Bioengineer and Stanford researcher Manu Prakash, known for his lab’s invention of the Foldscope, a paper microscope that only costs $1, has developed another inexpensive scientific device. The Paperfuge is a hand-spun, ultra low-cost, paper and string centrifuge that was inspired by the ancient whirligig toy. Wired shows us how it works.
Why is the paperfuge important? A standard centrifuge is usually a heavy, expensive, electricity-powered machine that spins around 20,000 revolutions per minute:
To test a person for diseases such as malaria, HIV, and tuberculosis, scientists spin samples of the patient’s blood, urine, or stool in a centrifuge. Thanks to centrifugal force, the spinning motion separates cells of different weights—such as pathogens in the blood—from the rest of the sample. Researchers can then look at the separated cells under the microscope to identify the disease.
In parts of the world that don’t have access to this kind of equipment, health workers might instead use the paperfuge. It can achieve 125,000 rpm and equivalent centrifugal forces of 30,000 g. Prakash explains, “Toys hide in them pretty profound physical phenomena that we just take for granted.” And these cost just 20 cents to make.
Related activity: Make your own whirligig with Science Friday.