If you go on the internet you will find lots and lots of suggestions about making a Crystal Garden. I consider this one better than most.
In it's 6 pages you will find a Teacher Page with generalizations, objectives and resources. Three (3) Student Activity pages (with illustrations) outlining the various steps taken to make a salt crystal garden. It ends with a Student Observation Record sheet asking students to record changes in their crystal garden over a five day period.
Using the NGSS outline this activity falls under PS1.B - Chemical Raction. Using the Common Core Standards for Math this activity falls under Measurement and Data
John F Gardner
The Environmental Ed Guy