---
title: "Soil Colour as Physics — Earth Pigments from the Soils of Müllrose"
subtitle: "A Concept for Physics Education — From Soil Sample to Artwork"
author: "Michel Garand"
date: "February 2026"
version: "1.1"
lang: en
license: "CC BY-NC-SA 4.0"
project: "Erdpuls OER Collection"
---
# Soil Colour as Physics — Earth Pigments from the Soils of Müllrose

## A Concept for Physics Education within "Brücken bauen durch Boden — 13 Questions to the Soil"

**Erdpuls — Living Laboratory \& Makerspace Garden**

**Version**: 1.1
**Date**: February 2026

* * *

## Changelog

| Version | Date          | Changes                                                                                                                                                                          |
|---------|---------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 1.1     | February 2026 | BNE compliance update: YAML front matter added; section dividers converted to `* * *`; Pedagogical Framework \& BNE Orientation section added (4A-Pathway, BNE quality areas table, SDGs, Gestaltungskompetenzen); overview table added; BNE Quality Framework Alignment section added before Further Resources; colophon standardised to Erdpuls format. |
| 1.0     | January 2026  | Initial release.                                                                                                                                                                 |

* * *

| | |
|---|---|
| **Title** | Soil Colour as Physics — Earth Pigments from the Soils of Müllrose |
| **Target Group** | Secondary school students (Grades 5–12); differentiated by grade band |
| **Duration** | 8–12 lessons across four phases (fieldwork, lab, measurement, production) |
| **Location** | Zone B (Bio-Materialien-Gartenlabor) \& field sites; partner farms |
| **Season** | February–June (main sequence); September (deepening experiment) |
| **4A-Pathway Focus** | All four stages: Awareness (field) -> Acknowledgment (lab) -> Attitude (correlation) -> Action (pigment production for WP4) |

* * *

> *"Colour is the smile of nature."* — Leigh Hunt
>
> *"Soil is not brown. It is a thousand colours."* — Michel Garand

* * *

## Pedagogical Framework and BNE Orientation

This document is part of the Erdpuls OER Collection and is designed to support full compliance with the *Qualitätskatalog für außerschulische Anbieterinnen und Anbieter von Bildung für nachhaltige Entwicklung (BNE) im Land Brandenburg* (MLUK Brandenburg, April 2023). It is a physics education concept document for school groups working within the "Brücken bauen durch Boden" project strand. It directly addresses Angebotsqualität criteria for which scientific inquiry, experiential fieldwork, and art–science integration are the relevant evidence.

### BNE Quality Areas Addressed

| Area | Title | Status |
|---|---|---|
| 1 | Goals and Target Groups | All criteria met — three explicitly differentiated grade bands (5–8, 9–10, 11–12) with distinct learning objectives, methods, and cognitive demands; project connection to partner farms grounds the content in students' regional Lebenswelt (1.1.1) |
| 2 | Approach | All criteria met — ecological (soil mineralogy), economic (farming method), social (farmer dialogue), and cultural (art tradition of earth pigments) dimensions are linked (2.1.1); SDG 4, 13, 15, and 2 addressed; controversial thesis (inner attitude -> soil quality) opens genuine perspective plurality (2.2.1) |
| 3 | Methods | Minimum requirements met — action-oriented (pigment production), experiential (fieldwork, wet grinding), reflective (wet–dry diagrams, spectroscopy), and participatory (partner farm soil samples); theoretical grounding (ligand field theory, Mie scattering, colloid physics) fully meets 3.2; teacher preparation resources in Section 9 meet 3.3 |
| 4 | Gestaltungskompetenz | Key sub-competencies addressed — 4.1.1 (world-open, new perspectives: three farming systems; mineralogy across cultures); 4.1.2 (forward-looking analysis: senior thesis scenarios); 4.1.3 (interdisciplinary: physics/chemistry/art/biology); 4.1.4 (risk recognition: silicosis safety protocol); 4.3.1 (values reflection: farming attitude -> soil -> colour); 4.2.1 (collaborative planning: correlation study design) |
| 5 | Quality Development | Minimum requirements met — experimental data (spectra, Δ*E* values, grain size distributions) constitute longitudinal evaluation evidence; seasonal deepening experiment (September) supports 5.2.1 continuous reflection |
| 6 | Facilitator Qualification | Minimum requirements met — Section 9 (Further Resources) provides structured teacher preparation materials; differentiation-by-grade-level tables serve as facilitator preparation tools (6.2.1) |
| 7 | Organisational Conditions | Addressed at programme level; equipment in Zone B (Boden-Labor) and Zone C (sensor dashboard) supports 7.4 (infrastructure) |

