How to Demonstrate Engineering Principles PostedNovember 4, 2014 UpdatedSeptember 25, 2017 Posted byJeff Lonnett http://www.youtube.com/watch?v=y6FmrOS72EA Learn how to demonstrate engineering, stability and gravity principles using marshmallows with the instructions in this Howcast science project video. Read More Average Ratings 5 Reviews0 Q&A0