Studying the effects of flood waters can teach people how to better prepare for and possibly prevent the resulting devastation. Children of all ages and grade levels can explore the science behind one of nature's most awesome powers with age-appropriate school projects. The following projects are intended for elementary and middle school students. Do not attempt them without adult supervision.
Find out which material holds back flood waters the best. Get three socks, fill one with sand, another with soil and the last with gravel. Drill a 1/2-inch hole in the bottom of an ice cream bucket and position the bucket over a measuring cup. Place a sock inside the ice cream bucket so it covers the hole and pour in 2 liters of water. After one minute, record the water level in the measuring cup. Repeat with the other two materials.
Find out how much water different soils can hold before they flood. Gather 10 soil samples from around your neighborhood, place each one in a small Styrofoam coffee cup and label its location. Screen and weigh each sample to determine the proportion of fine material to course material in the soil. Place the soil back in its cup and gently compact the soil so that it fills the cup to the line just below the lip. Next, starting with 1 liter of water in a measuring cup, pour water into a soil sample cup until the water comes to the brim. Measure how much the soil absorbed by subtracting the remaining water in the measuring cup. Repeat with all samples.
Determine how much water an earthen dam can hold back before failure. Using a rectangular plastic swimming pool as a flood table, build an earthen dam with soil from your yard. First, screen the soil to determine the amount of fine material to course material. Build an earthen dam across the pool a quarter of the way from one end. The dam should be 8 inches wide at the base, 2 inches wide at the top and 6 inches high. In 1-liter increments, add water to the large "flood" area until the dam fails.
Find out what materials prevent erosion the best. Prop one end of a 6-foot length of roof gutter on a box and the other end over a measuring cup. The end over the measuring cup should be about 6 inches lower. Coat the bottom of the gutter with an even layer of sand. Pour 3 cups of water into the gutter on the high end, wait five minutes and record the water level in the measuring cup. Dump out the measuring cup and clean out and dry the gutter. Repeat with mixtures of sand with fine gravel, sand with course gravel and sand with fine and course gravel. The smaller amount of water in the cup, the better the material prevents erosion.