The complete criterion-by-criterion mapping for criteria directly addressed by this document is in the *BNE Quality Framework Alignment* section at the end of this document. For the full programme-level alignment across all 57 criteria, see the *BNE-Qualitätsbewertung und Leitbild* (February 2026).

### The 4A-Pathway in This Document

Every educational sequence at Erdpuls follows the 4A-Pathway. In the soil pigment concept, the pathway maps onto the four experimental phases:

| Stage | Soil Pigment Activity |
|---|---|
| **Awareness** | Phase 1 — Fieldwork: body moving through three farm landscapes at intimate and personal proxemic distance, accumulating direct sensory evidence. Students notice colour differences in soil between farms before any explanation is offered. "Why is this soil red and that one grey?" |
| **Acknowledgment** | Phase 2–3 — Laboratory processing and spectroscopy: recognising that the sensory difference felt in the field is physically measurable (grain size, reflection spectrum, CIELAB Δ*E*) and chemically explainable (iron oxide mineralogy, organic carbon). Measurement confirms and deepens what the hands already knew. |
| **Attitude** | Section 6 — Correlation study: forming the view that a farmer's inner attitude toward the soil is legible in its mineralogy, its colour, and ultimately in the painting made from it. This is not a given — it is a hypothesis students investigate. The science does not close the question; it opens it further. |
| **Action** | Phase 4 — Producing the Müllrose Earth Colour Library: scientific findings become the material for the 104 WP4 exhibition paintings. Students are not producing samples — they are producing the actual medium for an artwork that will travel. |

### Three-Stream Pedagogy

This concept addresses all three streams of the Erdpuls Three-Stream Pedagogy simultaneously:

- **Head** — Physics and chemistry of colour: absorption spectra, Mie scattering, ligand field theory, colloid physics, CIELAB colour space
- **Hands** — Wet and dry grinding, sieve analysis, pigment preparation, binder comparison, spectrometer operation
- **Heart** — The soil as witness to a farmer's relationship with the land; the pigment as the soil's voice in the exhibition; colour as encounter between human perception and matter

### SDG Alignment

| SDG | Integration |
|---|---|
| SDG 4 Quality Education | Core purpose — interdisciplinary physics education grounded in place-based inquiry and authentic scientific practice |
| SDG 13 Climate Action | senseBox moisture and temperature data correlated with pigment colour variation (Section 5, Grade 11–12 track); soils as climate archive |
| SDG 15 Life on Land | Soil as living system; iron oxide mineralogy as indicator of soil health and management history; Naturpark Schlaubetal as reference landscape |
| SDG 2 Zero Hunger | Three farming systems (conventional/organic/biodynamic) compared through soil quality indicators including colour — connecting farming practice to soil vitality |

* * *

## 1. Introduction and Project Context

### 1.1 Why Physics and Soil Colour?

The production of earth pigments is not a peripheral craft activity — it is a window into the physics of matter. Why does an iron-rich soil from Müllrose glow red-orange? Why does wet soil appear darker than dry soil? Why does a more finely ground pigment cover better than a coarsely ground one? These questions lead directly into core areas of physics: optics, light-matter interaction, colloid physics, and particle size analysis.

In the project "Brücken bauen durch Boden — 13 Questions to the Soil", **104 answers are painted in earth colours** — each farmer's answer to each of the 13 questions. These paintings are created in the soil painting laboratory (WP4). This concept connects that artistic centrepiece with science education: students understand physically what they experience artistically.

