Grade Level: 12 grade physics Date: 12/15/2014
Unit/Subject: Chapter 5, Section 5 || Electrostatics Lesson IV: Electric energy and potential
Big Idea:
We’ve learned that there are two kind of charges: positive and negative. Now the question is this: how can you separate these two charges? Answer is simpler: we need to do some work against the force of attraction or repulsion.
Hypothesis:
H0: µ0: Electricity is a form of energy
Ha: µa: Electricity is not a form of energy
Standard:
Beyond the use of reasoning and consensus, scientific inquiry involves the testing of proposedexplanations involving the use of conventional techniques and procedures and usuallyrequiring considerable ingenuity
Objective:
Students should be able to link between gravitational and electrical potential energy to understand the concept.
Instructional Strategy (IMPROVISENeed, novelty, meaning & emotion)
I. There are four ways our brain hooked into a speech—need, novelty, meaning and emotion. If a mini-lesson has even one of these hook—it will stand a good chance of being remembered. My mini-lesson, “Electrical energy & potential” which I will present on above date—have not only one—but all four hooks.
II. I learned that part of teaching is to improvise. Improvisation may sound contradicting to what I have previously wrote in lesson plan #I, but let me explain what I mean. A teacher can only prepare so much for a lesson. He or she may have answers to questions that they potentially think the students may ask because of the lesson being taught. However, not every question or scenario may be covered prior to the lesson; being that students are so spontaneous and curious, especially when you have their attention. However, the improvisation most strictly be aligned with the lesson's objective. For example, other day a student mentioned that he know I came from India. I had no idea he was going to mention that. However, because of that student, I was able to add a new idea to my lesson. In a similar way, a teacher needs to be responsive to it students input and from time to time try to incorporate their ideas in the lesson. I believe it would make a lesson that much effective because students would noticed that you have listened to what they said and did not simply ignore it.
Assessments:
Type of assessment / Weight / Percent
Do now / Will be graded / 10%
Class participation/good behavior / Will be graded / 5%
Group lab demonstration / Will be graded / 5%
Exit Slip / Will be graded / 10%
Home-work / Will be graded / 20%
Exam / Will be graded / 50%
Total / 100%
How to differentiate (Wait time)
Wait Time allows student (in this case, I am taking more time to write a response on the board) more time to respond. The short time goal of this is to allow more time to below the average students to chew on the question before they answer. And the long term goal is to encourage students to be like tortoise rather than to be like hare.
Grouping (Experimental):
I will arrange classrooms by ability: placing the highest-achieving students in one cluster, the lowest in another.
Materials
- Vinegar
- Glasses (15)
- copper and zinc strips
- Connencting wires
- LED bolt
Lesson agenda
Agenda / Time
Do now / 5 minutes
Mini lesson / 15 minutes
Student activities (building battery) / 10 minutes
One group will presenting it for class / 10 minutes
Exit slip / 5 minutes
Agenda / TIME
Do now / 5 min
I. Draw Vinegar Battery model on a sheet of paper
II. How would you describe the charges?
Students are to write their answers to the “Do Now” on slips of paper handed to them as they enter the classroom. Three students will be selected randomly to put their answers on the board while the remainder of the class finishes. The slips of paper will be collected, and the answers will be reviewed.
Handouts # 1
Vocabulary on the front page
- Electric energy
- Electric potential
- Potential diference (Volt)
- Battery
- Ohm’s Law
- Resistance
Focus question on the back page
- Why mass in GF has GPE?
- Why a charge in EF has energy?
- What happen if you put a test charge in the EF?
- Why would the field pushing it in the direction of field lines?
- Why positive charge has the greatest electric potential at the upper end of the field?
- Why it takes no work to move a charge perpendicular to the field?
- What is the relationship between atom and electricity?(think about carrying a mass horizontally)
- What is GPE depends on?
- What about EPE depends on?
- What is potential difference?
- What is volt?
Story-line/mini lesson / 13 min
The protagonist of our story is this guy: V= w/q
Last year, I mean in December, you guys have learned about conservation of energy. Now who can tell me what it is? For example, if 10 Kg stone sits on the edge of a cliff 10 meter above the ground. What would be the gravitational potential energy relative to ground? Good. Now let’s use that knowledge to understand another type of energy: electricity. Do you remember what symbol have you used for gravitational potential energy? Yes, it’s GPE. Now guess what symbol should we use for electrical potential energy? It’s V!!
