Volcanic Activity (Deep Dive)
📋 What it is
Volcanoes vary from gentle lava flows to explosive eruptions, depending on the magma’s thickness and gas.
🗣️ Coach says
Not all volcanoes erupt the same way. Runny, low-gas magma oozes out as gentle lava flows (like Hawaii); thick, gas-rich magma traps pressure and erupts explosively (like Mount St. Helens). The magma’s stickiness and gas content decide whether it flows or blows.
🧠 Memory hook
Runny low-gas magma = gentle flows · thick gassy magma = explosive blast. Stickiness + gas decide.
😂 Giggle
Why was the sedimentary rock so cheap?
Because it was made from deposits!
😲 Whoa!
The 1883 eruption of Krakatoa was so loud it was heard nearly 5,000 km away — one of the loudest sounds in recorded history.
✅ Quick check: Why do some volcanoes ooze gentle lava while others explode?
Say your answer out loud first — then reveal.
Runny, low-gas magma flows out gently; thick, gas-rich magma traps pressure and erupts explosively.
Magma viscosity and gas content control eruption style.
🧪 Try it! (2 minutes)
Compare honey (thick, traps bubbles) vs water (runny) — thick magma traps gas and blows.