November 28, 2023: An ancient art form is upending what we think about math, air pollution has surprising health effects and the frequent intersection of science and society. —Andrea Gawrylewski, Chief Newsletter Editor | | | The people of Vanuatu in the South Pacific Ocean have likely used "sand drawing" for thousands of years, as a communication and storytelling tool. Traditionally, it consists of a person drawing a continuous, closed line with their finger in beaten earth, sand beaches or ashes. New research shows that these artworks can be modeled mathematically, using algorithms and algebra. Sand drawing connects clearly to what mathematicians call graph theory, particularly Eulerian graphs: these drawings are made on a grid, and an artist must go from node to node of the grid without crossing the same path or cutting the grid other than at its nodes and they must return to the starting point without lifting their finger.
Why this matters: Before scholars first proposed the link between sand art and mathematics, they generally assumed that only societies with writing could truly practice math, ignoring many other practices seen in societies with oral traditions that did not use a written language. In the last 100 years, researchers have discovered mathematical applications in several traditional cultural practices. Some educational researchers are investigating whether the practice of sand drawing could support mathematics instruction in schools.
What the experts say: "Before the arrival of the tuturani [the white foreigners], the people of northern Pentecost did not know how to speak," says Jief Todali, a chief in the Raga region of Vanuatu. "They expressed themselves through drawings that they traced on the ground with their fingers. Instead of people, the rocks, the stones, the ground of the hills and valleys, the wind, the rain, the water of the sea spoke." | | | A sand drawing evokes a fish hiding under a stone to escape a predator. Credit: Alban Da Silva | | | Particulate matter pumped into the air by cars, factories, woodstoves and wildfires causes nearly nine million premature deaths a year, with South Asia bearing the highest tolls. This particulate matter is called PM 2.5 because it is small enough to enter the bloodstream and lodge in the lungs where it causes respiratory problems, and has also been linked to diabetes, obesity and dementia. An estimated 460,000 deaths in the U.S. were attributed to coal-fired power plant pollution between 1999 and 2020, new research finds. Surprising effects: Particulate matter can have unexpected health consequences as well, including: Cancer: Airborne pollutants increase the risk of breast cancer and have been tied to liver, pancreatic, prostate, lung and ovarian cancers. Small babies: Women in northern Europe exposed to PM 2.5 and other air pollutants give birth to smaller babies. Fine particles can penetrate the placenta and affect the exchange of oxygen between the baby and mother. Suicide: The number of suicides goes up in rural U.S. counties on days with wildfire smoke in the air.
What the experts say: "We are finding out that particulate matter affects almost every aspect of our bodies and minds, from cognition to our heartbeats to our skin," says Christa Hasenkopf, an air-quality data expert at the University of Chicago. | | | Just one U.S. reservation hosts nuclear weapons. This is the story of how that came to be. In a tale that captures the troubled relationship between Native Americans and the U.S. government, host Ella Webber, a member of the Mandan, Hidatsa and Arikara Nation in central North Dakota, digs into a decades-long mystery: how 15 intercontinental ballistic missiles came to be siloed on her ancestral lands. As part of efforts to modernize and update the U.S. arsenal, the federal government wants to take the old weapons out and replace them with new ones, and it's unclear how many people living there know about it. Listen now to our five-part podcast series. | | | • Firearm forensics has recently faced criticism for its questionable reliability. But firearms examiners are remarkably accurate when they identify casings and bullets, write attorneys Nelson Bunn and Raymond Valerio, citing several recent studies. "Firearms identification evidence is scientifically sound and withstands rigorous testing in the crucible of the courtroom," they say. | 5 min read | | | The host of the podcast I'm featuring above is 20 years old and a junior at Princeton University. I highly recommend the full series. It's part of our December special report, "The New Nuclear Age," on a $1.5-trillion effort to remake the American nuclear arsenal. The physics and engineering of nuclear weapons are hard sciences, yes, but like many branches of research they come with powerful societal implications. Science does not happen in a vacuum, as Ella will show you. | —Andrea Gawrylewski, Chief Newsletter Editor | | Subscribe to this and all of our newsletters . | | | | Scientific American
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