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
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.
- Electricity can be used to create
what three things?
a.
Light
b.
Heat
c.
Magnetism
- What is current?(amperes)
- 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.
- What are the different types of
current?
- Direct current (dc) is the
movement of electrons in one direction in a conductor.
- Pulsating direct current is a
current in one direction which varies in intensity at a regular interval
of time.
- Alternating current (ac) is a
current which changes in direction and intensity at a regular interval of
time.
- What is voltage?
- 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.
- The letter E is used to represent
voltage.
- Volt (V) is the unit used to express
the quantity of electrical pressure.
- The instrument used to measure V
is a voltmeter.
- What are watts?
- 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.
- What is watts law?
- Watts law is used to show the
relationship of current, voltage, and watts.
- Watts = Amps x Volts
- What is electrical polarity?
- 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 (-).
- What is resistance?
- The property of a material which
causes it to oppose the movement of electrons is called resistance (R).
All materials have some resistance.
- Materials that offer little
resistance to electron movement are called conductors.
- Materials that offer high
resistance are called nonconductors or insulators.
- 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.
- What is Ohms Law?
- 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.
- 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.
- Demonstrate processes described
above.
- Equation for Ohm’s Law: I=E/R
- Where I = intensity of current in
amperes, E = quantity of electrical pressure in volts, R = amount of
resistance in ohms
- 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.
- 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.
Teaching Procedures:
Interest Approach:
- 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:
- Give students a problem on the
board with one unknown factor.
- 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.
- VALUES TO KNOW:
- W = Power, in watts
- E = voltage
- I = current, in amperes
- R = resistance (measured in ohms)
- What does it mean when a light bulb
has on the top 60 watts or 100 watts?
- Wattage is a basic unit of
electrical power therefore
- (Watts) W = I (Amps) x E (Volts).
- If you have a 60 watt light bulb in
a 120V circuit, how many ohms and amps are in the circuit?
- Explain to students how to figure
the amps and ohms by using the formula.
- 60 = I x 120
- I = 60/120 = .50
- R = E/A therefore
- R = 120/.50 = 240 ohms or
resistance.
- Give students several problems and
have them work through them using the formula.
- Ohm’s Law allows you to determine
an unknown third value if the remaining two values are known.
- E = I x R
- 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.
- E = I x R
- E = 6 A x 20 ohms
- E = 120 volts
- Ohm’s Law equation can be
rearranged to solve for any of the three values as long as the other two
values are known.
- EXAMPLES:
i. I = E/R
ii. I = 120 V/45
ohms
iii. I = 2.7 A
- 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)
