Combining Milton tablets, a hydrogen-water generator, a water distiller and MEL Science kits — safe experiments for a 13-year-old (rust, batteries, galvanic cells, conductivity)

Overview — what you will learn

These experiments let you explore: why distilled water behaves differently from tap water; how ions (salt, disinfectant) affect electrical conductivity; how galvanic cells (lemon battery, Daniel cell) make voltage; how rust forms and how sacrificial protection works; and what an electrolysis (hydrogen-water) device actually does. Adult supervision and safety rules are required.

Important safety rules (read this first)

• Always wear safety goggles and chemical-resistant gloves. Work with an adult present.
• Do not mix Milton tablets (chlorine disinfectant) with acids, ammonia, hydrogen peroxide or other cleaners — that can make toxic gases (chlorine, chloramines).
• Do not try to collect or ignite hydrogen gas from any electrolysis device — hydrogen is flammable. Use the hydrogen-water generator only as intended and do not modify it.
• Follow the MEL Science kit instructions and safety advice for any chemicals they supply.
• Do experiments in a well-ventilated area, on a tray or bench you can easily clean. Label all containers. Dispose of solutions as instructed by adults and local rules.

1) Make distilled water (useful for many comparisons)

Why: Distilled water has most dissolved ions removed. That makes it a poor conductor compared with tap water. Use your water distiller to make distilled water and store it in a clean bottle.

2) Compare conductivity: distilled water vs tap vs salt vs Milton solution

Materials

• Multimeter (set to measure resistance or conductivity) or a very small LED + resistor + 9 V battery and test leads
• Four small clear cups labeled: distilled, tap, salt, Milton
• Table salt (NaCl)
• Milton tablet (dissolved at the manufacturer’s household dilution — read the packaging and have an adult prepare it)

Procedure

1. Fill the cups: distilled water; tap water; salt water (~1 teaspoon salt in 100 mL); Milton solution at the recommended dilution (an adult prepares this).
2. Measure resistance or try to light the LED briefly by placing the test leads into the liquid (the LED will only light if there is enough conductivity). Record which liquids conduct best.

What to expect and why

Distilled water shows very little conductivity. Tap water and salt water conduct well because they have dissolved ions. Milton solution contains chlorine-releasing ions and will conduct — note that disinfectants that add chloride or other ions can increase conductivity. This explains why electrochemical cells or an electrolysis device behave differently with distilled vs tap water.

3) Rust experiment: which liquids speed up or slow down corrosion?

Materials

• Identical clean iron nails or steel screws (4), labeled A–D
• Four clear plastic cups
• Distilled water, tap water, salt water (1 tsp/100 mL), Milton solution (diluted per instructions)
• Permanent marker, tray, notebook for observations

Procedure

1. Place one nail in each cup and cover with the chosen liquid (A = distilled, B = tap, C = salt, D = Milton solution).
2. Leave them in a place where they won’t be disturbed. Observe and photograph daily for several days. Record color changes, pitting and how fast rust (iron oxide) appears.

Safety and disposal

Keep the Milton solution away from drains if local rules forbid pouring disinfectant down the sink — follow the product advice. Wear gloves to handle rusty nails.

What you will learn

Salt (chloride) and chlorine-containing solutions can accelerate corrosion. Distilled water often causes less rapid corrosion because it lacks ions that carry current and support the electrochemical reactions needed for rusting.

4) Sacrificial anode (zinc protects iron)

Materials

• Two identical iron nails, one small zinc-coated (galvanized) nail or a piece of zinc (if available)
• Two cups with the same solution (salt water recommended to speed action)

Procedure

1. Put one iron nail alone in cup 1 (salt water). In cup 2, tightly attach (wire, tape or zip tie) a zinc piece to the iron nail and place it in the same salt-water mix.
2. Observe over several days. The iron attached to zinc should show less rust while the zinc corrodes preferentially.

Why it works

Zinc is more easily oxidized (it has a more negative electrode potential) so it gives up electrons and corrodes instead of iron. This is the principle of sacrificial protection used on boat hulls and pipelines.

5) Lemon battery (simple galvanic cell)

Materials

• 1–2 lemons (or oranges), copper coin or copper strip, a galvanized nail (zinc-coated) or zinc strip, multimeter or small LED with resistor

Procedure

1. Roll a lemon to soften it. Insert the copper electrode and the zinc electrode about 2–3 cm apart (don’t let them touch).
2. Measure the voltage with the multimeter (expect around 0.6–1.0 V for one lemon). To light a small LED you might need several lemons in series.

