Guided Exploration: How Earth Formed

1. Meteorites (#1–3)

The most important clues to the composition of the early solar system come from meteorites. Observe these three and explore the evidence about Earth’s formation that they contain.

2. Four Density Blocks (#4-7)

When Earth was forming, heavier materials like iron sank to the center to form the core and lighter ones like silicates rose to the surface. Lift the four samples and compare their weights. How does this connect to how Earth’s layers are organized?

3. Banded Iron (#23, 15) and Stromatolite (#14)

Rocks can contain important clues about the atmosphere. In early Earth, metals like iron were released into the ocean from hot springs but remained in solution in the water. When photosynthetic organisms began producing oxygen, it reacted with the iron in the seawater and precipitated as iron oxide to form the banded iron formation. Eventually, oxygen began to accumulate in the atmosphere. Observe both banded iron formations and the stromatolite (the fossilized remains of early oxygen-producing microbes). Then, look at the “How Do We Know About the Early Atmosphere?” diagram to explore the way these two rocks formed and what this tells us about the early atmosphere.

4. Sulfide Chimneys and Banded Ore (#26)

Chimneys form today when iron and other metals from underwater hot springs react with seawater and precipitate, in this case as sulfide minerals. Walk past the Dynamic Earth Sphere to observe the chimneys at the other end of the hall. Examine the “Deep-Sea Vents and Ore Deposits” panel to find out how these two very different ore deposits formed.