### 1.2 Connection to Project Objectives

The pigment experiment connects three project dimensions simultaneously:

- **Science:** Analysing soil samples, measuring pigment properties, evaluating data
- **Art:** Producing earth pigments, applying them in the exhibition artworks
- **Dialogue:** Each of the three partner farms supplies soil samples with different colours — the soils "speak" with different voices

* * *

## 2. Geological and Pedological Background — The Soils of Müllrose

### 2.1 The Soils of the Oder-Spree Region

Müllrose lies in the Naturpark Schlaubetal in the Oder-Spree region of Brandenburg. The soils are predominantly Pleistocene glacial deposits from the last ice ages. The following soil types are particularly interesting for pigment production:

| Soil type | Characteristics | Colour | Where to find it |
|---|---|---|---|
| **Podzol** | Iron-depleted upper layer, iron-enriched hardpan (ortstein) | Grey-white to rust-brown | Pine forests around Müllrose |
| **Brown earth (Cambisol)** | Iron oxide-rich weathering soils | Yellow-brown to reddish | Agricultural fields, slopes |
| **Fen/Bog soil** | Rich in organic matter, peaty | Dark brown to black | Lake shores, wet meadows |
| **Gley soil** | Rust patches from iron redox cycling | Orange-rust with grey zones | Near-shore areas |
| **Anmoor (semi-organic)** | Semi-organic transitional | Dark grey to black | Fen/mineral soil transitions |
| **Sandy raw soil** | Quartz-rich | White to pale yellow | Sandpits, brownfield sites |

### 2.2 The Key Colour-Forming Minerals in Müllrose Soils

**Iron (Fe) — the dominant colour source of the region**

Iron is the most common colour-forming element in Brandenburg soils. Its compounds produce the complete spectrum from yellow through orange to dark red:

- **Goethite (α-FeOOH):** The most common iron mineral in soils -> Yellow to yellow-brown
- **Lepidocrocite (γ-FeOOH):** Forms under redox cycling -> Orange-red
- **Haematite (α-Fe₂O₃):** Produced under warm weathering -> Red-brown to red
- **Ferrihydrite (Fe₅O₈H·4H₂O):** Freshly precipitated, poorly crystalline -> Red-orange

**Organic matter — the dark witness of life**

Humic and fulvic acids give soils their dark colours. The more organic matter, the darker the soil. The fen soils around the Müllroser See can yield deep blacks and umber tones.

**Manganese (Mn) — rare but deep**

Manganese oxides form black spots and concretions in gley soils. They can provide intense blacks and dark browns.

**Quartz (SiO₂) — the bright base tone**

The sandy soils of the region consist predominantly of quartz — it contributes the whites and pale greys.

### 2.3 Sample Collection Map — Recommended Sites

| Site | Soil type | Expected colour | Approximate location |
|---|---|---|---|
| Forest edge east of Müllrose | Podzol ortstein | Rust-brown | Schermützelsee area |
| Agrargenossenschaft Müllrose | Brown earth | Yellow-brown | Partner farm field |
| Müllroser See lakeshore | Gley soil | Orange-rust | Shore sediment |
| Wet meadow to the west | Fen soil | Dark brown | Fen margin |
| Sandpit / brownfield | Raw soil | White–pale grey | Open sandy areas |
| Komturei Lietzen | Loamy brown earth | Warm brown | Partner farm |
| Hof Marienhöhe | Biodynamically managed | Dark, humus-rich | Partner farm |

* * *

## 3. Physical Principles — Why Soils Have Colour

### 3.1 Light-Matter Interaction

Colour arises through **selective absorption** of portions of light. White light (sunlight) contains all wavelengths of the visible spectrum (approximately 380–780 nm). A pigment absorbs certain wavelengths and reflects others — the reflected portions are what we perceive as colour.

**Why is goethite yellow?**
Goethite preferentially absorbs violet and blue light (380–480 nm) through ligand-field transitions of the Fe³⁺ ion. The remaining reflected light appears yellow-orange.

**Why is haematite red?**
Haematite has a different crystal structure. The Fe³⁺ ions are differently coordinated, shifting the absorption band toward the blue-green region -> the remaining reflected light appears red.

**Why does wet soil appear darker?**
Water fills the air pores in the soil. Dry soil scatters light through countless air-mineral interfaces (Mie scattering) -> strongly brightened. Wet soil has fewer interfaces -> less scattering -> darker. This phenomenon can be measured quantitatively in class.

