simple circuit powering a LED

Basic Electricity K6-8 Learning objectives

Learning objectives for Basic Electricity K6-8

ELECTRICITY BASIC CONCEPTS Bloom Taxonomy
Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 9-10 texts and topics. (CCSS.ELA-LITERACY.RST.9-10.4) Low level

Current

1.      Relate electrical energy to forces of repulsion or attraction between electric charges.

2.      Recognize an electromagnetic field is created by static (electric field) and moving (magnetic field) charges.

3.      Recognize how current is created by batteries:

a.      Specify how batteries create current by conversion of chemical energy.

b.      Define the concept of battery EMF.

c.       Describe current flowing in a circuit, from the negative end to the positive end of a battery.

4.      Recognize how current is created by generators:

a.      Sketch electric current created by a magnetic field at right angles to the direction of the current.

b.      Specify how generators convert mechanical energy into electrical energy.

5.      Distinguish between direct current flowing continuously in one direction and alternating current reversing its direction at regular time intervals. Frequency = 50 Hz (Europe), 60 Hz (USA)

6.      Describe how current is related to charge and time. I=ΔQ/Δt

 

Application

Comprehend

 

Comprehend

Knowledge

Knowledge

Knowledge

Comprehend

Knowledge

Knowledge

Knowledge

 

Knowledge

Voltage

1.      Explain that electric potential energy arises due to the place where the object is placed within an electromagnetic field.

2.      Describe the electric potential, or voltage, as the difference in potential energy between two locations.

3.      Classify EMF as a special type of potential difference.

4.      Recognize electric potential exists even if there is no charged particle.

5.      Recognize electric current in a circuit due to electrons being pushed from a negative to a positive potential.

6.      Define the unit of potential difference are joules per coulomb, known as volt.

 

Comprehend

Knowledge

Analysis

Analysis

Comprehend

Knowledge

Ohm’s Law and Resistance

1.      State Ohm’s law. (IV, I =V/R, V=IR)

2.      Describe Ohm’s law (the current through a conductor is proportional to the voltage drop across a current-carrying conductor.)

3.      Define resistance and the Ohm unit.

4.      Recognize Ohmic material as a material that obeys Ohm’s law such as copper, gold, graphite, saline water, etc.

5.      Explain how resistance decreases the flow of charge through it

6.      Calculate what happens to the current of a circuit when either the voltage orresistance is increased or decreased.

7.      (higher level) Recognize that when current passes through a resistor, charges lose potential energy.

8.      Determine resistance from Current-Voltage Graph

9.      Examine electrical conductivity, insulator, and conductor material that allows an electric current to pass through it.

10.   Select and use correct operations and appropriate methods to solve Ohm’s law problems.

Knowledge

Comprehend

Knowledge

Knowledge
Comprehend

Application

Synthesis

Analysis

Analysis

Analysis/Evaluate

Basic Circuit

1.      Sketch a simple circuit powering a light a bulb (LED) with a battery, resistance, and wire.

2.      Identify the essential components of a simple circuit (switch, battery, resistor, LED, light bulbs, wires, AC voltage sources, fuse).

3.      Draw a circuit diagram for a given circuit and show an arrow indicating the direction of the current.

4.      Explain how a simple switch can be used to control the flow of electrical energy (close, open, and short a circuit)

5.      Examine circuit diagrams to determine how current flows.

6.      Analyze how current, voltage, and resistors are interrelated and how they vary when conditions change.

7.      Review series circuit and resistors connected in series:

a.      determine an unknown resistance.

b.      calculate an equivalent resistance. Requiv=R1+R2+⋯+RN

8.      Parallel circuits and resistors connected in parallel:

a.      Determine an unknown resistance.

b.      Calculate an equivalent resistance. Requiv=11/R1+1/R2+⋯+1/RN

9.      Solve problems using reasoning with equivalent resistances.

10.   Select and use correct operations and appropriate methods to solve circuit problems.

Bloom Taxonomy

Knowledge

Knowledge

Application

Comprehend

Analysis

Analysis

Comprehend

Comprehend

Analysis

Comprehend

Comprehend

Analysis

Analysis/Evaluate

Analysis/Evaluate

 

Electric Power

1.       Define electric power as the rate at which electric energy is transferred in a circuit.

2.      Clarify how voltage, resistance, current, and power are all related as shown on a formula wheel and formula.

3.      Explain how Electric power is proportional to the current through the resistor multiplied by the voltage across the resistor.

 

4.      Review Formula:

a.      For a given current I flowing through a potential difference V, the electric power dissipated is P=IV

b.      for a given current I flowing through a resistance R, the electric power dissipated is P=I2R

c.       for a given voltage difference V across a resistor R, the electric power dissipated is P=V2R

5.      Solve the power dissipated through a branch of a circuit.

6.      Select and use correct operations and appropriate methods to solve power problems.

Bloom Taxonomy

Knowledge

Comprehend

Application

Knowledge/ Comprehend

Application

Application

Application

Application

Analysis/Evaluate

NOTES on DIFFICULT TOPICS

  • Explain the Concept of EMF. Emf creates a potential difference, causing current flow.
  • Describe a microscopic model for current in a simple circuit with a battery, wire, and a resistance. Visualize a wire as a pipe filled with millions of electrons bouncing around and interacting with repulsion/attraction electric forces. When a difference in voltage is applied and pushes negative charges, then, the pack of electrons is drifting slowly, but the current is established almost instantly due to electric field propagation through the wire at the speed of light.
  • For a circuit there is a current which creates a magnetic field which wraps circularly around the wire. There are also surface charges which produce an electric field which is directed radially outward outside of the wire. The direction which is perpendicular to both the radial electric field and the circumferential magnetic field is directed along the wire. This means that electromagnetic energy flows along the wire in the space outside the wire.
  • Resistance causes heat and voltage’s drop, but velocity of electrons and current flow do not change, beware: the analogy with water flow is quite misguiding. Better to use the friction analogy, more obstacles dissipating energy and resulting in heat increase with less overall potential energy outside the resistance, thus a drop in voltage.

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