Teaching with the CoreBox

For teachers planning a unit. This page condenses the full German teaching concept ("Didaktikkonzept – CoreBox openUC2: Lichtwelten entdecken" available upon email request). Students don't need to read it.

At a glance

Target group	Sekundarstufe I (Kl. 5–10); extensions for Sek II
Scope	1–8 lessons, modular — single lessons, double lessons, project days, MINT clubs
Subjects	Physics; optional Biology (microscopy) and CS (digital imaging)
Group size	2–3 students per box
Room	normal classroom; dimmable helps for the projector lesson
Safety	no laser, no heat source in the box; only rule: never look at the sun through optics

The guiding idea: "Optik begreifen, indem man sie baut": students understand optics because they construct every instrument themselves, see every change of distance or lens produce a visible effect, and treat errors (blurry, upside-down, misaligned) as findable causes rather than failures.

Why build instead of using a finished microscope?

1. Construction creates understanding: ray paths aren't hidden in a housing.
2. Modularity invites experiments: every distance, lens and light can be varied.
3. Errors become teachable: a blurry or flipped image has a discoverable reason.
4. Digital integration: smartphone/tablet microscopy the way real labs do it.
5. Competency-oriented (KMK): supports Erkenntnisgewinnung, Fachwissen, Kommunikation and Bewertung in one material.

What the CoreBox is not: a precision optical bench. Compared to laboratory cage systems the builds are (deliberately) more playful and less rigid. The point is seeing the principles with modest means, not metrology. For university lab courses, treat it as an introductory / at-home / first-semester tool rather than a replacement for precision optics training.

Prerequisites

Required (usually covered in class 5–6): light travels in straight lines; shadow formation; describing observations; basic experimental habits. Helpful: first experience with magnifiers; terms like ray, object, image. Not needed: lens equation, any mathematics beyond mm-measurements.

The eight lessons

Each lesson pairs an experiment (tutorial/how-to page) with an explanation page. Order and selection are modular — the sequence below is the tested build-up.

#	Lesson	Build	Background page
1	Introduction: the magnifier	From lens to projector, steps 1–2	Light rays and lenses
2	Converging vs. diverging lenses	lens comparison + measure a focal length	Light rays and lenses
3	Image formation: the projector	From lens to projector, steps 3–4	How images form
4	Consolidation: image formation	projector variations, quantitative check of $1/f = 1/g + 1/b$	How images form
5	Telescopes: Galilei & Kepler	Build a telescope	How telescopes work
6	The classical (finite) microscope	Build the finite microscope	How a microscope works
7	The modern microscope: infinity optics	Build the infinity microscope	How a microscope works
8	Smartphone microscopy	Your first microscope + calibration	How a microscope works

Cube dismantling (Open and reconfigure a cube) slots naturally between lessons 5 and 6, when empty cubes are first needed.

Differentiated entry points

Depending on the group, you can also start with:

• the magnifier (low threshold, everyday reference),
• focal lengths (more theory-first),
• the telescope ("why is it upside-down?" as the driving question),
• tablet microscopy first (wow-factor entry, then work backwards).

A proven opener: pass around a smartphone, a rapid test, and a computer chip and ask what they have in common. None would exist without optics research.

KMK competency mapping (short form)

• Erkenntnisgewinnung: hypothesise => build => vary (distance, lens, light) => evaluate; the ray model as a worked example of modelling.
• Fachwissen: lens action, focal length, magnification (qualitative Sek I, quantitative Sek II), ray construction, instrument principles.
• Kommunikation: sketching setups and ray paths, correct use of terms (Brennweite, Zwischenbild, Vergrößerung — see glossary), documenting with photos, team roles.
• Bewertung: limits of instruments (field of view vs. magnification, empty magnification), error analysis, optics in everyday technology.

Classroom organisation

Roles that work (rotate them): one student directs the build from the instructions, one builds, one documents observations.

Methods mix: short demonstration impulses => group experiments => sketch/model phase => (digital) documentation => reflection. Compatible with 5E (Engage/Explore/Explain/Elaborate/Evaluate).

Preparation checklist (per box)

• Box complete? (check against Parts and parameters)
• Torch: batteries in and charged? Constant-light mode working?
• Samples: 2 prepared slides + blank slide present? Own samples prepared?
• Tablets/phones charged, cameras working?

After the unit

• Each box repacked completely
• Lenses clean (supplied cloth only), everything dry

Robustness, repairs, sustainability

The parts tolerate rough handling; if something does break, single modules can be re-bought or 3D-printed instead of replacing the box; repairing is part of the open-source concept. Risk of students "breaking something valuable" is low by design.

Extensions beyond this box

• Interferometry & holography: HoloBox (adds laser; separate safety briefing needed).
• Camera-based imaging, motorised stages: Electronics / Infinity add-ons.
• Programming: smartphone image analysis (pixel measurements from the calibration guide) bridges into CS lessons.