The 4-H Rock Sandwich Project is a special interest program presented on demand in schools and in 4-H clubs. It is a lesson on the three types of rocks, minerals and rock formations.
Harlan County 4-H Agent Raymond Cox recently presented a lesson to the fourth-grade classes at Evarts Elementary School on sedimentary, igneous and metamorphic rock formations. The building blocks of rocks, minerals, were defined and the Mohs’ scale of mineral hardness from one to 10 was discussed, with talc being No. 1 and diamond No. 10.
Students learned that fluorite, with a hardness of four is used in tooth paste and other dental processes to help prevent tooth decay. Quartz with a hardness of seven was used to go on the end of arrows years ago. Students discussed the formations of rocks seen in Harlan and made visible through mountain road cuts.
This all leads up to making a sandwich representing those rock formations. First, the wheat bread represents sandstone; the second layer, strawberry jam, represents fossilized limestone; the third layer, brown bread, represents mud and shale; the fourth layer, crunchy peanut butter, represents conglomerates and pebbles; and the fifth layer, white bread, represents chalk and powdery substance.
Students then were able to answers questions about the lesson including sedimentary, metamorphic and igneous rock, rock formations and minerals. They also enjoyed eating the sandwiches they made. The cafeteria supplied juices.