The brief Read aloud by the marshal
Pat spends his days reading the dirt.
You’ve got acidic soil, basic soil, and four colours to hit.
Mix by ratio. Test. Match the colour. Each experiment has a grid — acid across, base down. Land on the right cell and you’ll find a letter.
Four colours. Four letters. One lock. Crack the code. Open the box. That’s the job.
How it cracks Four experiments · one code
Mix acid + base scoops until your test hits the target swatch.
Find your acid:base ratio cell. The letter inside is yours.
Four colours → four letters. Record in experiment order.
Enter the four letters. Lock opens or it doesn’t.
The grid & the lock One grid per colour · four-letter code
Ratio grid · sample
The 4-code lock
Enter in experiment order — Colour 1 → 2 → 3 → 4.
Marshal holds the true code. Lock opens, you’re through.
Method Per colour · repeat four times
Materials & targets Four swatches · four grids · one lock
Sample A · Acidic
One end of the kit colour scale
Sample B · Basic
Other end of the scale
Four target swatches
- pH kit — liquid indicator or strips + chart
- 4 ratio grids — acid × base scoops, letters in cells
- 4-code lock — letters in experiment order
- Locked box — holds next QR / stamp
- Scoops — same size · 1 scoop = 1 grid step
- Cups · water · gloves · wipes
Field rules Marshal has the key
Use only Sample A, Sample B, water, the kit, swatches, and grids.
Mix whole scoops that map to the grid axes. Don’t contaminate source pots.
Record the letter from the cell that matches your ratio — not the closest-looking one.
No phones for pH charts, colour pickers, or reverse-looking up the code.
Enter the four letters on the lock in experiment order (1 → 2 → 3 → 4).
Wrong code: lock stays shut. Keep mixing. Don’t force it or swap grids.
Bag waste soil. Leave the park cleaner than you found it.
Marshal may say “close enough” on colour — but the letter is still the one in your claimed cell.