PLANNING THE LESSON/SUBTASK: Part 1
Date: Feb 20, 2014 Grade: 12U Physics Timeframe (time available): 75min
Title of Unit : Electric Charges and Electric Fields
Session 7.5:The Millikan Experiment: Determiningthe Elementary Charge
describe and explain, in qualitative terms,
the electric ﬁeld that exists inside and on
the surface of a charged conductor
(e.g., inside and around a coaxial cable); / describe instances where developments in technology resulted in the advancement or revision of scientiﬁc theories, and analyse the principles involved in these discoveries and theories (e.g., analyse the operation of particle accelerators, and describe how data obtained through their use led to enhanced scientiﬁc models of elementary particles);
explain the roles of evidence and theories in the development of scientiﬁc knowledge
related to electric, gravitational, and magnetic ﬁelds
Connections to Equity, Diversity, And Social Justice:
Cross Curricular Connections / Connections to Students’ lives: (local/global)
Diagnostic (assessment forlearning) x Formative (assessment for/as learning) Summative (assessment of learning) x
Observation Presentation/Performance / Group Work / Presentation
Accommodations and/or Modifications / Differentiated Instruction:
Instructional Environmental Assessment
Increase/Decrease time, amount / Set up the classroom for group work, with material stations along the walls
Teacher Resources Human Resources Student Materials Equipment
Textbook / White boards;
Envelopes with screws;
Electric scales. / Laptop; projector;
DELIVERING THE LESSON/SUBTASK - Part 2
*Grouping: W = Whole class; S = Small group; I = Independent
Timing / Grouping / Questions to ask: What is an electron? What is its charge? / Materials/
Envelopes with various numbers of screws; electric scales;
W / S / I
15 min / x / Mental Set (hook):Whole Class Discussion
White Board Activity; groups of 5 (15min)
Things to know before hand:
Free body diagram
45 min / x / x / Body: Group and Independent Practice; Investigation Skills
- Theory talk: How to determine the mass of a single screw (5 min)
- The class is divided into groups of 3 (note taker, facilitator and collaborator), each group will perform Peter Clifford's Drywall Screw Experiment–using the envelopes provided and an electronic scale to find the mass of a single drywall screw. (20 min)
- YouTube Video:The Millikan Oil Drop Experiment (15 min)
- Q&A about the video (5 min)
15 min / x / x /
Closure(sharing the learning in some way):Group Exit Card see end of this lesson plan
x / Homework/ Reminders:
Text book questions at the end of session 7.5
Reflections: Include Successes, Challenges, Changes, Next steps
Group Exit Card instruction: Think Pair Share, think about how you would solve this question, share your idea with another student and discuss your methods, then write your solution as a group.
An oil drop, of mass 4.7×10-15 kg, is suspended betweentwo parallel plates, as in figure above.
(a)Calculate the charge on the oil drop.
(b)Calculate the number of elementary charges requiredto make up this charge.
(c)Does the oil drop have a deficit or excess of electrons?Explain your answer.
A note on Clifford’s Drywall Screw Experiment
This could be used as a substitute for Robert A. Millikan’s oil drop experiment. A set of envelopes is created with different numbers of drywall screws in each. There is A relationship between the techniques done in this experiment and the oil drop experiment. There is no difference of one drywall screw between different envelopes. Finding the mass of the single drywall screw is the intent.