Variations on above topic. It is thought that some species of periwinkle orient their movements with light. Snails will crawl around out of water and may head in a certain direction. Students hypothesize, design and conduct experiment, write up, discuss advantages of light orientation to periwinkles if orientation is found to be present. Students hypothesize, design and conduct experiment, write up.
Students can easily measure centimeters of travel per minute as a dependent variable.
Ten periwinkles are placed on a piece of tinfoil for a known period of time in each experimental regime. The snails will crawl around, leaving mucus tracks. The length of the tracks can later be measured and cm traveled per minute can be calculated. Periwinkle vertical position lab . Periwinkles in a tank and in nature may adjust their position to remain just above the waterline.