Igneous Rocks and Minerals - Presentation

The presentation on igneous rocks and minerals begins by setting learning objectives for students, which include describing the formation of igneous rocks, providing examples, and identifying their features. The informative session is framed around a documentary featuring Dr. Claudia Alexander, who explains that igneous rocks form when molten rock, either magma or lava, cools and solidifies. This process can occur inside the Earth's crust—forming intrusive igneous rocks like granite and gabbro—or on the surface as a result of volcanic activity, leading to extrusive igneous rocks such as pumice and obsidian. The rate at which the molten rock cools determines the size of the mineral crystals within the rock, with slower cooling allowing for larger crystals to develop.

Students are encouraged to engage with the material through a series of questions that recap the key points, such as the difference in crystal size based on the cooling rate and the examples of both intrusive and extrusive igneous rocks. They are also tasked with conducting research on igneous rock formation and characteristics, including a practical investigation into crystal size. The presentation covers the concept of minerals, the building blocks of rocks, and introduces the Moh’s scale of mineral hardness, ranging from soft talc to hard diamond. The session concludes by consolidating the knowledge gained, asking students to categorise rock samples based on their crystal size and to reflect on the properties of different minerals, thereby assessing their understanding of igneous rocks and minerals.