Types of Rock
Know the three main types of rock — igneous (formed when lava or magma cools), sedimentary (formed from layers pressed together), and metamorphic — and that fossils are found in sedimentary rock
Lesson
Set out your lesson
“Rock groups describe how rocks form, not just how they look. Igneous rock forms when molten material cools. Sedimentary rock can form from compacted and cemented sediment, or by other routes such as mineral precipitation. Metamorphic rock changes under heat and pressure without fully melting. Fossils are most commonly preserved in sedimentary rocks. Safety: No mineral samples, dust, heating, or pressure tools needed. Stop: Stop after the paper sort. Do not heat, crush, hammer, or collect rocks.”
Bring to the table
- Paper
- Pencil
- Six torn paper cards
Extra for the adult
Worked example. Card E belongs under Metamorphic. Answer: the rock changes while solid, so it is not a new igneous rock formed from cooling melt. A fossil in sedimentary rock can survive because burial preserves evidence; layers themselves do not guarantee a fossil.
Optional challenge. Explain why two rocks with stripes might have different formation histories and need more evidence.
What to notice. Keep the sort and explanations. Note help reading the supplied formation clues; this is not independent identification of natural specimens.
Share and support
Family records and proof options
Keep a record of your learning
Save photos, notes, and attendance. Export a proof packet for compliance or portfolio reviews.
Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
National Park Service · Practice link — not the full lesson
Rocks and Minerals
Before you open · source notes
Rocks and Minerals supports Types of Rock. An adult previews and guides; this is a learning page, not a scored quiz.
Free educational page, no sign-in required for the tested path.
Before you openAsk the learner one fact they learned and one question they still have.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public National Park Service page. An anonymous GET on 2026-11-12 returned HTTP 200 with no login or payment prompt for this URL. Opening the link does not save practice or assess mastery. An adult should preview and guide the learner.
National Park Service. “Rocks and Minerals.” External page; Gakuva does not copy, host, embed, or redistribute materials.
Unknown — link only
Check understanding
- Name the three main rock types: igneous, sedimentary, metamorphic
- Explain that igneous rock forms when lava or magma cools and hardens
- State that fossils are preserved in sedimentary rock because it forms in layers
“If your child finds different rocks on a beach walk, can they sort them and explain that some formed from cooled lava, some from layers pressed together over time, and that fossils are found in the layered ones?”
Curriculum record
- Type
- Conceptual
- Subject
- Science
- Domain
- Volcanoes & Earthquakes
- Age range
- Ages 7–10
Standards