Coal is formed by decaying plants. Power plants use it to generate electrical power, and it is used to make cement and steel. Coal is also an ingredient in the materials to make tennis rackets, mountain bikes and shampoos. The chalk students use to write on sidewalks and that is used in construction is another type of sedimentary rock. It is white because it is made up of colorless skeletons of plankton. The White Cliffs of Dover in England are an example of a natural land form consisting of chalk.
Another sedimentary rock children will be familiar with is salt -- or halite -- because they have probably used it to season their food. It can also be used on highways to melt snow. Sandstone was a popular building material in ancient times. It has been used to construct homes, temples and statues. Some types of shale can be broken down to allow oil and natural gas trapped within to be collected and used to power cars and heat homes.
Limestone most commonly forms in ocean waters. It is an important component of cement and is used in many building projects. In fact, the Great Pyramids of Giza and the Empire State Building are constructed of limestone. Gypsum is another rock used in construction. The plasterboard found in walls and ceilings often contains gypsum. It can also be found in food, toothpaste and fertilizer. The fake snow seen in old movies such as "The Wizard of Oz" was frequently made from gypsum.
Conglomerates are a common type of sedimentary rock formed by smaller rocks and particles becoming glued together with sand and mud. They have limited uses as they don't break cleanly, though they are sometimes used in jewelry or as decoration. A famous example is Montserrat near Barcelona, Spain. The mountain is also Spain's first national park. Flint -- or chert -- was commonly used to make arrowheads and other weapons from the Stone Age to the 1800s. When struck against steel, it creates a spark, so it has been used to start fires and as part of the mechanism to fire early gun models.