Q1.
Find out more about such simple technological inventions that improve access to medical care in remote places.
Answer
The paperfuge is one of a whole family of frugal medical devices: they use everyday materials and no electricity, cost very little, and can be carried to a village that has neither a laboratory nor a reliable power supply.
| Device | How it works | What it makes possible |
|---|---|---|
| Paperfuge | A cardboard disc on twisted strings, like a button whirligig; spinning it at very high speed separates blood by centrifugation | Detecting malaria and anaemia without electricity |
| Foldscope | A microscope folded from a paper sheet with a tiny glass lens | Seeing microbes and blood cells in the field, at very low cost |
| Paper-strip diagnostic tests | A drop of blood or urine travels along treated paper by capillary action and changes colour | Instant tests for pregnancy, malaria, diabetes and infections |
| Solar-powered vaccine carrier | An insulated box cooled by a small solar panel | Vaccines kept cold on the way to villages with no power |
| Jaipur foot | A rubber and wood artificial limb made by hand from local materials | Affordable mobility for people who have lost a leg |
Why the paperfuge works: A laboratory centrifuge is only doing one thing — spinning a tube fast so that the outward force on each blood component is far larger than its weight, driving the heavier red cells outwards and leaving the lighter plasma near the axis. Nothing in that idea requires a motor. A disc whipped by twisted strings can reach speeds of many thousands of revolutions per minute, which is enough to do the same separation in a few minutes. The physics is unchanged; only the cost has been removed.
Try this: Make the button-and-string whirligig of Activity 5.8 and watch how a disc can be driven to a very high speed simply by pulling the strings in and out.