Understanding Water to Help the World

The unit began with investigating the question, “How much water is in the world?” Fourth graders used estimation, multiplication, and graphing to find the amount of saltwater, freshwater, and frozen freshwater available on the planet. Many students were surprised to see the vast difference between the amount of saltwater and freshwater on Earth. This realization led to discussions about the importance of conserving water and ideas about what people can do to create more freshwater since freshwater is an essential part of everyday life. A few students suggested that there should be a way to turn saltwater into freshwater because most water on Earth is saltwater. So, students looked into desalination and read articles about the desalination process. They analyzed its benefits and consequences to decide whether or not they believed California should build desalination plants to help with droughts. Most fourth graders thought the consequences of desalination plants outweighed the benefits and did not believe desalination plants were the best way to produce more fresh water. 

Additionally, fourth graders learned the different parts of the water cycle and how water cycles from the Earth’s surface to the atmosphere. They created simple models of the ocean and sky using cups, water bottles, and food coloring to see how these two systems interact. They learned vocabulary words such as evaporation, condensation, precipitation, runoff, aquifers, and watersheds. Students also learned about the impact of pollution on the water cycle. 

Currently, students are applying their knowledge of the water cycle and the states of water to engineer an inexpensive device that will collect clean water from fog to help areas that need access to fresh water. Students are working with a partner to use recyclable materials to design their devices. They will need to test their devices to see how much water they can collect and then evaluate ways to improve their designs through self-reflection and collaboration.