Hobbies And Interests
The Basics
Gather up sand, gravel, dirt, and other powder-like substances like chalk and limestone. You will also need glue or plaster, cups and stirrers. Pour one of the sediments into the cup and cover it with a layer of glue or plaster. Stir the mixture and form another layer by adding a sediment and glue. Stir only the most recent layer. Try not to disturb the layer underneath. Continue until the cup is full. Once the glue and plaster dries for 10 to 20 minutes, you will have a sedimentary rock to study. You may have to rip the cup away, so use a disposable one for the project.
Additional Lessons
Give the first graders an idea of what really happened when the sediments were made long ago. Add fossils to your rocks by placing small leaves, twigs, shells and other items into each sediment. Once the rock has dried overnight, you can teach a lesson on erosion by sanding the "rock" or exposing it to running water.
Rocks in a Bottle
You can simulate sedimentary rock in a bottle by adding different colors and textures of powder sediment to a water bottle. Fill the bottle half full. Do not mix the glue or plaster between layers. Instead add water. This project will produce a "rock" of sorts that the students can observe. It is also a project that is quicker and easier to accomplish with a room full of seven-year-olds.
Completing the Lesson
Let the students experiment with not only the types of sediments they create, but also the ratio of liquid to sediment in each project. Talk about the effects of more water, versus less. Let the sediment projects sit in the classroom for observation for a few days to a week. The children will begin to see how the settling effects of time contributed to creating the sedimentary rocks.