### 3.2 Pigments vs. Dyes — a Fundamental Physical Distinction

| Property | Pigment (insoluble) | Dye (soluble) |
|---|---|---|
| **Solubility** | Insoluble in the binder | Soluble in water or solvent |
| **Colour mechanism** | Scattering and absorption | Absorption only |
| **Covering power** | High (particles scatter light) | Low (transparent) |
| **Light fastness** | Usually very high | Often lower |
| **Earth colours** | Always pigments | — |

**Classroom prompt:** Earth colours are pigments. They cover because their particles scatter light (Mie scattering). The smaller the particles, the finer the colour — but below a certain particle size, the colour itself changes (quantum effects in nanoparticles).

### 3.3 Particle Size and Colour Intensity

A central physical principle of pigment production:

**Grinding changes the colour!**

- **Coarse particles (> 50 μm):** Grainy texture, paler colour due to strong diffuse scattering
- **Medium particles (5–50 μm):** Optimal covering power, rich colour
- **Fine particles (< 5 μm):** Very intense colour, but weak covering power, may become semi-transparent

**Measurement experiment:** Students grind the same soil sample to different fineness, prepare a pigment from each fraction, and compare the reflection curves using a spectrometer or spectroscopy app (e.g. Spectroid).

### 3.4 Binders and Colloid Physics

The binder determines how pigment particles are held within the paint film. Physically, this concerns **colloidal suspension** and **film formation**:

| Binder | Physical mechanism | Result |
|---|---|---|
| **Linseed oil** | Oxidative polymerisation (drying through O₂ uptake) | Elastic, long-lasting film |
| **Gum arabic** | Polysaccharide solution, dries through water evaporation | Brittle, water-soluble film |
| **Egg yolk (tempera)** | Oil-water emulsion, protein coagulation | Fast-drying, matte surface |
| **Casein (from quark)** | Protein polymer, insoluble after drying | Very strong, weather-resistant film |
| **Water (fresco technique)** | No binder — pigment embedded in lime plaster | Permanent but brittle |

**Experiment:** Same earth colour with five different binders -> compare covering power, drying time, crack formation, colour shift on drying (all colours lighten as they dry — why?).

* * *

## 4. Experimental Sequence — From Soil to Painting

### Phase 1 — Soil Sampling and Documentation (Fieldwork, 2 lessons)

**Learning objectives:**

- Collect soil samples systematically and document them
- Assess colour using the Munsell Soil Color System (or a simplified version)
- Record site parameters (vegetation, moisture, depth)

**Materials:**

- Sample bags (200–500 g per site)
- Munsell Soil Color Chart (or photographic colour reference as an aid)
- Site description form
- pH indicator strips (field estimate)

**Procedure:**

1. Expose a soil profile (spade, 30 cm deep) — sample at three depths: 0–5 cm, 10–15 cm, 25–30 cm
2. Record soil colour wet and dry
3. Estimate soil texture in the field (sand/silt/clay by finger test)
4. Photographs with scale bar and location marker
5. Record GPS coordinates for the project map

**Project connection:** Samples from the three partner farms (conventional, organic, biodynamic) are directly compared — first visible differences are discussed in the field.

* * *

### Phase 2 — Laboratory Processing (2–3 lessons)

**Learning objectives:**

- Distinguish between wet and dry processing methods
- Understand the influence of grain size on pigment properties
- Follow safety rules when working with dusts

**Materials:**

- Oven or food dehydrator (50°C maximum — heat changes iron oxides!)
- Mortar and pestle (porcelain)
- Sieves: 500 μm, 250 μm, 100 μm, 63 μm
- Dishes, balance (1 mg resolution)
- Filter paper, funnel, beaker
- Safety goggles, FFP2 dust mask during grinding and sieving

**Processing steps:**

**Dry route (for most soils):**

1. Dry soil at 50°C (24 h) — why not higher? -> Goethite converts to haematite above approximately 250°C (becomes more reddish!)
2. Remove largest particles (stones, roots) by hand
3. Grind in the mortar — 5 minutes initially, then sieve analysis
4. Keep sieve fractions separately and compare
5. Weigh each fraction -> grain size distribution as histogram

**Wet route (for clay-rich samples):**

1. Stir soil into water, leave to settle (sedimentation)
2. Coarse fraction settles first (sand: < 1 min), fine fraction stays in suspension longer (silt: hours, clay: days)
3. Pour off fine suspension and dry on glass plates or film
4. Lift off the thin, colour-intensive clay pigment layer

**Safety note for the teacher:**

> Quartz-containing fine dust (< 10 μm) is hazardous to health with regular exposure (silicosis). In a school context the risk from occasional grinding is very low, but FFP2 respiratory protection and good ventilation are mandatory during grinding and sieving.