GPE / V
We have to work against gravity to increase GPE / We have to do work on charge to move it against electric field.
Very weak force / Very strong force
Example: Let’s say you need to left a 10 Kg stone 10 m above the ground. How much work you have to do against gravity? / Example: Let’s say we want to move a positive charge from point A to point B in electric field. How much work we have to do?
To understand electric energy it is a good idea to first review gravitational potential energy (since we already taught them this topic) and figure out similarities between them.
Gravitational Potential Energy / Electric Potential Energy
/
If you hold a baseball up in the air, at the top, we can say that the object has maximum gravitational potential energy.If you drop the ball, it will eventually be sitting on the ground, we call it maximum kinetic energy. W=mgh / If you guys follow the same ideas that you did for GPE, you might see that there are similarities between the GPE and EPE. Lets say you place a positive charge near the positive plate in EF between two plates. Like the other one, we can say at the top we have Maximum electric potential energy. However, that charge does not want to be up there…so it will eventually accelerated down. While it is falling we know that the electric potential energy is being converted to kinetic energy. When it reaches the negative plate (its reference point) it has no electric potential energy remaining. It's all changed to kinetic energy. If you want to get the charge back up against the positive plate, you've got to do some work. As you do your work (W = ΔE), you are giving bac electric potential energy to the ball, until at the top it is back to having maximum electric potential energy. This change in electric potential energy depends on.
But this still doesn't explain what voltage is about: voltage, as we mentioned in the storyline, is the change in electric potential energy per unit charge.When we were talking about gravitational potential energy, it would sort of be like saying“How much work do I have to do to lift up something against gravity per kilogram.”Something that has more mass would need more work to be done to it.Now we are measuring the voltage... how much work is needed per Coulomb of charge. If
Something has more charge, it needs more work to move it.The unit for voltage could be given in J/C, but instead it is a derived unit called the Volt (V) in honor
of Alessandro Volta.This means that we have a formula for voltage that looks like this...
Student activities / 15 min
Building acopper-zinc-vinegar battery
Student will build a copper-zinc-vinegar battery, shown in the photo below. In this battery, the zinc is oxidized by copper ions from the copper strip. In this battery, the copper gradually migrates into the vinegar, and then replaces the zinc at the zinc electrode
Group presentation (1 group only) / 10 min
Any group can be candidate to make a classroom presentation. This group will receive extra point based on the following rubric:
Skills / E / G / O
Delivery (Presenter doesn’t rush, shows
enthusiasm, avoids likes, ums, kind ofs, you
knows, etc. Uses complete sentences.) / 3 / 2 / 1
Eye Contact (Presenter keeps head up,
does not read, and speaks to whole audience.) / 3 / 2 / 1
Posture (Presenter stands up straight, faces
audience, and doesn’t fidget.) / 3 / 2 / 1
Volume (Presenter can be easily heard by
all. No gum, etc. / 3 / 2 / 1
Content (Presentation shows full grasp and
understanding of the lab) / 3 / 2 / 1
Exit slip / 5 min
Exit slip: Exit slip is to be completed on a loose-leaf.
- What is one thing about electricity you learned most?
- What is one thing about electricity you learned least?
(There’re two) Handouts # II / 1 min
Home-work (Electrical energy)
Name:
Class:
Period:
Date:
Directions: Under the “Sample Sentence or Illustration” box, draw a picture that represents the vocabulary word or write a complete sentence that shows understanding of the term. (I will make a separate homework (easier) for my Student A because he is IEP.
- To check the charging voltage, connect a digital multimeter (DMM) to the positive (×) and the negative (−) terminals of the battery and select _____.
2. To check for ripple voltage from the generator, select _____
DC volt / AC volt / DC amps / AC amps
- The maximum allowable AC current in amperes that is being sent to the battery
.4 A / 1-3 A / 3-4 A / 10% of the rated output of the generator
Readings for tomorrow
Potential energy
Link:
Final remarks / 1 min
How many of you accept the null hypothesis, raise your hands.