Background:

Sedimentary rocks are made of sediments, eroded pieces of other rocks that are either compacted, cemented or crystallize after the water has evaporated from a solution. Compaction happens when water is squeezed out of porous sediments like sand and clay by layers of sediments that have piled up on top of them. Cementation occurs when minerals in solution like calcite, quartz or iron oxide seep in spaces between pieces of rock and precipitate to form natural glue.

Objective:

To distinguish between detrital sedimentary rocks that are formed by compaction from ones formed by cementation.

Materials :

1. Lab Apron
2. Salt
3. Plaster of Paris
4. Safety goggles
5. Sand
6. Pebbles
7. Scissors
8. Water
9. Three 6 oz paper cups
10. Hand lens
11. Teaspoon
12. Disposable stirring sticks