* * *

### Phase 3 — Pigment Characterisation — Physical Measurements (2–3 lessons)

**Experiment 3.1 — Reflection Spectroscopy**

*Goal:* Measure colour objectively and determine the absorption spectrum

*Methods (depending on available equipment):*

**Option A — Smartphone spectrometer (low cost):**

- App: "Spectroid" or "Physics Toolbox Sensor Suite"
- DIY spectrometer from a DVD diffraction grating and cardboard (instructions: Public Lab)
- Apply pigment paste to white paper, record reflection spectrum
- Read off the wavelength of the absorption maximum

**Option B — School spectrometer:**

- Spread thin pigment paste on glass plate
- Reflection measurement at known wavelengths (Fraunhofer lines as reference)

**Option C — Digital colour analysis:**

- Photograph pigment sample with calibrated camera
- Read RGB values (GIMP or similar software)
- Convert to CIELAB colour space (more precise colour description)
- Compare colours quantitatively as Δ*E* value

**Experiment 3.2 — Grinding Time vs. Colour Intensity**

*Goal:* Measure the relationship between particle size and colour saturation

| Grinding time | Particle size (sieve analysis) | Colour saturation (measured) | Covering power (visual) |
|---|---|---|---|
| 0 min (raw) | > 500 μm | low | coarse |
| 5 min | 100–500 μm | medium | medium |
| 15 min | 63–100 μm | high | good |
| 30 min | < 63 μm | very high | very good |

Students plot the measurements and describe the relationship mathematically (linear? saturation curve?).

**Experiment 3.3 — Wet–Dry Effect**

*Goal:* Understand the physical mechanism of colour lightening as paint dries

1. Apply earth colour to paper wet, photographic record every 5 minutes
2. Measure RGB value and plot in a diagram (brightness vs. time)
3. Work out the explanation: what role does Mie scattering at air-pigment interfaces play?

**Experiment 3.4 — Binder Comparison**

*Goal:* Compare the physical properties of different binders

For each earth colour × 5 binders = test patch on card:

- Colour shift on drying (measure Δ*E*)
- Drying time (in minutes)
- Crack formation (yes/no, crack width in mm)
- Water resistance (droplet test after 24 h drying)
- Adhesion (tape peel test after 48 h)

* * *

### Phase 4 — Pigment Production for WP4 (1–2 lessons)

**From laboratory sample to artist's pigment**

Once the optimal grinding time and preferred binder have been identified, students produce sufficient pigment for the artworks.

**Standard recipe — Egg tempera (anthroposophic tradition):**

```text
Earth pigment:    2–3 parts (adjusted by absorbency)
Egg yolk:         1 part
Water:            0.5–1 part (depending on desired consistency)
Preservation:     1 drop of clove oil or thyme oil (mould inhibitor)
```

**Standard recipe — Watercolour/gouache:**

```text
Earth pigment:    3 parts
Gum arabic:       1 part (10% solution in distilled water)
Glycerine:        0.2 parts (prevents cracking)
Honey:            0.1 parts (moisture regulator)
```

**Standard recipe — Oil paint:**

```text
Earth pigment:    4–5 parts
Raw linseed oil:  1–1.5 parts
Drying agent:     0.05 parts (accelerates drying, optional)
```

All pigments are stored in labelled jars — they form the **Müllrose Earth Colour Library** of the project.

