Smaller rocks come from the breakage and weathering of bedrock and larger rocks. Many kinds of changes occur faster under hotter conditions. Materials may be composed of parts that are too small to be seen without magnification. When a new material is made by combining two or more materials, it has properties that are different from the original materials. For that reason, a lot of different materials can be made from a small number of basic kinds of materials.
Students investigate one interesting property of the mineral calcite.
They place a piece of calcite in vinegar and observe bubbles and fizzing. Finally the students look at the results of the evaporation for additional evidence of the presence of calcite in the four rock samples. Things that give off light often also give off heat. Heat is produced by mechanical and electrical machines, and any time one thing rubs against something else. When warmer things are put with cooler ones, the warm ones lose heat and the cool ones gain it until they are all at the same temperature.