Learning targets

1. Students can describe how heat treatment of materials alone can change

a material’s properties.

2. Students can shape Styrofoam balls into various crystal forms.

Sulfur

Monoclinic(from a melt)

Orthorhombic(from solution)

Amorphous Sulfur

Allotropes of Sulfur

rhombic amorphous monoclinic

Why are Crystals Important?

Discuss the following question at your tables and be prepared to share your answer.

Have you ever had a experience where a material could change its behavior with different types of heat treatment?

Bedazzled!!!!!

• http://www.thatcrystalsite.com/downloads/NaicaCrystalCave.pps#257,1,Slide1 – Giant crystals in cave in Mexico

Models of Crystals Lab

• Look for spacing (tightly vs. loosely packed – “gappiness”)

• Look for relative number of slip planes

• Try combining several examples of the same model into a bigger one

Simple cubic

Face-centered cubic(FCC)

Body-centered cubic(BCC)

Hexagonal close packed(HCP)

Most Common Metal Crystal

Structures

• BCC Body Centered Cubic

• FCC Face Centered Cubic

• HCP Hexagonal

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