* * *

## 5. Differentiation by Grade Level

### Grades 5–8 — Discovery-based and Experimental

**Focus:** Phenomenology and experience-based learning

- Collect soil samples and "sort them by colour" without explanation -> spark curiosity
- Wet grinding by hand (clay samples) — tactile access
- Simple binder comparison: water vs. linseed oil vs. egg yolk
- Paint with the students' own pigments -> direct connection to WP4
- Question: "Why does soil become lighter when it dries?" as an entry point into optics

**Cross-curricular connections:** Biology (soil organisms), Art (colour theory), Geography (regional geology)

### Grades 9–10 — Causal Understanding

**Focus:** Quantitative relationships and model building

- Reflection spectroscopy with smartphone app
- Sieve analysis with grain size distribution
- Wet-dry diagram (introduce physical explanation of Mie scattering)
- Binder comparison with measurable parameters
- Short presentation: "Why are iron oxides coloured?" (introducing ligand field theory as a model)

**Cross-curricular connections:** Chemistry (oxides, crystal structures), Mathematics (statistics, graphs)

### Grades 11–12 — Research-based and Critical

**Focus:** Independent research and scientific communication

- Independent experimental design: "Which soil parameter correlates most strongly with pigment colour intensity?"
- Quantitative spectroscopy, CIELAB colour space, Δ*E* value
- Comparison of pigment spectra with reference minerals (RRUFF database online)
- Correlation between sensor data (senseBox moisture readings) and pigment colour (colour lightening)
- Possible senior thesis: "The influence of farming method on iron oxide mineralogy and thus on the pigment colour of Müllrose soils"

* * *

## 6. Connection to the Project Correlation Study

This teaching module contributes directly to the project's central scientific thesis:

**Thesis:** *A farmer's inner attitude toward the soil is reflected in measurable soil quality.*

Pigment colour is an **additional objective measurement parameter**: soils from differently managed farms differ not only in pH, moisture, and humus content — they differ visibly in their colour. These colour differences are physically measurable (Δ*E* in CIELAB space) and chemically explicable (iron oxide mineralogy, organic carbon content).

**Possible research question for upper school:**
Is there a correlation between the reflection spectrum of a soil sample and its humus content, iron oxide type, or management regime?

This question can be combined with the sensor data from the senseBox: does the spectrum of the surface sample vary seasonally depending on moisture and temperature (which the senseBox measures)?

* * *

## 7. Materials List and Costs

### Basic Equipment (one-time investment)

| Item | Quantity | Approx. cost |
|---|---|---|
| Porcelain mortar and pestle set (large + small) | 2 | €35 |
| Sieve set (500/250/100/63 μm) | 1 set | €45 |
| Digital laboratory balance (1 mg) | 1 | €40 |
| Laboratory bottles/screw-top jars (50 ml) | 30 | €15 |
| FFP2 dust masks | 30 | €20 |
| Safety goggles | 15 | €20 |
| Munsell Soil Color Chart (simplified) | 1 | €30 |
| **Basic equipment total** | | **approx. €205** |

### Consumables (per school year)

| Item | Approx. cost |
|---|---|
| Cold-pressed linseed oil (500 ml) | €8 |
| Gum arabic (200 g) | €12 |
| Glycerine (250 ml) | €5 |
| Watercolour paper 300 g/m² (50 sheets) | €15 |
| Filter paper, dishes, disposable gloves | €10 |
| **Consumables total** | **approx. €50/year** |

### Digital Tools (free)

- **Spectroid** (iOS/Android): spectrometer app
- **GIMP:** Image editing and colour analysis
- **RRUFF Project** ([rruff.info](https://rruff.info)): Reference spectra for minerals
- **SoilGrids** ([soilgrids.org](https://soilgrids.org)): Online soil maps for comparison

* * *

## 8. Timeline and Integration into the 2026 School Year

| Period | Activity | Connection to project plan |
|---|---|---|
| **February–March** | Sampling at all four sites (school garden + 3 farms) | Parallel to sensor installation (WP2) |
| **March–April** | Lab phase 1: drying, grinding, sieving | Preparation of soil painting laboratory (WP4) |
| **April–May** | Lab phase 2: spectroscopy, binder comparison | Parallel sensor data collection starts |
| **May–June** | Pigment production for WP4 | Dialogue SOWING — first paintings created |
| **September** | Deepening experiment: correlation sensor data and pigment | Dialogue DROUGHT — harvesting data |
| **October–November** | Evaluation, results presentation | Preparation of exhibition "104 Answers" |
| **December** | Presentation on World Soil Day | Closing symposium |

* * *

## 9. BNE Quality Framework Alignment

*This section provides criterion-by-criterion mapping for criteria directly addressed by this document. For the full programme-level alignment across all 57 criteria, see the Erdpuls BNE-Qualitätsbewertung und Leitbild (February 2026).*

