HURRICANE DAMAGE

To learn about the story behind this game, please use the menu to the left.

Historical Note -- The Sponge Effect

Forests naturally protect against floods. The upper level of a tropical forest, the canopy, is a tapestry of intertwined branches and leaves which breaks the force of hard rain. After hitting the canopy, the rain trickles down 100 to 200 feet on lianas, vines, tree trunks and other foliage, gently arriving in the spongy undergrowth where it is absorbed. British biologist Norman Myers has called this the "sponge effect." The forest is like a giant sponge that absorbs the water and holds it in place where it is used by the same vegetation that is holding it in place. In contrast, where lands, especially steep mountainsides, have been deforested a hard rain drives directly into soil or rips through thin layers of vegetation. It is not readily absorbed and runs off causing erosion and mudslides. In late October, 1998, Hurricane Mitch devastated the recently deforested mountainsides of Nicaragua and Honduras, causing massive mudslides and killing over 9,000 people. Notable exceptions to the mudslide catastrophes were found on mountainsides that had national parks and forest preserves where the forests were intact.

A Historically Based Puzzle -- Hurricane Mitch

The current Difference to Inference puzzle will be based on the hypothesized tropical forest sponge effect. Let's say the dependent variable (DV) is the number of fatalities due to a hurricane that occur within a large area of land. The independent variable (IV) is whether that plot of land is forested or deforested.

There are 5 regions of a country, each one divided up into a 7 by 7 grid of 49 areas. Each area was either forested or deforested. A hurricane has just passed through the country in which these 5 regions are located. The shape of deforested areas is a little different from region to region and is shown in red. The areas in each region which are forested are shown in green.



Here's the puzzle. There are 5 different regions of the country. We have maps of the 5 regions showing the shapes of the deforested areas in red. But the records indicating which map goes with which region have been lost. You have helicoptered into one of the 5 regions. You know that one of the 5 maps applies to this region. Your job is to discover which map goes with this region.

Difference to Inference

Inference from Difference. You are standing in a field looking for the edge of the pattern which divides deforested (red) from forested (green) areas. To do this, use the Horizontal or Vertical Tool to collect samples of data on crucial adjacent areas. Use the data from the samples to decide if there is a difference in yield in the two adjacent plots. After you collect data a few times you should be able to infer, from the differences you find (or don't find), which of the 5 maps applies to the region you are standing in.

Seek the edge. Remember one of the fundamentals of human pattern perception: The important information is at the edge of the pattern.

Seek difference. Use the Horizontal Tool or Vertical Tool to determine if the of hurricane fatalities of any two adjacent areas are the same or different. If they are different, then you've found an edge of the pattern.

Differences that make a difference. One difficulty is that various deforestation patterns share the same shape on parts of their edges. Study the 5 maps noticing those crucial places where the shapes of the patterns are different. These places-where the 5 theories differ-are where you should put your attention and do your research. These are the differences that make a difference. These are the crucial differences at the edge.