Slipper Abacus | Punjabi
Channel: Arvind Gupta
Date: 12/04/2016

You can make teaching aids using old rubber slippers or flip-flops. You will need an old slipper, punch, hammer, 3-pencils and a few beads.  Hammer the punch to make three holes in the rubber slipper on its mid-line. Stand three pencils in these holes. Though it will look like a pencil stand but it is actually an abacus. Now place one bead in the right end pencil which represents the UNITS place. This bead will represent ONE. Add another bead to show two. You can place only 9 beads in this pencil. There is no place for the tenth bead. The nine beads represent number 9. If you place one bead in the middle pencil which is in the TENTHS place then the abacus will show the number 19.

Six beads in the right end UNITS pencil represent number 6.  Five beads in the middle TENTHS pencil represent 50. Four beads in the left hand HUNDRETHS will represent 400. Next the abacus shows the number 214. Then is the number 403 with no beads in the tenth’s place. 

Now hold the slipper by its two ends and bend it downwards. You will be surprised to see that all the three pencils meet at a point – on a focus as happens in a concave mirror. If you bend the slipper upwards all the three pencils will move away from one another – they will diverge as in the case of a convex mirror. This model comes in very handy to show RAY DIAGRAMS. In case of a PLANE mirror the rays return back the same way. In a CONCAVE mirror they converge. In a CONVEX mirror rays diverge. A simple humble old rubber slipper helps us the get a concrete feel of what a concave or convex mirror does to rays. 

Dubbed in Punjabi by Sumeet Gupta TATA Trust: Education is one of the key focus areas for Tata Trusts, aiming towards enabling access of quality education to the underprivileged population in India. To facilitate quality in teaching and learning of Science education through workshops, capacity building and resource creation, Tata Trusts have been supporting Muktangan Vigyan Shodhika (MVS), IUCAA's Children’s Science Centre, since inception. To know more about other initiatives of Tata Trusts, please visit www.tatatrusts.org