### Area 1 — Goals and Target Groups

| Criterion | Status | Evidence in this document |
|---|---|---|
| 1.1.1 Lebenswelt- und Lebensphasenbezug | Met | Content grounded in Müllrose soils, partner farms, and Naturpark Schlaubetal — the direct living environment of participating students. Soil samples come from sites students can visit. |
| 1.2.1 ZG sind konkret beschrieben | Met | Three grade bands (5–8, 9–10, 11–12) with distinct learning objectives, cognitive demands, and cross-curricular connections. Section 5. |
| 1.2.2 Bedarf ist ZG-spezifisch beschrieben | Met | Each grade band addresses a different developmental need: phenomenological experience (5–8), causal modelling (9–10), independent research (11–12). |
| 1.2.3 Ziele sind konkret und ZG-spezifisch | Met | Learning objectives stated per phase and per grade band throughout Sections 4 and 5. |
| 1.2.4 Bedarf, Ziele und Zielgruppe passen zusammen | Met | The progression from sensation -> measurement -> correlation -> production maps coherently onto age-appropriate cognitive development. Red thread is visible. |

### Area 2 — Approach

| Criterion | Status | Evidence in this document |
|---|---|---|
| 2.1.1 Multidimensional | Met | Ecological (iron oxide mineralogy), economic (farming method and soil health), social (farmer dialogue, three farm systems), and cultural (earth pigment tradition, WP4 exhibition) dimensions are explicitly connected. |
| 2.1.2 Inter-/transdisziplinär | Met | Physics, chemistry, geology, art history, ecology, and farming practice are integrated throughout. Grade 11–12 track explicitly frames the correlation study as transdisciplinary research. |
| 2.1.3 Aktuell-relevant | Met | SDG 4, 13, 15, 2 explicitly addressed. Soils as climate archive and farming method comparison are directly current sustainability issues. |
| 2.2.1 Kontrovers | Met | The central project thesis — that a farmer's inner attitude is measurable in soil colour — is explicitly framed as a hypothesis, not a given. Perspective plurality is built into the three-farm comparison. |
| 2.2.2 Global-lokal | Met | Local: Müllrose soils, Schlaubetal region. Global: CIELAB international colour standard, RRUFF mineral reference database, SoilGrids global comparison. Iron oxide mineralogy as a globally shared phenomenon addressed through local soils. |

### Area 3 — Methods

| Criterion | Status | Evidence in this document |
|---|---|---|
| 3.1.1 Handlungsorientiert | Met | Students physically collect, grind, measure, and produce pigments. Phase 4 produces real materials for a real artwork. |
| 3.1.2 Erfahrungsorientiert | Met | Fieldwork phase grounds all subsequent learning in direct sensory encounter with soil. "Body first, then instrument" principle explicit. |
| 3.1.3 Entdeckend | Met | Sorting samples by colour "without explanation" (Grades 5–8) explicitly uses discovery-based methodology. Open-ended research question for Grades 11–12. |
| 3.1.4 Kooperativ | Met | Partner farm sampling is inherently cooperative. Correlation study is designed as group research. |
| 3.1.5 Reflektiert | Met | Wet–dry diagram, grinding-time vs. colour experiments, and binder comparison all require students to explain their observations. Grade 11–12 reflection on methodology (which parameter correlates most?). |
| 3.1.6 Partizipativ | Partial | Farmer participation in sample supply is documented. Student co-design of the Grade 11–12 research question is encouraged but not procedurally specified. |
| 3.2 Theoretische Fundierung | Met | Section 3 provides full theoretical background (optics, Mie scattering, ligand field theory, colloid physics). Literature references in Section 9. |
| 3.3 Vorbereitung unterstützen | Met | Section 9 provides teacher literature, online resources, and a structured materials list. |

