Mathematics and Society - OS X Lion Server

DOUBLING 24816(When numbers keep doubling, they get very large after a few doubles. The population"bomb" is doubling faster and faster (see chart). But resources are dwindling, foodproduction is falling behind and technology is unable to provide "answers" like ediblealgae and solar power at a fast enough rate. Unfortunately, the doubling time is evenshorter in some of the poorest countries, leading to the likelihood of mass starvation.(It is estimated that 10,000 people die ofstarvation every day even now.) One groupWorldDoublinghas calculated that earth can support only Date population (est. ) time3.5 billion people at a reasonable standard1650 500 millionof livingl Although you may choose not todeliver such gruesome information to your 1830 1 billion180 yearsstudents, you can perhaps impress on them1930 2 billion100 yearsthe size to which doubling numbers canreach in a small number of doublings, and 1975 4 billion45 yearsthe necessity for slowing popplation growth. 2010(proj .)8 billion35 years1)1Clear the desks from about 4 of the room. Have 1 student stand in the clearedspace, then 2, then 4, then 8, etc. As students are added, have the class noticehow quickly each person has uncomfortably little room. (Adjust the amount ofcleared space if you have a small class or an unusually large room.) Since wehave only so much livable space on earth, the same overcrowding will eventuallyhappen if pur population keeps doubling.(2) (From The Limits to Growth, Meadows and others.The following is also shown in a movie of thesame title.) "Suppose you own a pond on which awater lily is growing. The lily plant doublesin size each day. If the lily were allowed togrow unchecked, it would completely cover thepond in 30 days, choking off the other forms oflife in the water. For a long time the lilyplant seems small, and so you decide not to worryabout cutting it back until it covers half thepond. On what day will that be? On the twenty-ninth day, of course. You have oneday to save your pond." Many students will think the 15th day. If your students arenot familiar with a lily plant, you might want to substitute something like weeds ina flower patch, junk on a playground or flies ("Kill a fly in May-you'll kill amillion a day. Kill a fly in June-not a day too soon. Kill a fly in July and youjust kill a fly"). A sequence of transparencies with dots for the lily plants (or (weeds, junk or flies) can make an effective demonstration.194 Permission to use granted by Universe Books