Plate Tectonics and Evidence
Grade 8 · Science · Earth and Space · Alaska, USA
Lesson Summary
Understand how Earth's plates move and the evidence that supports this theory.
Explanation
Earth's outer shell is broken into large pieces called tectonic plates that slowly move over the mantle beneath them. This movement causes earthquakes, volcanic eruptions, and mountain formation. Evidence for plate tectonics includes the jigsaw-like fit of continents, matching fossils found on separate continents, similar rock layers across oceans, and the pattern of seafloor spreading at mid-ocean ridges. Alfred Wegener first proposed continental drift, and modern technology has confirmed and expanded his ideas.
Practice Questions
Q1: What happens at a convergent plate boundary?
Answer: Two plates push toward each other, which can form mountains, cause one plate to slide under the other, or trigger earthquakes and volcanoes.
Q2: How do matching fossils on different continents support plate tectonics?
Answer: Finding the same fossils on continents now separated by oceans suggests those continents were once connected and have since drifted apart.
Q3: What is seafloor spreading?
Answer: New oceanic crust forms at mid-ocean ridges as magma rises, pushes apart, and cools, gradually moving the ocean floor outward.
People Also Ask
What is Plate Tectonics and Evidence in Grade 8 Science?+
Plate Tectonics and Evidence is a lesson in the Earth and Space chapter of Grade 8 Science. It is part of the Alaska, USA school curriculum and covers key concepts that students need to understand at this level.
What grade level covers Plate Tectonics and Evidence?+
Plate Tectonics and Evidence is taught in Grade 8 as part of the Science curriculum in Alaska, USA.
How can I help my child with Earth and Space in Science?+
Start with the lesson summary and explanation on this page. Practice the questions provided, then use TutorTom for personalized, step-by-step help with Earth and Space topics.