Download
1 / 36
360 likes | 449 Views
Science Lesson Plan 1 Electricity Audit. By Darwin Daugaard. Context Issues of the Lesson. Planning Stages Within the 5-E Inquiry Model. HS-ETS-ED Engineering Design
E N D
Science Lesson Plan 1 Electricity Audit By Darwin Daugaard
HS-ETS-ED Engineering Design a. We can have the students ask and collect data on energy consumption to find evidence of machines that utilize large amounts of energy. b. Higher level classes could propose methods of reducing energy consumption based on energy audit. c. No d. No e. No f. No HS – ETS-ETSS Links Among Engineering, Technology, Science, and Society A. Students utilize the energy audit to plan how they may reduce energy consumption. B. No C. Students could look at a specific device to determine what device is most energy efficient. They could compare this to energy star rates to make comparison and come up with suggestions. D. High level groups could look into comparing the price to change from one device to another. For instance, purchase of new appliance when old appliance is still functional.
Current and Voltage Difference • The net movement of electric charges in a single direction is an electric current. • When an electric current flows in the wire, electrons move randomly movement, but they also drift in the direction that the current flows. • Electric current is measured in amperes.
Voltage Difference • In some ways, the electric force that causes charges to flow is similar to the force acting on the water in a pipe. • Water flows from higher pressure to lower pressure.
Voltage Difference • In a similar way, electric charge flows from higher voltage to lower voltage. • A voltage difference is related to the force that causes electric charges to flow. Voltage difference is measured in volts.
Electric Circuits • A closed path that electric current follows is a circuit. • If the circuit is broken current will not flow.
Batteries • To keep an electric current continually flowing in the electric circuit a voltage difference needs to be maintained in the circuit. • A battery can provide the voltage difference that is needed to keep current flowing in a circuit. • Current flows as long as there is a closed path that connects one battery terminal to the other battery terminal.
Dry-Cell Batteries • A cell consists of two electrodes surrounded by a material called an electrolyte. • The electrolyte enables charges to move from one electrode to the other.
Dry-Cell Batteries • One electrode is the carbon rod, and the other is the zinc container. • The electrolyte is a moist paste containing several chemicals. • The cell is called a dry cell because the electrolyte is a moist paste, and not a liquid solution.
Wet-Cell Batteries • A wet cell contains two connected plates made of different metals or metallic compounds in a conducting solution. • A wet-cell battery contains several wet cells connected together.
Lead-Acid Batteries • Most car batteries are lead-acid batteries. • A lead-acid battery contains a series of six wet cells made up of lead and lead dioxide plates in a sulfuric acid solution. • The chemical reaction in each cell provides a voltage difference of about 2 V, giving a total voltage difference of 12 V.
Resistance • As the electrons flow through the filament in a lightbulb, they bump into the metal atoms that make up the filament. • In these collisions, some of the electrical energy of the electrons is converted into thermal energy. • Eventually, the metal filament becomes hot enough to glow, producing radiant energy that can light up a dark room.
Resisting the Flow of Current • Resistance is the tendency for a material to oppose the flow of electrons, changing electrical energy into thermal energy and light. • Resistance is measured in ohms ().
Temperature, Length, and Thickness • The electric resistance of most materials usually increases as the temperature of the material increases. • The resistance of a wire, or any conductor, increases as the wire becomes longer. • The resistance also increases as the wire becomes thinner.
The Current in a Simple Circuit • A simple electric circuit contains a source of voltage difference, such as a battery, a device, such as a lightbulb, that has resistance, and conductors that connect the device to the battery terminals. • When the wires are connected to the battery terminals, current flows in the closed path. • The voltage difference, current, and resistance in a circuit are related.
Ohm's Law • According to Ohm's law, the current in a circuit equals the voltage difference divided by the resistance. • Ohm's law provides a way to measure the resistance of objects and materials. First the equation above is written as:
Question1 __________ is the net movement of electric charges in a single direction. A. An open circuit B. Electric current C. Proton flow D. Voltage
The answer is B. Electric forces in a material cause electric current to flow.
Question 2 What is a volt? Answer A volt is the unit of measurement for voltage difference, which is related to the force that causes electric charges to flow.
Question 3 What is the tendency for a material to oppose the flow of electrons called? Answer The tendency for a material to oppose the flow of electrons is called resistance, and is measured in ohms.
Activity 1 The students will be handed a flashlight and asked to put the batteries in them in both directions. They will be given time to discuss their results in their groups and then asked to share with the class. Back to lesson plan.
The students will do an activity putting together a simple circuit, a series circuit and a parallel circuit. Back to lesson.
ME Energy Audit Assessment • Determine the amount of total money from using ten (10) of the following appliances for the time allotted for each for a thirty day month. All units will be in Watts (W). Calculate the kilowatt hours at a cost of $0.102 per kilowatt hour • Clock radio = 10 for 24 hours • Coffee maker = 900–1200 for 1 hour • Clothes washer = 350–500 for 2 hours • Clothes dryer = 1800–5000 for 2 hours • Dishwasher = 1800 for 2 hours (using the drying feature greatly increases energy consumption) • Dehumidifier = 785 for 24 hours • Fans • Ceiling = 120 for 10 hours • Window = 150 for 10 hours • Furnace = 750 for • Hair dryer = 1550 for ½ hour • Clothes iron = 1400 for ½ hour • Microwave oven = 925 for 1 hour • Personal computer • Laptop = 50 for 12 hours • Radio (stereo) = 230 for 3 hours • Refrigerator (frost-free, 16 cubic feet) = 725 for 24 hours • Televisions (color) pick one for 6 hours • 19" = 65–110 • 27" = 113 • 36" = 133 • 53"-61" Projection = 170 • Flat screen = 120 • Toaster = 1100 for ½ hour • VCR/DVD = 20 for 1 hour • Vacuum cleaner = 1220 for 1 hour • Water heater (40 gallon) = 5000 for 24 hours Back to lesson.
Physical Science Test C-Electricity • 1. A radio uses 3.5 X 10-3 A of current when it is operated by a 4.5 volt battery. What is the resistance of the radio circuit? • 2. A 23 ohm electric heater operates on a 120 volt outlet. • What is the current through the heater? • How much energy is used by the heater in 40 seconds? • How much thermal energy is given off in this amount of time? • 3. Three 30 ohm resisters are connected in series across a 120 volt generator. What is the equivalent resistance in the circuit? • What is the current in the circuit? • 4. Three 30 ohm resisters are connected in parallel across a 120 volt generator. What is the equivalent resistance in the circuit? • What is the current in the circuit? • 5. TJ’s lovely PS-2 has a resistance of 134 ohms and is plugged into a 120 volt outlet. • How much current does it draw? • How much power does it use? • If TJ’s dad pays 27 cents per KWh how much does it cost to run the PS-2 for 4 hours a day for a 30 day period? Lesson Plan
Resources 1. Lesson Plan template- found one on the web and changed it. 2. Power point from Glencoe Physical Science 1995. 3. The Easy Energy Action Plan – LoseYourExcuse.com 4. Energy Audit of Household Appliances-Engineering the future Workshop. 5. Home Energy Audit- Coolschoolchallenge.org 6. Lesson Plan template- found one on the web and changed it. 1. Lesson Plan template- found one on the web and changed it.
