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Earth Systems Science · Module 1 · Station Lab

The Mineral ID Bench

HS-PS1-3 HS-ESS3-2 4 stations ~50 minutes

Two samples look identical in the hand, but one leaves a red streak and sinks the balance — the lattice is telling on itself.

Phase 0 · The phenomenon

Twins that are not twins

Two look-alike samples: equal sizes on a balance that tips toward one of them, and the streaks they leave on a porcelain plate.

A two-pan balance holding two grey metallic samples of the same size; the left pan sits lower. Below, a white streak plate shows a reddish-brown streak from the left sample and a dark grey streak from the right sample.

Two steel-grey, metallic-looking samples sit on the bench, the same size and the same shine. A visitor swears they are the same mineral.

Rub each across a white porcelain plate: one leaves a black-grey line, the other a reddish-brown one. Put them on a balance: the red-streak sample is more than twice as heavy.

Colour and shine fooled the eye. In this lab you will use the tests geologists trust — streak, density and hardness — and find out why those tests read the crystal lattice itself. Then you will put the right mineral to work as an ore.

Essential question

If two minerals look the same in your hand, which tests tell them apart — and why do those tests reveal what is going on inside the crystal?

What this lab works toward

  • HS-PS1-3Investigate bulk properties of substances to infer how strong the electrical forces between their particles are.
  • HS-ESS3-2Weigh competing ways to develop and use energy and mineral resources by comparing their costs and benefits.

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

The stations

  1. Streak PlateWhy is streak a more reliable clue than the colour of the sample?
  2. Density CylinderHow do mass and displaced water reveal a mineral's density?
  3. Scratch TestWhat does the Mohs scratch test really measure?
  4. Ore GradeHow do mineral chemistry and ore grade decide how much iron a tonne of rock yields?

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.