Monday, October 19, 2015

October 19-23

Period 1 Ag 2
Monday: Weekly Ag Article Review 
Tuesday: Electricity: How it Works

Unit:                           Electricity
Lesson Title:              Electricity - How It Works   
Estimated Time:        50 minutes
Need:                          Students not having any former instruction in electricity will develop a basic understanding of how electricity is generated and the various units of electricity such as amperes, ohms, volts, and watts.
Objectives:
1.     Without references students will interpret how electricity is generated as described in class.
2.     Students will be able to define and distinguish the difference between the concepts of amps, ohms, volts, and watts.
Applied Academic Competencies:  Math Science
Essential Equipment, Resources & Supplies:
1.               Strips of various metals such as copper, aluminum, brass, and steel.
2.               Fruit and vegetables brought in by students.
3.               Test equipment which can measure small amounts of current
4.               Electricity Lesson 1 PowerPoint
Teaching Procedures:
Interest Approach:
Have student bring in various fruits and vegetables which will be used to chemically create an electrical current by inserting the metal strips into the fruit or vegetable and measuring current across the two pieces of metal.  Fruits which are highly acidic such as lemons will tend to produce more current with a copper strip.
Presentation:
1.       What is matter?
a.      Anything which occupies space and has weight is called matter. All liquids, gases, and solids are matter. Matter is made up of smaller units called atoms
2.       Atoms, what are they?
a.      Atoms resemble the solar system with the sun as the center around which a series of planets revolve. The center is called the nucleus and the electrons revolve in an orbital pattern.
3.       What is an electrical charge?
a.      Material is said to have an electrical charge when it attracts or repels another charged material. It may either be a positive (+) or negative (-) charge.
4.       What are protons and neutrons?
a.      Part of the nucleus of an atom is made up of protons. Protons are positive charges and attract electrons. Neutrons are electrically neutral.  They can neither attract or repel other electrical charges.
5.       What is an electron?
a.      Electrons revolve continuously about the nucleus of an atom (just like the planets and sun). Electrons possess a negative charge and are lighter than protons. An atom contains the same number of electrons as there are protons.
  1. Electricity can be used to create what three things?
a.      Light
b.     Heat
c.      Magnetism
  1. What is current?(amperes)
    1. Electrons in motion result in an electrical current. Copper wire is often used to carry electrical current. When electrical pressure (voltage) from a battery or generator is applied, it is possible to force the electrons from atom to atom along the length of the wire (conductor) creating amperes.
  2. What are the different types of current?
    1. Direct current (dc) is the movement of electrons in one direction in a conductor.
    2. Pulsating direct current is a current in one direction which varies in intensity at a regular interval of time.
    3. Alternating current (ac) is a current which changes in direction and intensity at a regular interval of time.
  3. What is voltage?
    1. Electrical pressure is known as voltage. The source can be obtained from batteries, generators, and other sources. The generator is the most common source because of the commercial applications.
    2. The letter E is used to represent voltage.
    3. Volt (V) is the unit used to express the quantity of electrical pressure.
    4. The instrument used to measure V is a voltmeter.
  4. What are watts?
    1. Measure of the amount of energy or work that can be done. Often expressed in kilowatt hours.
11.  How does this relate to water in a pipe?
a.      Amperes or amps is current so the amount of water moving in the pipe (gallons per minute).
b.     Volts is the amount of pressure in the pipe (pounds per square inch).
c.      Watts is the total volume of water moved over a period of time.
  1. What is watts law?
    1. Watts law is used to show the relationship of current, voltage, and watts.
    2. Watts = Amps x Volts
  2. What is electrical polarity?
    1. All dc sources of electricity have two terminals to which electrical devices are connected. These have polarity, one is positive (+), and the other is negative (-).
  3. What is resistance?
    1. The property of a material which causes it to oppose the movement of electrons is called resistance (R). All materials have some resistance.
    2. Materials that offer little resistance to electron movement are called conductors.
    3. Materials that offer high resistance are called nonconductors or insulators.
    4. R is measured by an ohmmeter and the Greek symbol Omega (Ω) represents ohms. All electrical power must be disconnected in a circuit when using an ohmmeter.
  4. What is Ohms Law?
    1. Ohm’s Law is used to show the relationship of current, voltage, and resistance.
Ohm’s law: In any electrical circuit the current is directly proportional to the voltage applied to the circuit and is inversely proportional to the resistance in the circuit. Note: Both resistance and voltage affect the current.
    1. Example: current will increase when the voltage is increased, and current will decrease when the voltage is decreased.  Similarly, when the voltage is constant, current will increase when the resistance is decreased, and current will decrease when resistance is increased.
  1. Demonstrate processes described above.
    1. Equation for Ohm’s Law: I=E/R
    2. Where I = intensity of current in amperes, E = quantity of electrical pressure in volts, R = amount of resistance in ohms
    3. Other forms of expressing Ohm’s Law: E=IR and R=E/I
Application:
a.     Students will practice Ohm’s Law concepts and determine types of current.
b.     Take a field trip to a nearby powerplant.
Evaluation:
a. Students will be given a test over concepts, principles and math skills


