Holden: A significant impact

The claim of a legislative change to the value of the mathematical constant pi from 3.14159265358979323846 to 3 was an April Fool’s joke by Mark Boslough pub- lished in the April 1998 edition of NMSR Reports, the newsletter of New Mexicans for Science and Reason. The Indiana Pi Bill – or bill #246 of The last word the 1897 sitting of the Indiana General Assembly – was, however, a real attempt A signifi cant impact to use legislation to change a scientifi c fact. Despite its popular name, the bill was not about pi, but did assume incorrectly the value of pi as 3.2. chAnges in MAtheMAtics Are hAving A significAnt Patrick Moore played the Pluto April Fool’s joke in 1976 by announcing on BBC iMpAct on our dAily life, As STeVe hoLDen explAins. Radio 2 that Pluto was going to affect the Earth’s gravity and listeners would experi- ence a strange fl oating sensation, but sci- entists really did vote to demote Pluto in April Fools’ Day or All Fools’ Day will be it affects calculations of the mass of celestial 2006. Planetary scientist Andy Cheng criti- celebrated on 2 April this year as the result bodies and planets, and their orbits. cised the new defi nition requiring a planet of a variation in the calculation of the ver- Most notable of these was the downgrad- to have become round due to the force of nal equinox year, which is now measured at ing of Pluto from a planet to a dwarf planet, its own gravity, saying it was ambiguous, 365.24239 days. The variation means that following calculations by scientists from because it hasn’t answered the question: the standardisation of time in Australia that the US National Aeronautics and Space ‘how round is round?’ began when surveyors from the Australian Administration using the Alabama pi. The That’s simple, you just fi gure out the colonies gathered in Melbourne for the offi cial downgrade came when research- ratio of the circumference to the diameter, Intercolonial Conference of Surveyors on 31 ers voted at a meeting of the International or the ratio of the area to the square of the December 1892 will now be retrospectively Astronomical Union (IAU) in Prague, in the radius. dated from 1893. The variation requires the Czech Republic, in 2006, although that date It’s as easy as pi. changing of all historical dates relating to has now been amended to 2007. 31 December prior to this year. To be a full-fl edged planet, according This month’s Last Word was written a The recalculation is the result of a leg- to the new IAU rules, Pluto would need day later than fi rst thought after some islative change in the United States by to orbit the sun, be large enough to have hellish problems with deadlines for the the Alabama state legislature in 1998, become round due to the force of its own April edition by Steve Holden, Editor although that date has now been amended gravity and dominate the neighbourhood of Teacher, and a 2008 highly com- to 1999, when Alabama legislators voted around its orbit. mended winner in the Australian Council by a narrow majority to change the value Pluto has been demoted because it does of Deans of Education Excellence in of the mathematical constant pi from not dominate its neighbourhood. Nonethe- Education Journalism Awards in the 3.14159265358979323846 to 3. The sim- less, it will have a temporary gravitational ‘Print, Radio, Television or Online: Best plifi cation removed an irrational compo- effect that will reduce the Earth’s gravity commentary, opinion or critique’ cat- nent from mathematical calculation – since when the dwarf planet passes behind Jupiter egory for the Last Word. pi is an irrational number that cannot be on 2 April at 9:47am (AEDT). Pluto last did expressed as a fraction – with the change this in 1976, although that date has since Photo of planets that orbit the sun, are coming into effect fi rst in Alabama, then in been amended to 1977 as the result of a var- large enough to have become round due the rest of the United States and fi nally the iation in the calculation of the vernal equi- to the force of their own gravity and rest of the world. nox year. Readers can experience a strange dominate the neighbourhood around their A decade on and that legislative simplifi - fl oating sensation by jumping at precisely orbits by Patrick Wormsley courtesy of cation has now had a universal impact, since 9:47am (AEDT). T stock.xchng

66 t e a c h e r a p r i l 2009

Produced by the Australian Council for Educational Research (ACER), 2010 1