions Use the Electricity simulation to explore the relationship between wires and circuits. Test different generators with both series circuits and parallel circuits to observe the effect of increasingly larger loads on the circuits.

Procedures 1. Click on the Start Here button and read the text. If you need more information, click and read the Background. Close the window when you are done. 2. From the pull down menu under Strength of Magnet, select Small. Under Number of Turns of Coil in Wire, select A Few. Under Speed to Crank Generator, select fast. These choices create the generator. 3. The variables that test the circuit are How to Wire Light Bulb and Wattage of Light Bulb. Select 3 bulbs in a series with 35-watt bulbs. Click on the Generate Electricity button. 4. Look closely at the ammeter. There are marks that indicate relative current from 0 to 10. Record your estimate of the reading in the table below. 5. Repeat this with three 60 watt bulbs in a series circuit, and continue with a test of three 100-watt bulbs in a series circuit. Record the ammeter reading for each.

Ammeter Reading in Series Circuit Generator Three 35-watt bulbs Three 60-watt bulbs Three 100-watt bulbs Small/few/fast

Small/many/fast

Large/few/slow

Large/few/fast

Large/more/slow

Large/more/fast

Large/many/slow

Large/many/fast

6. Now, change the generator. From the pull down menu under Strength of Magnet, select small. Under Number of Turns of Coil in Wire, select many. Under Speed to Crank Generator, select fast. This will increase the potential of the generator. Test the series circuits as indicated in the table. Recording the results of the circuit with the three different watt bulbs. 7. Continue testing generators as indicated in the table. What patterns do you see in the ammeter readings?

8. The wire used in this generator is copper. What can you conclude about the number of turns of copper wire in the generator compared to its output?

9. Look back at your data on the previous page. Not all the generators created were able to get maximum light from the bulbs in the series circuit. Which of the generators do you think will be able to get maximum light from the bulbs if the circuit is changed to parallel wiring?

10. Test your predictions with the simulation. Repeat steps 3 through 7, but under How to Wire the Light Bulbs, select parallel circuit. Record the results in the table below.

Ammeter Reading in Parallel Circuit Generator Three 35-watt bulbs Three 60-watt bulbs Three 100-watt bulbs Small/few/fast

Small/many/fast

Large/few/slow

Large/few/fast

Large/more/slow

Large/more/fast

Large/many/slow

Large/many/fast

11. The wire also will transform some of the electrical energy into heat. When a direct current has a long distance through which the current has to flow, there is less electricity available. Wires used for alternating current allow electricity to flow in both directions. This allows the current to travel a long distance without losing power. Wire used for alternating current has two coated strands inside the main plastic tubing. 12. Do you think the current in the simulation is an alternating current or a direct current? Why?

Electricity Simulation: Light Activity One

Introduction Light from a light bulb is called "artificial light." The incandescent bulb that is used today is not much different than the one invented near the end of 1879. The egg-like shape of a light bulb gives it strength to prevent breaking when put into a light fixture.

Take a close look at the diagram of the light bulb. The tiny coils of wire called filaments are what give off the light we see. The length of that wire determines the amount of light the bulb will produce. In a 60-watt bulb, the filament is about 6 _ feet long, but in small coil that takes up less than an inch in the bulb. The longer the wire, the more intense the light. However, brighter light also results in higher temperatures. The filament typically reaches more than 4,000° F. The filament is made from tungsten. This is a metal that melts, or evaporates, slowly at very high temperatures.

A light bulb has several safety features. Because of the high heat, light bulbs are filled with a gas. In a standard light bulb, this gas mixture is argon and nitrogen. Argon does not conduct heat so it protects the bulb from overheating and slows down the evaporation of the filament. Nitrogen prevents "sparks" from jumping off the filament. When there is a spark, a glass fuse breaks, cutting off the flow of electricity.

The combination of gas and length of filament determines how long a bulb lasts. Many light bulbs are packaged with information about light output (lumens), energy used (watts), and life (hours). But at some point, the filament in all bulbs will "burn out." Too much current can make a bulb overheat or arc, resulting in the bulb burning out much more quickly.

Directions Use the Electricity simulation to test the amount of current used by different sizes of light bulbs. Then explore what happens when a bulb receives too much current.

