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Floods and Science
The water in my part of the country is everywhere this year. The Mighty Missouri River has gone wild. My students are fascinated by the power of water and seem to be amazed at how much damage a flood can cause. This will be a great year to insert some flood science into any course.
First we need to understand a bit about water. One cubic centimeter (a bit about the size of the tip of your little finger) is 1 gram. There is an old saying that “a pint is a pound the world around”. Kids do not seem to realize that water has quite a bit of mass. I love to give the kids a 5 gallon bucket and fill it till it is really difficult to lift. At that point you can introduce volume and mass measurement.
The idea of water having a mass that can be determined “by only knowing the volume is a big idea. The doorway to that idea is the surprise that water is so heavy.
This will really tell my age, but, I remember when waterbeds we ‘re very popular. The apartment or house you lived in had to have flooring that was heavy duty enough to support a waterbed. Think of the mass. A water bed is about 3 meters by 2 meters by .3 meters. So the total volume is 3 x 2 x .3 = 1.8 cubic meters. Since 1 cubic centimeter is 100 cm x 100 cm x 100 cm or 1 000 000 cubic centimeters or milliliters, and since 1 ml = 1 gram the water in a waterbed will weigh 1 million grams or 1 000 kilograms. This is a good metric conversion discussion point.
1 kilogram is about 2.2 pounds. That means that the average water bed is the same as about 14 students in mass. Water is heavy.
The current rate of flow of the Mighty Missouri is about 175 000 cubit feet per second. That is a lot of water and a lot of mass. The flow curreltly is 579% higher than normal flow. Now we add the river system. The river is actually the combination of list of land drainage….lots of land. The Missouri is the river that drains water from 530 000 square miles in the Great Plains, Rockey Mountains, ten states and two Canadian Provinces. Along the river there is a system of earthen embankments called levees that protect towns and farmland from when the river goes outside the banks. These levees have to hold a lot of water and a lot of mass. An understanding of the mass of water leads to a new appreciation of just how strong these levees have to be.
The river is also a good place to begin understanding topographic maps. There are lots of good web sites for topographic map lessons. My favorites come from the USGS and sir-ray.
I taught topographic maps a few years back and my students were fascinated by the maps and enjoyed finding their houses on the maps and figuring out what level of flooding we would need to have water reach their homes. Today that becomes real, as there have been some overtopped levees and the students will pay attention to new evacuation orders. We will archive photos and memories as we go along and with a little luck the levees will hold and the memories will be of a close call and not a catastrophic flood.