Step V: Group the students give them questions or topics to work on and ask any member to share their ideas with the rest of class
Step VI: Teacher illustrates the constructions on the topics on the board for the students.
Step VII: Teacher ensures that the students follow the demonstration.
Step VIII: Teacher gives the students room to ask question.
Evaluation: Students are to work on the construction of ellipse and cycloid as illustrated in the procedure above.
Conclusion: Teacher emphasizes on the each student error and allows the students to correct their errors.
WEEK FOUR Date: Monday 25th – 29th September; 2023.
Class: SSS 2
Subject:TECHNICAL DRAWING Topic:LOCI CONT’D Sub-topic: Construction of Epicycloids, Hypocycloid and Archimeclean Spiral
Duration: 120 minutes
Learning Objectives: By the end of the lesson, students should be able to:
Construct epicycloids
Construct hypocycloid
Construct Archimeclean Spiral
Reference books: New Element of Technical Drawing by Osuji, U.S.A and Akano, E.O.
Period: 1, 2& 3 Opening THE EPICYCLOID This is the locus of a point on the circumference of a circle rolling around the outside of a large circle without slipping.
To construct an epicycloids given the radius of the rolling circle = 21mm and radius of the large circle = 50mm
Procedure: Draw the rolling circle radius 21mm centre at O
Divide it into a number of equal parts e.g. 12 equal parts.
Draw the large circle with radius 50mm centre at O1 and tangential to the rolling circle.
Make the arc of the large circle be equal to the circumference of the rolling circle using or using the angle subtended at the centre i.e.
Divide the arc into the same number of equal parts.
Centre at O, project arc, from the divisions of the rolling circle and equal to the large arc.
Radiate lines from O, passing through the divisions on the large arc.
Radius of the rolling circle, centres at the points of intersection of the radial lines and central arc, cut the corresponding arcs from the rolling circle.
