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Earth Systems Science · Module 1 · Station Lab

The Bonding Bench

HS-PS1-1 HS-PS1-3 4 stations ~45 minutes

Table salt shatters along flat faces while quartz breaks like glass — same planet, same atoms, different bonds.

Phase 0 · The phenomenon

Two crystals, two ways to break

Broken halite (left) splits along three sets of flat planes at right angles. Broken quartz (right) shows curved conchoidal fracture surfaces.

Left: a block of halite drawn as stacked cubes with flat faces meeting at right angles and step-like edges. Right: a quartz fragment with curved, nested shell-shaped ridges on its broken surface and sharp curved edges.

Tap a crystal of halite — rock salt — with a hammer and it splits into smaller and smaller cubes, every face flat and every corner square. Tap a quartz crystal just as hard and it breaks like a bottle: curved, shell-shaped surfaces with sharp edges and no flat faces at all.

Both minerals are made of ordinary elements from the first rows of the periodic table. Both are hard enough to be gemstones or road salt. So why do they fail in such different ways?

The answer is hidden two levels down — in how many electrons the atoms carry, and in how those atoms hold on to each other.

Essential question

Why do halite and quartz — both made of common elements — break in such different ways, and what does the way a mineral breaks tell you about the forces between its atoms?

What this lab works toward

  • HS-PS1-1Use the periodic table to predict how elements behave from the pattern of electrons in their outermost level.
  • HS-PS1-3Investigate bulk properties of substances to infer how strong the electrical forces between their particles are.

Plain-English summaries. The course maps these performance expectations to this lab; the official wording is published at nextgenscience.org.

The stations

  1. Outer ElectronsHow does an element's outer-electron count predict how it bonds?
  2. Bond MeterIs the silicon–oxygen bond in quartz more like salt's bond or more like a shared bond?
  3. Break TestWhy does a crack in halite follow flat planes while a crack in quartz wanders?
  4. Mass CheckWhen calcite fizzes away in acid, where does the mass go?

Each station runs the same loop: predict before you see any data, investigate the model and record runs, reveal what the measurements show, then explain the gap between your prediction and the result. A claim-evidence-reasoning checkpoint and an exit ticket close the lab.