today must be the first day in a long long time when my background came out of me naturally, though in words i must admit i would have a better job that i could do with.
i decided to get the boys from 5c to finish this last nagging question that they left blank in the science workbooks. the unit was on simple machines, and the very last part was on - guess what, gears!
unbeknownst to certain powers; before recess ended, i took my bicycle up to the classroom; and placed it at the back. i had only enough time to pick up my waterbottle and my school laptop before that bell went off; and to the courtyard i went.
i brought the boys up, and i showed them
this flash animation (right click and save; or
try this url instead) for an introduction to the lesson i was about to have. the boys had a ball of a time!
after the video ended, i gathered the boys to the back of the class; where i did a basic explanation of gears using my bike. hey, nothing wrong about using my personal items to teach boys, right?
then back to the question in the book. the question was about using one input gear, a 10t gear turning anticlockwise, and the resultant effect must also turn another identical 10t gear, not only 3x faster rotation, but also in the
same direction! i cajoled the students, led them to deduce the answer, and voila! one of them indeed caught the idea, and used the concept of using two gears fixed to each other on the same axle! mission accomplished! then another boy,
spencer, asked if we could mesh (another word i taught them today, nevermind if most adults relate that to filtering/fashion etc) the input gear direct to the large 10t/30t combination gear; to take away the need for the idler gear. hey! this class IS smart! even one of the boys who i'd thought was naughty, was caught in the moment, got enlightened by the design; and was totally immersed in the lesson. i couldn't feel any better, i must say!

when i was drawing the sketches of the gears, some boy(s) said it looked like a planet, and BAM! i told them there existed the planetary gearset - betcha didn't know it, i learnt about it in my national service days as a vehicle mechanic.

i just hunted a few more sites for idler gear information, it may be useful in the future. in fact, one of the sites mentioned that idler gear usage would usually lead to more advanced designs. wow!
http://conexiones.asu.edu/pdfs/idlergears.pdf http://www.rec.ri.cmu.edu/education/testpage/idler.shtmlhttp://www.cpes.vt.edu/lego/files/gears.pdfhttp://scnc.bas.k12.mi.us/~mms/Lego/Gears%20and%20Speed%20wo%20answers.pdfwho says you can't use your daily transportation to teach students something in the syllabus?