Procedures 1. Click on the Start Here button and read the text. If you need more information, click and read the Background. Close the window when you are done. 2. From the pull down menu under Strength of Magnet, select Small. Under Speed to Crank Generator, select Fast. Under Number of Turns of Coil in Wire, select Few . 3. Under How to Wire the Light Bulb, select 1 Bulb. You will keep this constant while testing different watts. Under Wattage of Light Bulb you have three choices. Start with 35 watts. 4. Click on the Start Generator button. Estimate and record the reading from the ammeter in the table below.

Ammeter Reading Generator 35 watt 60 watt 100 watt Small/few/fast Small/more/fast Small/many/fast Large/few/fast Large/more/fast Large/many/fast

5. Repeat this for the remaining bulbs and generators in the table.

6. What did you learn about watts, currents, and light bulbs?

Electricity Simulation: Light Activity Two

Introduction Ever notice how hot a light bulb gets? Only about 10% of the electricity that flows through the bulb is transformed into visible light. The rest is transformed into heat and infrared or ultraviolet light waves that the human eye cannot see.

Visible light waves make up a very small part of the electromagnetic spectrum. Each color has a different wavelength. Red has the longest wavelength and violet has the shortest. When all the waves are together, they make white light.

Light produced by light bulbs is measured in lumens. A standard light bulb produces between 10 and 18 lumens per watt. Higher-wattage bulbs give more light per watt than lower-watt bulbs. Halogen lights produce 14-20 lumen per watt, and fluorescent produce 60 to 90 lumens per watt.

Directions Use the Electricity simulation to learn more about lumens produced by light bulbs. Explore how changing the type of light bulb to get more lumens per bulb can result in using less electrical energy.

Procedures 1. Click on the Start Here button and read the text. If you need more information, click and read the Background. Close the window when you are done. 2. From the pull down menu under Strength of Magnet, select Small. Under Number of Turns of Coil in Wire, select Many. Under Speed to Crank Generator, select Fast. These choices create an electricity generator. 3. The variables that test the current are How to Wire the Light Bulb and Wattage of Light Bulb. Start with 1 Bulb and a light bulb that is 35 watts. 4. Look at the table below. The bulbs in this simulation are regular incandescent bulbs. Use the information above to estimate the potential lumens that each circuit could produce. Record your estimates for each under "potential lumens."

Light Produced by Small Generator Bulb size

35 watt 60 watt 100 watt Circuit Potential Produced Potential Produced Potential Produced

Lumens yes/no Lumens yes/no Lumens yes/no 1 bulb 3 bulbs in series 3 bulbs in parallel

5. Click on the Start Generator button. Based on the "glow" of the 35-watt bulb, indicate whether the maximum potential lumens were produced. Record this as yes or no under "produced." 6. Keep the generator the same while testing the other light bulbs. Indicate whether the maximum potential was produced in each trial. 7. Then test 3 Bulbs in Series with the same generator. Indicate whether the maximum potential was produced. 8. Repeat the steps above for the indicated 3 Bulbs in Parallel Circuit. 9. Compare the potential lumens from one 100-watt bulb and three 35-watt bulbs. Also compare three 60-watt bulbs to two 100-watt bulbs. What do you notice? Was there any difference in the maximum produced when the potential lumens were similar ?

10. Now change the generator. From the pull down menu under Strength of Magnet, select Large. Under Number of Turns of Coil in Wire, select Many. Under Speed to Crank Generator, select Fast. These choices create a second electricity generator. Will the potential lumens be the same? Why?

Light Produced by Large Generator Bulb size

35 watt 60 watt 100 watt Circuit Potential Produced Potential Produced Potential Produced

Lumens yes/no Lumens yes/no Lumens yes/no 1 bulb 3 bulbs in series 3 bulbs in parallel

11. Test the available current and lumens produced by this larger generator. Based on the "glow" of the bulbs, indicate whether the maximum potential lumens were produced. Record this as yes or no under "produced." 12. The desired lumens for general lighting in a living room or dining room is usually around 1500. A kitchen or work area needs more. Use the information from the introduction to estimate the watts needed to produce a desired amount of light with a standard incandescent, a halogen, and a compact fluorescent bulb.

Living room Kitchen Type of bulb 1500 lumens 3200 lumens

1 bulb 3 bulbs in a 3 bulbs in 1 bulb 3 bulbs in a 3 bulbs in series parallel series parallel

Standard Incandescent Halogen Compact Fluorescent

13. What can you conclude about the type of bulb and lumens produced?

14. What do you think is the most efficient way to get the needed light?