Report

Designing assessments for an edX course: a multi-stage approach Simona Socrate Principal Research Scientist, ISN Senior Lecturer, MechE, MIT Some underlying “philosophical” questions • Purpose of assessment exercises: – – – – – • reinforce comprehension of “lecture” material? promote critical thinking /problem solving skills? provide “connecions” to experiential learning? validate pedagogical approaches for the teacher? measure/certify mastery of material (for grading purposes)? Practical considerations: – what assessment approaches are feasible in a mooc? – cost/benefit of enhanced interface complexity: is it warranted? – what (sustainable) student workload meets course objectves? • Is what we are measuring relevant to the core pedagogical objectives of the course? Some challenges and opportunities of the mooc model • Challenges – Recast all assessment exercises to work with an automatic grader – Assess problem solving “methodology” with an automatic grader (sketches? procedure?) – Minimize operational barriers and sources of frustration • Opportunities – Large scale study on the effectiveness of alternate assessing approaches ( quantitative vs. conceptual exercises) – Emergence (the forum and the mind of the group) 2.01x A multi-stage approach • Stage 1: first release – Recast all assessment exercises developed in the residential MIT 2.01 course to work with an automatic grader • • • • • • multiple choice numerical answers numerical answers with unit selection symbolic answers MATLAB problem (x-y plotting and solution of linear systems of equations) graphic selection – Separate assessment exercises into • • • • Examples (inlined with lectures) Recitations (with instructor videos) Homework Problem (weekly, counting towards student grade) Quizzes (two quizzes measuring overall retention/comprehension, counting towards student grade) – Provide some plotting functionality and introduction to numerical methods by embedding MATLAB into some of the exercises Problem2 [15 Pts total] You need to indicate units in your answers for full credit The composite beam AB of length L=2 m, is fixed at B (x=L) and is composed of a round cylindrical core of constant radius R0= 1cm bonded inside a sleeve of thickness R0 (outer radius 2 R0= 2cm). q0 (x/L) y EO RO 2RO 3EO B x A L The beam is loaded by a downward linearly varying distributed load per unit length: !! !!! ! , with q0 = 2.76 KN/m as indicated. The material moduli are, for the core: EC = 70 GPa = E0 and for the sleeve: ES= 210 GPa =3 E0 (1) [2 pt] Obtain a symbolic expression for the bending moment M (x) in terms of L and q0. (2) [3 pt] Obtain a symbolic expression for the effective section stiffness of the beam (EI)eff in terms of R0 and E0 . Calculate the value of (EI)eff . (3) [2 pt] Obtain a symbolic expression for the curvature at the neutral axis, 1/r(x), in terms of L , q0 , R0 and E0 . Calculate the magnitude (absolute value) of the largest curvature along the beam and indicate its location. (4) [3 pt] Obtain a symbolic expression for the slope of the beam, q(x), in terms of L , q0 , R0 and E0 . Calculate the magnitude (absolute value) of the beam slope at the free end (x=0). (5) [1 pt] Set up the integral to calculate the vertical displacement of the beam, v(x), with appropriate bounds and boundary conditions. You do not need to solve the integral. (6) [4 pt] Calculate the maximum tensile stresses in the core and in the sleeve. Sketch the stress profile, sn(y), on the corresponding cross section of the composite beam. 2.01x A multi-stage approach • Stage 1: first release – Recast all assessment exercises developed in the residential MIT 2.01 course to work with an automatic grader • • • • • • multiple choice numerical answers numerical answers with unit selection symbolic answers MATLAB problem (x-y plotting and solution of linear systems of equations) graphic selection – Separate assessment exercises into • • • • Examples (inlined with lectures) Recitations (with instructor videos) Homework Problem (weekly, counting towards student grade) Quizzes (two quizzes measuring overall retention/comprehension, counting towards student grade) – Provide some plotting functionality and introduction to numerical methods by embedding MATLAB into some of the exercises 2.01x A multi-stage approach • Stage 1: Lessons Learned – Be very (VERY) careful with problem statements: rethink problems in terms of the grader capability – Pick and choose where you introduce complexity: make sure the additional barrier for the student is NECESSARY for pedagogical purposes – Online students are (for the most part) understanding and appreciative. Be honest and apologize/correct as needed – Accept the fact that the mooc teacher is on a (steep!) learning curve as well: perfect is the enemy of good 2.01x A multi-stage approach • Stage 2: second release – Introduce Conceptual Problems – Extend MATLAB functionality to enable “design” problems • Stage 3: third release – Introduce a graphical interface (similar to the circuit interface in 8.02x) for structural elements – Embed a numerical (Finite Element) structural solver. – Enable direct peer feedback? Do NOT forget the “philosophical” questions • Purpose of assessment exercises: – – – – – • reinforce comprehension of “lecture” material? promote critical thinking /problem solving skills? provide “connecions” to experiential learning? validate pedagogical approaches for the teacher? measure/certify mastery of material (for grading purposes)? Practical considerations: – what assessment approaches are feasible in a mooc? – cost/benefit of enhanced interface complexity: is it warranted? – what (sustainable) student workload meets course objectves? • Is what we are measuring relevant to the core pedagogical objectives of the course?