Earth's Layers and Density
Earth's Layers and Density
Big Idea:
When Earth was young and melted, denser materials sank to the center, and lighter materials floated to the top—just like in this experiment!

What You’ll Need:
  • A clear glass or jar
  • Water
  • Corn syrup or honey
  • Vegetable oil
  • A spoon or dropper
  • Optional: small solid items of different densities (like a pebble, a grape, a plastic bead, a cork)
Steps:
  1. Pour in the heaviest liquid first (corn syrup or honey) — this is your inner core.
  2. Slowly pour water on top — this is your mantle.
  3. Gently add vegetable oil — this is your crust.
  4. Watch the liquids form layers!
  5. Optional: Drop in small solid objects. Which ones sink? Which float? Which stay in the middle?
Level 1 Explanation:
When Earth was very hot and melted, the heavy stuff (like metal) sank to the bottom, and the lighter stuff floated on top. That’s how Earth got layers!

Level 2 Explanation:
When Earth first formed, it was extremely hot—so hot that the whole planet was mostly melted.
Because of that, materials inside Earth were able to move and separate based on their density:
  • Denser materials (like iron and nickel) sank toward the center.
  • Lighter materials (like silicates) floated toward the top.
This process is called planetary differentiation (they don't need to know this term!) and it’s why Earth has layers today:
  • Core (the densest layer)
  • Mantle
  • Crust (the least dense layer)
In our experiment:
  • Honey or corn syrup represents the core—it's the heaviest and sinks to the bottom.
  • Water represents the mantle—it's lighter than syrup but heavier than oil.
  • Oil represents the crust—it floats on top because it's the least dense.
When we add small objects (like pebbles or beads), we can see that where they settle depends on their density, just like how real materials moved inside the early Earth.