Wednesday: Applying Ohm's Law

Unit:                           Electricity
Lesson Title:              Applying Ohm’s Law
Estimated Time:        50 minutes
Need:                          Electricity is important in agriculture because of the power it provides.  In this unit you will learn about the terms, measurements and relationships that describe electrical power.
Objectives:
1.     Each student will be able to understand the formula for calculating volts, amperes, resistance.
  1. Given a problem by the instructor, each student will be able to decide the proper formula to apply to arrive at the correct answer.
Applied Academic Competencies:  
Math
Science
Essential Equipment, Resources & Supplies:
1.     Electric motor name plates with specifications.
2.     Electricity Lesson 2 Handout
Teaching Procedures:
Interest Approach:
  1. Examine the name plate on an electrical motor and have the students determine the volts, amps and ohms and explain to them that we will be calculating volts, amps and ohms using Ohm’s Law
Presentation:
  1. Give students a problem on the board with one unknown factor.
    1. Explain to the students that resistance is measured in ohms and the Greek symbol Omega (Ω)is used to express resistance in the metric system.
  2. VALUES TO KNOW:
    1. W = Power, in watts
    2. E = voltage
    3. I = current, in amperes
    4. R = resistance (measured in ohms)
  3. What does it mean when a light bulb has on the top 60 watts or 100 watts?
    1. Wattage is a basic unit of electrical power therefore
    2. (Watts) W = I (Amps) x E (Volts).

  1. If you have a 60 watt light bulb in a 120V circuit, how many ohms and amps are in the circuit?
    1. Explain to students how to figure the amps and ohms by using the formula.
    2. 60 = I x 120
    3. I = 60/120 = .50
    4. R = E/A therefore
    5. R = 120/.50 = 240 ohms or resistance.
    6. Give students several problems and have them work through them using the formula.
  2. Ohm’s Law allows you to determine an unknown third value if the remaining two values are known.
    1. E = I x R
    2. assume that 6 A of current flows in a circuit having a total resistance of 20 ohms.  What is the circuit=s source voltage?  Insert the known values for current and resistance into the formula, it is determined that the circuit has a 120 volt source.
    3. E = I x R
    4. E = 6 A x 20 ohms
    5. E = 120 volts
  3. Ohm’s Law equation can be rearranged to solve for any of the three values as long as the other two values are known.
    1. EXAMPLES:
                                                    i.     I = E/R
                                                  ii.     I = 120 V/45 ohms
                                                iii.     I = 2.7 A
    1. EXAMPLE 2
                                                    i.     R = E/I
                                                  ii.     R = 12 V / 1.2 A
                                                iii.     R = 10 ohms
Application:
Follow up the next day at the beginning of class and have students work through a problem to help them learn the concept.
Evaluation:
Prepare a short quiz or worksheet.
Suggested Supplemental Resources:
1.               Basic Electricity & Practical Wiring, Hobar Publications, 1980
2.               FOS - Electronic and Electrical Systems, Deere & Company, 1993.

3.               Mechanical Technology in Agriculture, Interstate Publishers, 1998.
Thursday-Friday: Bank of the Rockies Scarecrow Contest: Theme, materials needed, and plans 

Period 2 Ag 4
Monday: Weekly Ag Article Review 
Tuesday: Wildlife Escape Ladder Fabrication 
Wednesday: Wildlife Escape Ladder Fabrication 
Thursday: Plans for chicken coop 
Friday: List of materials and plans for chicken coop (draw a draft of chicken coop that will be built in class)

Period 3 7th Grade Ag
Monday:  FFA Scavenger Hunt DUE TODAY 
Tuesday: Our Nations Commodities
Wednesday: Our Nations Commodities
Lesson Plan: https://www.ffa.org/myresourcedocuments/MS.IAS.4.2.pdf
Thursday: Defining Agriculture: Imports and Exports 
Friday: Defining Agriculture: Imports and Exports
Lesson Plans: https://www.ffa.org/myresourcedocuments/MS.IAS.4.1.pdf

Period 5 Ag 3
Monday: Weekly Ag Article Review 
Tuesday-Friday: Oxy-Acetylene Welding (flat beads) 

Period 6 8th Grade Ag 
Monday-Friday: Montana County Agriculture Map (DUE 10/30) 

Period 7 Ag 1
Monday: Weekly Ag Article Review 
Tuesday-Friday: Oxy-Acetylene Welding (flat beads) 

Posted by at

No comments:

Post a Comment

Subscribe to: Post Comments (Atom)