Why it works

The acid (citric acid) in the lemon helps create a pathway for ions. Zinc oxidizes (Zn → Zn2+ + 2e−) and copper is the reduction electrode; electrons flow through the wire from zinc to copper, producing a small voltage.

6) Daniel (Daniell) cell — safer approach using MEL Science kit instructions

The classic Daniel cell uses a zinc electrode in a zinc sulfate solution and a copper electrode in copper sulfate solution, connected by a salt bridge. Because copper sulfate is a chemical with toxicity to aquatic life, follow the MEL Science kit steps and safety guidance supplied with the kit.

General principles (if using the kit)

• Use distilled water for preparing solutions when the kit instructs — that gives clearer, more reproducible results.
• The expected voltage is around 1.0–1.1 V for a Zn|Zn2+//Cu2+|Cu cell.
• Observe copper plating on the copper electrode and zinc dissolving at the other electrode.

Do not:

• Increase reagent concentrations or mix chemicals beyond the kit instructions.
• Dispose of heavy-metal solutions down the drain — follow the kit disposal instructions and local rules.

7) Using the hydrogen-water generator safely to demonstrate electrolysis

Do not try to collect or ignite gases. Instead, use the generator to show how electrolysis depends on conductivity: run it with distilled water and then with tap water (or a very mild salt solution) and observe bubble production and appearance. You should see much less bubbling in distilled water because it has fewer ions to carry current. This is a useful demonstration of why distilled water is a poor conductor and why electrolysis devices often perform differently with different waters.

Safety reminder

Do not combine Milton tablets with the device or try to electrolyze a Milton/disinfectant solution. That could generate chlorine-containing gases — dangerous. Keep the hydrogen-water generator and Milton solutions separate.

Putting it all together — experiment plan sequence

1. Make distilled water in your distiller and label it.
2. Do the conductivity comparison (Section 2) to build intuition about ions and current.
3. Set up the rust experiment (Section 3) so it runs while you do other short experiments. Photograph every day.
4. Do the sacrificial-anode test (Section 4) to compare with the rust experiment.
5. Try the lemon battery (Section 5) and measure voltages; then assemble a small series string to try lighting an LED.
6. Follow your MEL Science kit to build the Daniel cell (Section 6) using distilled water when instructed — compare its voltage to the lemon battery and explain the differences using electrode potentials.
7. Use the hydrogen-water generator only to show bubble production differences in distilled vs tap water (Section 7). Do not collect gas or use it near flames.

Some key chemistry explanations (short)

• Rusting is an electrochemical oxidation of iron: Fe → Fe2+ + 2e−. The electrons reduce oxygen (usually) and water to make hydroxide and iron oxides.
• Electrolytes (ions) are needed for current in liquids. Distilled water has very few ions and so is a poor conductor.
• Chloride (from salt or some disinfectants) accelerates corrosion by breaking protective films and forming soluble iron-chloride species — that increases rust and pitting.
• In galvanic cells (lemon battery, Daniell cell) the cell voltage comes from the difference in reduction potentials of the two metals used (e.g., Zn vs Cu).

Troubleshooting and observations to look for

• If the LED won’t light from a lemon, try a multimeter first. You often need several cells in series to reach the LED forward voltage.
• If distilled water gives almost no bubble production in the hydrogen-water generator, that’s normal — adding very small amounts of ionic substance (not Milton) increases current but do not do this with disinfectant.
• Rust rate: tap and salt water usually show faster orange-brown rust; Milton solution may show pitting and other changes — document carefully with photos.

Final safety & responsible-use note

You can explore a lot of chemistry safely by following instructions, using diluted household forms of chemicals, and never mixing disinfectants with other cleaners or acids. Always follow the MEL Science kit safety sheet for any reagents it supplies. If you want to extend any experiment, ask an adult or teacher first and I can suggest safer next steps or more detailed chemical explanations.

If you'd like, I can: give a printable checklist of materials and safety equipment, write a day-by-day observation sheet for the rust test, or provide the exact expected voltages and reactions (with equations) for the lemon and Daniell cells. Which would you like next?