Overview — What you will learn

This guide connects three things: (1) the medieval / Middle Ages' practical observations (blacksmithing, rusting, alchemy), (2) the playful idea in The Science of Discworld that storytelling and clear models help us imagine science, and (3) safe, hands-on experiments you can do with a Mel Science "Chemistry: Corrosion" kit and a Mel Science "Chemistry & Electricity" kit. You will learn what corrosion is (chemically), basic electricity (voltage, current, circuits), how electrochemistry links the two, and how people in the Middle Ages observed these effects without knowing the microscopic causes.

Safety first

• Always wear safety goggles and gloves provided with the kits.
• Work in a well-ventilated area. Keep long hair tied back and avoid loose clothing near setups.
• Use only the reagents and components in the Mel Science kits and follow kit chemical disposal instructions. If you’re unsure, ask a teacher or adult to help.
• Keep liquids away from electronics and never use household mains power in experiments — the kits use low-voltage batteries which are safe when used correctly.

Context: Middle Ages vs modern science

In the Middle Ages, blacksmiths and shipbuilders saw metal corrode (rust) and developed practical protections (oil, paint, alloys) but didn’t have atomic theory or electrochemistry. Alchemists searched for transformations and substances but lacked reproducible scientific methods. The Science of Discworld pairs imaginative stories with real science; similarly, we’ll use simple models and experiments to turn observations (what you see) into explanations (why it happens).

Experiment 1 — Compare rusting: saltwater vs distilled water

What you’ll learn: How electrolyte presence (salt) speeds up iron corrosion (rust).

Materials (from the kit)

• Two clean iron nails (or steel screws)
• Two clear cups or beakers
• Salt (sodium chloride)
• Distilled water
• Permanent marker to label cups

Steps

1. Label the cups: "Saltwater" and "Distilled".
2. Fill both cups with distilled water to the same level.
3. Add about 1–2 teaspoons of salt to the "Saltwater" cup and stir until dissolved.
4. Place an iron nail in each cup so the metal is submerged. Leave them undisturbed for several days (check daily and record observations).

What to observe and record

• When does rust first appear in each cup?
• Which nail gets more orange/brown scale? Note texture and amount.

Why it happens (brief chemistry)

Rust is an oxidation reaction: iron atoms lose electrons and react with oxygen and water to form hydrated iron oxides (commonly written approximately as Fe2O3·xH2O). Saltwater is a better electrical conductor (it contains ions), so it helps the electrochemical reactions that produce rust proceed faster. In simple terms: salt speeds up the flow of ions needed for the redox reactions, so corrosion is faster.

Experiment 2 — Galvanic (bimetal) corrosion: iron and copper together

What you’ll learn: When two different metals touch in an electrolyte, one corrodes faster due to galvanic coupling.

Materials

• Iron nail (or steel)
• Small copper strip or wire
• Saltwater (from Experiment 1)
• Small beaker or cup

Steps

1. Attach the copper piece to the iron nail so they touch (you can wrap copper wire around a nail).
2. Submerge the joined metals in saltwater, leaving part of them exposed so you can see which corrodes.
3. Leave for several days and observe changes to both metals.

Explanation

Different metals have different tendencies to lose electrons (different electrode potentials). When connected in an electrolyte, the metal that more readily loses electrons (the anodic metal, often iron) corrodes faster; the less-reactive metal (cathodic, usually copper) is protected. This is galvanic corrosion and explains why combining metals in wet environments can be risky unless managed.

Experiment 3 — Build a simple circuit and measure voltage/current

What you’ll learn: Basic circuit concepts — voltage (V), current (I), resistance (R) and Ohm’s law. This helps you understand electric causes of some corrosion processes.

Materials

• From Mel Science electronics module: battery pack (or low-voltage power source), wires, resistor, LED or small bulb, multimeter (if included)

Steps

1. Connect a battery to a resistor and then to an LED in series to make a simple circuit. Use the diagram in your kit manual.
2. Use the multimeter to measure the voltage across the battery and the current through the circuit (follow multimeter instructions carefully).
3. Change the resistor value and observe how current and brightness change. Record V and I and verify Ohm's law: V = I * R.

Why it matters for corrosion

Current flow and external voltages can accelerate or direct corrosion. For example, stray currents in pipelines can cause severe corrosion where electricity flows through metal structures in electrolytes.

Experiment 4 — Electroplating or electrolytic deposition (simple and safe)

What you’ll learn: How passing current through a solution causes metal ions to deposit on a conductive surface (reduction at the cathode).

Materials (check kit contents and instructions)

• Small copper electrode or copper wire
• A part to plate (e.g., a small steel washer) cleaned and mechanically polished
• Copper sulfate solution (only if included in your kit) or a recommended substitute as per kit manual
• Low-voltage DC source (provided by kit)

Steps (follow the kit manual; below is a conceptual outline)

1. Prepare the electrolyte (copper sulfate solution) exactly as the kit instructs.
2. Connect the copper electrode to the positive terminal (anode) and the part to plate to the negative terminal (cathode).
3. Immerse both electrodes in the solution without them touching. Turn on the power at the low voltage recommended by the kit.
4. Watch copper slowly deposit onto the cathode surface. Turn off the power after the recommended time and rinse the plated part carefully.

Chemistry of plating

At the cathode: Cu2+ + 2 e- → Cu (metallic copper deposits). At the anode (if it’s copper): Cu → Cu2+ + 2 e- (which replenishes copper ions in solution). This is electrochemistry in action and is related to the same redox ideas behind corrosion.

Experiment 5 — Sacrificial anode demonstration

What you’ll learn: How a more reactive metal protects a less reactive one (used on ship hulls and pipelines).

Materials

• Iron nail
• Small strip of zinc (or magnesium if provided in kit)
• Saltwater cup

Steps

1. Attach the zinc strip to the iron nail so they touch electrically and place in saltwater.
2. Compare this setup to an iron nail alone in saltwater (from Experiment 1).
3. Observe which piece corrodes (zinc corrodes preferentially), protecting the iron.

Reaction (concept)

Zinc has a higher tendency to oxidize: Zn → Zn2+ + 2 e-. Those electrons prevent iron from oxidizing, so iron remains intact longer. This is how sacrificial anodes protect structures in real-world engineering.

Questions to think about (scientific method and The Science of Discworld angle)

• How would you design a controlled experiment to test paint vs oil vs galvanization as corrosion protection?
• What assumptions or models did people in the Middle Ages make about metal changes? How do modern models (atoms, electrons, redox potentials) give better predictions?
• Using Discworld-style imagination: if you invent a story-based model for rust, what would it predict, and how would you test it experimentally?

Troubleshooting and notes

• If a nail doesn’t show visible rust quickly, ensure it’s iron/steel (some nails are stainless). Rough the surface lightly to expose fresh metal.
• If electroplating looks patchy, clean the cathode surface properly — oil or oxide layers prevent even deposition.
• When measuring small currents, ensure multimeter settings and leads are correct; otherwise you might get no reading or blow a fuse in the meter.

Wrap-up and further exploration

These experiments link practical medieval observations (what people saw and how they reacted) with modern chemical explanations (atomic and electronic models). The Science of Discworld encourages using stories and thought experiments to make science accessible — use that creativity to design new tests: try different electrolytes, temperature effects on corrosion rate, or measure potentials between various metal pairs. Always follow kit instructions and safety guidance when you extend experiments.

If you want, tell me which Mel Science kit components you have available (exact reagents or parts) and I can give a tailored step-by-step protocol that matches them precisely.