### Area 4 — Gestaltungskompetenz

| Sub-competency | Status | Evidence |
|---|---|---|
| 4.1.1 Weltoffen, neue Perspektiven | Met | Three farming systems compared. Iron oxide pigments as a shared global heritage (ochre, sienna, umber) introduced alongside local soils. |
| 4.1.2 Vorausschauend analysieren | Met | Senior thesis scenario: "What does iron oxide mineralogy tell us about future soil quality under different management regimes?" explicitly introduced in Grade 11–12 track. |
| 4.1.3 Interdisziplinär handeln | Met | Physics, chemistry, art, ecology, and agronomy integrated throughout. The pigment is both a scientific measurement result and an artistic material. |
| 4.1.4 Risiken erkennen | Met | Silicosis safety protocol (Phase 2) explicitly teaches risk recognition and precautionary behaviour under uncertainty. |
| 4.2.1 Gemeinsam planen | Met | Group sampling expeditions, shared correlation study design, collective production of the Earth Colour Library. |
| 4.3.1 Sich motivieren können | Met | Each student's pigment production contributes directly to the WP4 exhibition — a real public outcome. The work is not just a school exercise. |
| 4.3.3 Vorstellungen von Gerechtigkeit | Partial | Farming method comparison touches on questions of land stewardship and sustainable land use. Not explicitly framed as a justice question in this document. |

### Area 5 — Quality Development

| Criterion | Status | Evidence |
|---|---|---|
| 5.1 Qualitätsentwicklung | Met | Experimental data (spectra, Δ*E* values, grain size distributions) constitute measurable learning outcomes. Timeline (Section 8) enables iterative programme development across the school year. |
| 5.2.1 Kontinuierliche Praxisreflexion | Met | September deepening experiment explicitly revisits and correlates earlier measurements with new sensor data — built-in longitudinal reflection. |
| 5.2.2 Einbeziehung der Teilnehmenden | Partial | Grade 11–12 research question design involves participant input. Structured participant evaluation of the pigment production process not specified. |

### Area 6 — Facilitator Qualification

| Criterion | Status | Evidence |
|---|---|---|
| 6.1.1 Fachliche Qualifikation | Met (programme level) | Addressed in the Erdpuls BNE-Qualitätsbewertung. Section 9 provides the subject-matter resources teachers need to deliver this material confidently. |
| 6.2.1 Vorbereitung der Durchführenden | Met | Section 9 provides structured literature, online resources, and digital tool guidance. Grade-level differentiation tables serve as facilitator preparation scaffolding. |

### Area 7 — Organisational Conditions

| Criterion | Status | Evidence |
|---|---|---|
| 7.4.2 Lernorte | Met | Zone B (Boden-Labor) is specified as the primary location. Zone C (IoT workshop) for digital correlation. Field sites documented with GPS protocol. |

* * *

## 10. Further Resources for the Teacher

### Literature

- Kühn, H. (1984): *Pigments in Paintings of the Schack-Galerie Munich.* Doerner Institute.
- Schwertmann, U. \& Cornell, R.M. (2000): *Iron Oxides in the Laboratory.* Wiley-VCH. *(Standard reference on iron oxide minerals)*
- Delamare, F. \& Guineau, B. (2000): *Colour: Making and Using Dyes and Pigments.* Thames \& Hudson.
- Canti, M. (2003): Earthen pigments and their analysis. *English Heritage Research Transactions.*

### Online Resources

- **Public Lab** ([publiclab.org](https://publiclab.org)): DIY spectrometer instructions
- **Earth Pigments** ([earthpigments.com](https://earthpigments.com)): Reference colours and mineralogical background
- **ZALF Müncheberg** ([zalf.de](https://www.zalf.de)): Possible collaboration for soil analysis (project partner)

* * *

## License and Attribution

© 2025–2026 Michel Garand | Erdpuls — Center for Sustainability Literacy, Citizen Science & Reciprocal Economics

Licensed under [Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)](https://creativecommons.org/licenses/by-nc-sa/4.0/)

You are free to share and adapt this material for non-commercial purposes, provided you give appropriate credit, provide a link to the license, indicate if changes were made, and distribute any adaptations under the same license.

All software components referenced in this document are licensed under the [GNU Affero General Public License v3.0 (AGPL-3.0)](https://www.gnu.org/licenses/agpl-3.0.html)

*This document and its translations were developed with assistance from Claude (Anthropic PBC). All strategic decisions, philosophical positions, and project commitments are those of the author.*

**Contact:** erdpuls@ubec.network · [https://erdpuls.ubec.network](https://erdpuls.ubec.network)

*Alle Dokumente und ihre Übersetzungen / All documents and their translations.*
*February 2026*