This lesson focuses on the element silicon, its presence in pigments, and its detection through XRF spectroscopy. Silicon is a key component of many earth pigments due to its abundance in silicates, a group of minerals widely used in art. By examining various materials, including pure silicon, glass, and pigments like ultramarine derived from lapis lazuli, students will explore how silicon can be identified in these substances.
Objectives
- Understand the role of silicon in pigments and other materials.
- Analyze and compare XRF spectra of pure silicon, silicate-based materials, and pigments to identify silicon and other elements.
Materials
- Samples:
- Pure silicon
- Glass (e.g., microscopy slide)
- Lapis lazuli stone
- Natural ultramarine pigment from Pigments Checker standard version
- XRF spectrometer, no-filter setup
Lesson Plan
- Experiment 1: Pure Silicon Analysis
- Analyze a sample of pure silicon using the XRF spectrometer.
- Observe and discuss the strong peak at 1.7 keV in the spectrum.
- Experiment 2: Glass Analysis
- Examine a microscopy slide.
- Compare its XRF spectrum to that of pure silicon, noting the lower intensity of the silicon peak and the additional peaks, including calcium, which is commonly added to glass.
- Experiment 3: Lapis Lazuli Stone
- Analyze a piece of lapis lazuli stone and observe its XRF spectrum.
- Experiment 4: Ultramarine Pigment Analysis
- Test a natural ultramarine pigment derived from crushed lapis lazuli.
