Project Cornerstone Visits 5th & 6th Graders at Rohr Elementary

Written by Alyssa Burley.

On January 20th, 2016, Project Cornerstone visited with 56 students at Rohr Elementary School in Chula Vista, CA.

The 5th and 6th grade students from Ms. Gurrero's and Mr. Talbot's classes participated in Project Cornerstone's lesson on construction aggregates (i.e., sand, gravel and crushed stone) used in building materials like concrete and asphalt products.

The two classes learned how construction aggregates are used to build homes, roads, bridges, schools, etc. in the community, and where the materials are naturally found throughout the county.


Each student developed a hypothesis for which type of sand (i.e., river or beach) they thought was best for making concrete based on what they learned in the lecture and their own observation.  Then, in small groups, the students used a sieve and scale to analyze the two sand samples.  Looking at the data collected, the students determined river sand is best from making concrete.

After completing the sieve analysis, one student excitedly said, "I want to do this everyday!"  Another student said with a giant grin on her face, "Yay! We did this last year."


Students then made their own concrete using the correct proportions of sand, gravel, cement and water.  They witnessed first-hand the hydration process which transforms the liquid concrete mixture into a solid building material.

Photos by Alyssa Burley