NGSS asks students to learn about cell organelle structure and function. Students have a difficult time visualizing the parts of the cell because they are so small. This lab uses de-shelled eggs to represent cells on a scale that all can see and understand. The membrane of an egg is semipermeable just like that of a standard plant or animal cell. By putting the eggs in different solutions, students can observe whether water is drawn into or out of the "cell" through osmosis. Eggs that have been placed in solutions that have a higher concentration than the inside of the egg will expand in size and will "pee" when pricked by a pin. Set the kids into a competition to create a solution that will make an egg "pee" the most and "pee" the least. They will have so much fun with this lab while they are learning about the structure and function of the cell membrane.