To introduce the study of how rocks form and change, students use magniﬁers to observe specimens of a rock (granite) and the minerals it contains (feldspar, quartz, and mica). They then observe a variety of rock samples from home. Students learn that the three basic rock classiﬁcations, igneous, sedimentary, and metamorphic, describe how a rock was formed.
Learn by Reading
For additional content-area reading, check out the Houghton Mifflin Science eBook: Grade 4, Unit C, pages 6–7.