## ElectrostaticsEdit

### 1. NJ standards addressed in the unit Edit

**5.1.12**

A1 - When making decisions, evaluate conclusions, weigh evidence, and recognize that arguments may not have equal merit.

A2 - Assess the risks and benefits associated with alternative solutions

A3 - Engage in collaboration, peer review, and accurate reporting of findings.

A4 - Explore cases that demonstrate the interdisciplinary nature of the scientific enterprise.

B1 - Select and use appropriate instrumentation to design and conduct investigations.

B2 - Show that experimental results can lead to new questions and further investigations

C1 - Understand, evaluate and practice safe procedures for conducting science investigations

**5.2.12**

B1 - Examine the lives and contributions of important scientists who effected major breakthroughs in our understanding of the natural and designed world.

B3 - Describe the historical origin of important scientific developments… showing how scientific theories develop, are tested, and can be replaced or modified in light of new information and improved investigative techniques.

**5.3.12**

A1 - Reinforce indicators from previous grade levels (estimation, measurements, and computations of quantities, orders of magnitude, expressing quantities in decimals, scientific notation, fractions, percents and integers)

B1 - When performing mathematical operations with measured quantities, express answers to reflect the degree of precision and accuracy of the input data.

C1 - Apply mathematical models that describe physical phenomena to predict real world events.

D1 - Construct and interpret graphs to represent inverse and non-linear relationships and statistical distributions.

**5.4.12**

A1 - Know that scientific inquiry is driven by the desire to understand the natural world and seeks to answer questions that may or may not directly influence humans, while technology is driven by the need to meet human needs and solve human problems.

**5.7.12**

A4 - Recognize that electrically charged bodies can attract or repel each other with a force that depends upon the size and nature of the charges and the distance between them and know that electric forces play an important role in explaining the structure and properties of matter.

B1 - Explain how the various forms of energy (heat, electricity, sound, light) move through materials and identify the factors that affect that movement.

### 2. Length total (days and periods) Edit

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### 3. Prerequisite Edit

1. An understanding of kinematics and Newtonian dynamics.

2. An understanding of Newton’s Universal Law of Gravitation.

3. An understanding of a system, the object’s involved and the associated processes.

4. The ability to create and interpret energy bar charts for a well defined system.

### 4. Goals Edit

#### ConceptualEdit

1. Understand the charge model and how to apply it at a microscopic level to conductors and insulators.

a. Understand that there are two types of electric charges (positive and negative). b. Understand that charged particles can move freely in certain material, but in other materials they can only redistribute slightly. c. Neutral objects have equal positive and negative electric charge. d. Understand the role of humidity on electrostatic interactions. e. Charged can be transferred by contact (rubbing causes some objects to become charged)

2. To apply, dynamics and conservation of energy to systems of charged particles/objects.

3. To distinguish between the types of electrical interactions. Distinguish electrical interactions from interactions between magnetic poles. Distinguish electrical interactions from gravitational interactions.

4. To recognize that charge is conserved.

#### QuantitativeEdit

1. Develop and understand the relationship of forces between charges (Coulomb force)

2. Develop and understand the relationship of potential energy of the systems of charges.

3. Understand the field model, quantitatively for fields and V fields.

4. Differentiate between an inverse relationship and an inverse squared relationship.

5. Understand the role of an object that is either a test charge or a source charge, in the quantitative development of the fields and V fields.

6. Utilize the principle of superposition to calculate the fields and V fields a point charge, multiple point charges and continuous distributions of charge.

#### Procedural Edit

1. To develop multiple representations for electrical systems, fields and V fields

2. To utilize force diagrams and energy bar charts for interactions of charged objects/particles

3. To introduce and utilize potential graphs and equipotential surfaces

#### EpistemologicalEdit

1. Formulate explanations for phenomena based on observational evidence and develop strategies to experimentally test these explanations.

2. To develop, analyze, implement and utilize mechanisms and analogies for the interactions of any system that we can not physically see.

3. Learn to make convincing arguments based on scientific reasoning to explain processes involving electric charges.

4. Learn how this new unit relates to Newtonian concepts and other previous knowledge.

### 5. Key Concepts and Cross-Curricula Links Edit

### 6. Potential Difficulties Edit

1. Many students believe that insulators cannot be charged.

2. Do not distinguish between an insulator and conductor and its charged state.

3. Do not distinguish between charge and current

4. Students think of charge as an object rather than a property of matter. Charge can be “painted on” to matter. This idea is reinforced by “two charges” not “two charged objects…”

5. Students do not recognize conservation of charge

6. Students think there is a fundamental reason that electrons have to be negative.

7. Many students think a positively charged particle has an excess of protons

8. Students have little or no understanding of the structure or atomic properties of solids.

9. Establishing the idea that the point of no interaction is the ideal spot for zero potential energy.

10. All systems will tend to move towards less (zero) potential energy.

11. An attractive force has an associated negative potential energy

12. Associating the mass of a charged particle with its charge. Students have difficulty with deciphering between the two.

13. Students will associate the force exerted on an object to be the direction of motion, of that object, which is not necessarily the case. The students need to take into the account the initial motion of the charged object.

### 7. Relevance Edit

### 8. Curriculum Materials Edit

### 9. Full Two Period Lab Edit

### 10. Traditional and Alternative Summative Assessments Edit

#### Traditional AssessmentEdit

File:Quiz-Charges and Energy.doc

File:Quiz-Electric Charges.doc