Hobbies And Interests
Make Your Own Sedimentary Rock
Go out with your class to a nearby stream or field. Ask paired students to collect a handful of pebbles, sand and soil. Put the objects in sealable glass jars. Fill the jars with water, fix the lids and shake up the contents. Get each student to write down what happens during shaking and again when the contents have settled. Look for a clastic sedimentary rock type, characterized by a fragmented appearance, "clasts" -- the pebbles -- and a "matrix," which is the soil and sand surrounding the clasts.
Fossil Search
Sedimentary rocks often contain fossils. Fossils are exciting because they tell us clues about ancient forms of life. Find some examples of rock that fall into the main categories of clastic, chemical and organic. Look at the surfaces of each rock for fossils. Work out which of the three types of sedimentary rock contain the most fossils or whether they all contain about the same number. Find an example of a chemical sedimentary rock and ask students to write down how they think it was formed. Chemical sedimentary rocks aren't formed by sedimentation in the classic way but by the deposition of chemical elements that were dissolved in water.
Sorting Sediment
Ask the students to form teams with five members. Two members of each team must go outside and collect an assortment of different-sized pebbles as quickly as they can. About 10 each will be enough. They must hand their pebble collection to the remaining three members of the team, who then try to group the pebbles into size categories large, medium and small. They must work as fast as they can to create the three piles of pebbles. Each pile must be separate and neat, ready for inspection. The team with the best separation of different sizes has created the most clearly sorted sediment. Sedimentary rock can fall into both categories, but the one with the finest, best-sorted grain size will have traveled furthest.
Coal
Organic sedimentary rocks are made from organic materials, such as plant fragments. The common name for these types of sedimentary rocks is coal. A fun game you can play as a class involves the use of a music player, some lumps of coal and four large pictures of a coal-fired power station. Place each picture of a power station in a corner of the room. Give each student a piece of coal to hold. As the music plays, the students can run and stand on whichever power station they like. If the music stops and a student is stranded, he's out and has to take away his coal. Keep going until there is a winner -- the last remaining student. But, how much coal is left for the power station? Only one piece. Explain that coal is a valuable substance but that it's also non-renewable. The more we use, the less we have left in the future.