Had when i worked in a preschool and kids love them! I would use colored sand instead of white salt. DIY salt tray with alphabet cards. Easy to make and kids have fun smoothing out the salt after correctly making the letter
Possible school experiment to show importance of wetlands/riparian zones! This shows the importance of plants in our soil. Plants like trees and grasses help purify ground water. Without them the ground water gets polluted and harder to clean and drink.